Search This Blog

Wednesday, August 10, 2022

Traditional ecological knowledge

From Wikipedia, the free encyclopedia

Traditional ecological knowledge (TEK) describes indigenous and other traditional knowledge of local resources. As a field of study in Northern American anthropology, TEK refers to "a cumulative body of knowledge, belief, and practice, evolving by accumulation of TEK and handed down through generations through traditional songs, stories and beliefs. It is concerned with the relationship of living beings (including human) with their traditional groups and with their environment." It is important to note that indigenous knowledge is not a universal concept among various societies, but is referred to a system of knowledge traditions or practices that are heavily dependent on "place". Such knowledge is used in natural resource management as a substitute for baseline environmental data in cases where there is little recorded scientific data, or may complement Western scientific methods of ecological management.

The application of TEK in the field of ecological management and science is still controversial, as methods of acquiring and collecting knowledge—although often including forms of empirical research and experimentation—differ from those used to create and validate scientific ecological knowledge from a Western perspective. Non-tribal government agencies, such as the U.S. EPA, have established integration programs with some tribal governments in order to incorporate TEK in environmental plans and climate change tracking.

There is a debate whether Indigenous populations retain an intellectual property right over traditional knowledge and whether use of this knowledge requires prior permission and license. This is especially complicated because TEK is most frequently preserved as oral tradition and as such may lack objectively confirmed documentation. As such, the same methods that could resolve the issue of documentation to meet Western requirements may compromise the very nature of traditional knowledge.

Traditional knowledge is used to maintain resources necessary for survival. While TEK itself, and the communities tied to the oral tradition, may become threatened in the context of rapid climate change or environmental degradation, TEK is proving critical for understanding the impacts of those changes within the ecosystem.

TEK can also refer to traditional environmental knowledge which emphasizes the different components and interactions of the environment.

Development of the field

The earliest systematic studies of TEK were conducted in anthropology. Ecological knowledge was studied through the lens of ethnoecology, "an approach that focuses on the conceptions of ecological relationships held by a people or a culture," in understanding how systems of knowledge were developed by a given culture. Harold Colyer Conklin, an American anthropologist who pioneered the study of ethnoscience, took the lead in documenting indigenous ways of understanding the natural world. Conklin and others documented how traditional peoples, such as Philippine horticulturists, displayed remarkable and exceptionally detailed knowledge about the natural history of places where they resided. Direct involvement in gathering, fashioning products from, and using local plants and animals created a scheme in which the biological world and the cultural world were tightly intertwined. Although the field of TEK began with documentation of lists of species used by different indigenous groups and their "taxonomies of plants, animals, and later, of other environmental features such as soils," the shift from documentation to consideration of functional relationships and mechanisms gave rise to the field as it is recognized today. In emphasizing the study of adaptive processes, which argues that social organization itself is an ecological adaptational response by a group to its local environment, human-nature relations and the practical techniques on which these relationships and culture depended, the field of TEK could analyze a broad range of questions related to cultural ecology and ecological anthropology.

By the mid-1980s a growing body of literature on traditional ecological knowledge documented both the environmental knowledge held by diverse indigenous peoples and their ecological relations. The studies included examining "cultivation and biodiversity conservation in tropical ecosystems, and traditional knowledge and management systems in coastal fisheries and lagoons, semi-arid areas, and the Arctic." What these studies illustrated was that a variety of "traditional peoples had their own understandings of ecological relationships and distinct traditions of resource management." The rise of traditional ecological knowledge at this time led to international recognition of its potential applications in resource management practices and sustainable development. The 1987 report by the World Commission on Environment and Development reflects the consensus at the time. The report points out that the successes of the 20th century (decreases in infant mortality, increases in life expectancy, increases in literacy, and global food production) have given rise to trends that have caused environmental decay "in an ever more polluted world among ever decreasing resources." Hope, however, existed for traditional lifestyles. The report declared that tribal and indigenous peoples had lifestyles that could provide modern societies with lessons in the management of resources in complex forest, mountain, and dryland ecosystems.

Differences from science

Comparing TEK and Western Science

Fulvio Mazzocchi of the Italian National Research Council's Institute of Atmospheric Pollution contrasts traditional knowledge from scientific knowledge as follows:

Traditional knowledge has developed a concept of the environment that emphasizes the symbiotic character of humans and nature. It offers an approach to local development that is based on co‐evolution with the environment, and on respecting the carrying capacity of ecosystems. This knowledge--based on long‐term empirical observations adapted to local conditions--ensures a sound use and control of the environment, and enables indigenous people to adapt to environmental changes. Moreover, it supplies much of the world's population with the principal means to fulfil their basic needs, and forms the basis for decisions and strategies in many practical aspects, including interpretation of meteorological phenomena, medical treatment, water management, production of clothing, navigation, agriculture and husbandry, hunting and fishing, and biological classification systems.... Beyond its obvious benefit for the people who rely on this knowledge, it might provide humanity as a whole with new biological and ecological insights; it has potential value for the management of natural resources and might be useful in conservation education as well as in development planning and environmental assessment...Western science is positivist and materialist in contrast to traditional knowledge, which is spiritual and does not make distinctions between empirical and sacred. Western science is objective and quantitative as opposed to traditional knowledge, which is mainly subjective and qualitative. Western science is based on an academic and literate transmission, while traditional knowledge is often passed on orally from one generation to the next by the elders.

Aspects of traditional ecological knowledge

The aspects of traditional ecological knowledge provide different typologies in how it is utilized and understood. These are good indicators in how it is used from different perspectives and how they are interconnected, providing more emphasis on "cooperative management to better identify areas of difference and convergence when attempting to bring two ways of thinking and knowing together."

Factual observations

Houde identifies six faces of traditional ecological knowledge. The first aspect of traditional ecological knowledge incorporates the factual, specific observations generated by recognition, naming, and classification of discrete components of the environment. This aspect is about understanding the interrelationship with species and their surrounding environment. It is also a set of both empirical observations and information emphasizing the aspects of animals and their behavior, and habitat, and the physical characteristics of species, and animal abundance. This is most useful for risk assessment and management which provides nations with opportunity to influence resource management. However, if a nation does not act, then the state may act on its own interests. This type of "empirical knowledge consists of a set of generalized observations conducted over a long period of time and reinforced by accounts of other TEK holders."

Management systems

The second face refers to the ethical and sustainable use of resources in regards to management systems. This is achieved through strategic planning to ensure resource conservation. More specifically this face involves dealing with pest management, resource conversion, multiple cropping patterns, and methods for estimating the state of resources. It also focuses on resource management and how it adapts to local environments.

Past and current uses

The third face refers to the time dimension of TEK, focusing on past and current uses of the environment transmitted through oral history, such as land use, settlement, occupancy, and harvest levels. Specifically medicinal plants and historical sites are great concerns. Oral history is used to transmit cultural heritage generation to generation, and contributes to a sense of family and community.

Ethics and values

The fourth face refers to value statements and connections between the belief system and the organization of facts. In regards to TEK it refers to environmental ethics that keeps exploitative abilities in check. This face also refers to the expression of values concerning the relationship with the habitats of species and their surrounding environment - the human-relationship environment.

Culture and identity

Traditional Ecological Knowledge frequently relates to knowledge surrounding plants and foliage.

The fifth face refers to the role of language and images of the past giving life to culture. The relationship between Aboriginals (original inhabitants) and their environment is vital to sustaining the cultural components that define them. This face reflects the stories, values, and social relations that reside in places as contributing to the survival, reproduction, and evolution of aboriginal cultures, and identities. It also stresses "the restorative benefits of cultural landscapes as places for renewal"

Cosmology

The sixth face is a culturally based cosmology that is the foundation of the other aspects. Cosmology is the notion of how the world works for many cultures. This can vary greatly from one culture to the next. In the U.S for example, there are over 577 federally recognized tribes with their own culture, languages and belief system. Many of these tribes understand themselves as interconnected with the land. The term 'cosmology' relates to the assumptions and beliefs about how things work, and explains the way in which things are connected, and gives principles that regulate human-animal relations and the role of humans in the world. From an anthropological perspective, cosmology attempts to understand the human-animal relationship and how these directly influence social relationships, obligations toward community members, and management practices.

In A Yupiaq Worldview: A Pathway to Ecology and Spirit by Angayuqaq Oscar Kawagley, an Indigenous anthropologist, says "The balance of nature, or ecological perspective, was of utmost importance to the Yupiaq. History and archeological findings of different race in the world seem to indicate a common philosophical or ecological thread among all people, and this apparent linking leads to the concept of interconnectedness of all things of the universe. The Yupiaq people were, and still are, proponents of this worldview, in spite of the weakening of the ecological perspective by modern intrusions." Kawagley elaborates more on TEK in the Yupiaq worldview by saying that, "The Yupiaq person's methodologies include observation, experience, social interaction, and listening to the conversations and interrogations of the natural and spiritual worlds with the mind. The person is always a participant-observer."

Ecosystem management

An example of this is the Australian government giving back land to the Aboriginal people to practice their tradition of controlled fires. This made the areas more biologically diverse and decreased the threat of wildfires and their severity.

Ecosystem management is a multifaceted and holistic approach to natural resource management. It incorporates both science and traditional ecological knowledge to collect data from long term measures that science cannot. This is achieved by scientists and researchers collaborating with Indigenous peoples through a consensus decision-making process while meeting the socioeconomic, political and cultural needs of current and future generations. Indigenous knowledge has developed a way to deal with the complexity while western science has the techniques and tools. This is a good relationship to have which creates a better outcome for both sides and the environment. The dangers of working together is that nations do not benefit fairly or at all. Many times Indigenous knowledge has been used outside of the nation without consent (cultural appropriation), acknowledgment, or compensation. Indigenous knowledge can sustain the environment, yet it can be sacred knowledge.

Ecological restoration

Ecological restoration is the practice of restoring a degraded ecosystem through human intervention. There are many links between ecological restoration and ecosystem management practices involving TEK, however TEK ecosystem management is much more in-depth through the historical relationship with the place. Due to the aforementioned unequal power between indigenous and non-indigenous peoples, it is vital that partnerships are equitable to restore social injustices and this has proven to be successful when Indigenous Peoples lead ecological restoration projects.

Traditional knowledge and the U.S. Environmental Protection Agency

The U.S. Environmental Protection Agency was one of the first federal agencies to develop formal policies detailing how it would collaborate with tribal governments and acknowledge tribal interests in enacting its programs "to protect human health and the environment." In recognizing tribal peoples connection to the environment the EPA has sought to develop environmental programs that integrate traditional ecological knowledge into the "agency's environmental science, policy, and decision-making processes."

Although TEK is not currently recognized as an important component of mainstream environmental decision making, scientists are working on developing core science competency programs that align with TEK and promote self-sufficiency and determination. The lack of recognition for traditional ecological knowledge in determining solutions to environmental issues is representational of the ethnocentric tendency to value science over traditional models. Therefore, agencies integrating science and TEK must acknowledge the values of unique pedagogical methods in order to fully utilize the benefits of both science and TEK. For example, US agencies must learn about TEK through the lens of indigenous groups by working side by side with Indigenous Elders, gather hands-on data from the specific place in question, and incorporating indigenous values into their scientific evaluation.

In November 2000, U.S. President Bill Clinton issued Executive Order 13175, which required federal departments and agencies to consult with Indian Tribal governments in the development of policies that would have Tribal implications. Tribal Implications are defined by the EPA as having "substantial direct effects on one or more Indian tribes, on the relationship between the federal government and Indian tribes, or on the distribution of power and responsibilities between the federal government and Indian tribes." As a Federal agency of the U.S. government, the EPA was required to establish a set of standards for the consultation process. As its initial response, the agency developed a set of standards that would allow for meaningful communication and coordination between the agency and tribal officials prior to the agency taking actions or implementing decisions that may affect tribes. The standards also designated EPA consultation contacts to promote consistency and coordination of the consultation process, and established management oversight and reporting to ensure accountability and transparency.

One form of consultation has been EPA Tribal Councils. In 2000, the EPA's Office of Research and Development formed the EPA Tribal Science Council. The council, made up of representatives from tribes across the nation, is meant to provide a structure for tribal involvement in EPA's science efforts, and serve as a vehicle through which EPA may gain an understanding of the scientific issues that are of highest priority to tribes at a national level. The council also offers tribes an opportunity to influence EPA's scientific agenda by raising these priority issues to an EPA-wide group.

Of importance for tribal members at the initial gathering of the EPA Tribal Science Council was the inherent differences in tribal traditional lifeways and western science. These lifeways include "spiritual, emotional, physical, and mental connections to the environment; connections which are based on intrinsic, immeasurable values"; and an understanding that the earth's resources will provide everything necessary for human survival.

The EPA's Tribal Science Council, however, was meant to act as a meeting place where both groups could "share information that may contribute to environmental protection for all peoples with neither culture relinquishing its identity." In an effort to protect TTL the Council identified subsitence as a critical area for investigation. The EPA-Tribal Science Council defined subsistence as: the "relationships between people and their surrounding environment, a way of living. Subsistence involves an intrinsic spiritual connection to the earth, and includes an understanding that the earth's resources will provide everything necessary for human survival. People who subsist from the earth's basic resources remain connected to those resources, living within the circle of life. Subsistence is about living in a way that will ensure the integrity of the earth's resources for the beneficial use of generations to come." Because TTL or TEK is specific to a location and includes the relationships between plants and animals, and the relationship of living beings to the environment, acknowledgment of subsitence as a priority allows for the knowledge and practices of TTL to be protected. For example, as part of their deliberation regarding subsistence, the Council agreed to identify resource contamination as "the most critical tribal science issue at this time." Because tribal people with subsistence lifestyles rely the environment for traditional techniques of farming, hunting. fishing, forestry, and medicines, and ceremonies, contaminants disproportionately impact tribal peoples and jeopardizes their TTL. As the EPA Council stated, "Tribal subsistence consumption rates are typically many times higher than those of the general population, making the direct impact of resource contamination a much more immediate concern." As native peoples struggle with tainted resources, the council has made progress in investigating its impacts.

Despite such efforts, there are still barriers to progress within the EPA-Tribal Science Council. For example, one obstacle has been the nature of TTL. Tribal Traditional Lifeways are passed down orally, from person to person, generation to generation, whereas western science relies on the written word, communicated through academic and literate transmission. Endeavors to bring together western scientists and tribal people have also been hindered by Native American's perceptions that scientific analysis are put in a metaphorical "black box" that shuts out tribal input. Regardless, the EPA has recognized the ability of indigenous knowledge to advance scientific understanding and provide new information and perspectives that may benefit the environment and human health.

The integration of TTL into the EPA's risk assessment paradigm is one example of how the EPA-Tribal Science Council has been able to enact change in EPA culture. The risk assessment paradigm is an "organizing framework for the scientific analysis of the potential for harmful impacts to human health and the environment as a result of exposure to contaminants or other environmental stressors." Risk assessment has been used by the EPA to establish "clean-up levels at hazardous waste sites, water quality and air quality criteria, fish advisories, and bans or restricted uses for pesticides and other toxic chemicals." Tribal people are concerned, however, that current risk assessment methodologies do not afford complete value to tribal culture, values, and/or life ways. The Tribal Science Council seeks to incorporate TTL into exposure assumptions existent in the EPA risk assessment model. A long-term goal for the EPA's Tribal Science Council, however, is a complete shift in decision-making assessments from risk to preserving a healthy people and environment. As stated above, tribal people do not accept a separation of the human and ecological condition when they characterize risk. Through EPA initiated seminar, workshops, and projects, tribes have been able to engage in dialogue about the integration of Tribal Traditional Lifeways into EPA risk assessment and decision-making. This has occurred in a number of ways: inclusion of unique tribal cultural activities such as native basketry, the importance of salmon and other fishes, native plant medicine, consumption of large amounts of fish and game, and sweat lodges as exposures for estimating potential risk to people or to communities. Although these types of tribal specific activities may be included in EPA's risk assessment, there is no assurance that they will be included nor is there consistency in how they may be applied at different sites across the country.

In July 2014, the EPA announced its "Policy on Environmental Justice for Working with Federally Recognized Tribes and Indigenous Peoples," setting forth its principles for programs related to federally recognized tribes and indigenous peoples in order to "support the fair and effective implementation of federal environmental laws, and provide protection from disproportionate impacts and significant risks to human health and the environment." Among the 17 principles were #3 ("The EPA works to understand definitions of human health and the environment from the perspective of federally recognized tribes, indigenous peoples throughout the United States, and others living in Indian country"); #6 ("The EPA encourages, as appropriate and to the extent practicable and permitted by law, the integration of traditional ecological knowledge into the agency's environmental science, policy, and decision-making processes, to understand and address environmental justice concerns and facilitate program implementation"); and #7 ("The EPA considers confidentiality concerns regarding information on sacred sites, cultural resources, and other traditional knowledge, as permitted by law."). While this policy identifies guidelines and procedures for the EPA in regards to environmental justice principles as they relate to tribes and indigenous peoples, the agency noted that they are in no way applicable as rules or regulations. They cannot be applied to particular situations nor change or substitute any law, regulation, or any other legally-binding requirement and is not legally enforceable.

Effects of environmental degradation on traditional knowledge

In some areas, environmental degradation has led to a decline in traditional ecological knowledge. For example, at the Aamjiwnaang community of Anishnaabe First Nations people in Sarnia, Ontario, Canada, residents suffer from a "noticeable decrease in male birth ratio ..., which residents attribute to their proximity to petrochemical plants":

In addition to concerns about the physical reproduction of community members, indigenous people are concerned about how environmental contamination impacts the reproduction of cultural knowledge. In Aamjiwnaang, oral traditions once passed down from grandfathers during fishing or grandmothers during berry picking and medicine gathering are being lost as those activities are no longer practiced because of concerns about these foods being contaminated. Rocks once used for sweat lodges are no longer being collected from local streams because the streams have become contaminated. The cedar used for making tea, smudging, and washing babies contains vanadium at concentrations as high as 6 mg/kg..., reflecting local releases to air of > 611 tons of vanadium between 2001 and 2010.... At Akwesasne, community members report a loss of language and culture around subsistence activities like fishing, which have been largely abandoned because of fears of exposure to contaminants.

Climate change

Indigenous people and Climate Change: fact sheet about the health impacts of climate change on indigenous populations

Traditional ecological knowledge provides information about climate change across generations and geography of the actual residents in the area. Traditional ecological knowledge emphasizes and makes the information about the health and interactions of the environment the center of the information it carries. Climate change affects traditional ecological knowledge in the forms of the indigenous people's identity and the way they live their lives. Traditional knowledge is passed down from generation to generation and continues today. Indigenous people depend on these traditions for their livelihood. For many harvesting seasons, indigenous people have shifted their activity months earlier due to impacts from climate change.

The rising temperature poses as threats for ecosystems because it harms the livelihoods of certain tree and plant species. The combination of the rise in temperatures and change in precipitation levels affects plant growth locations.

The warming also affects insects and animals. The change in temperatures can affect many aspects from the times that insects emerge throughout the year to the changes in the habitats of animals throughout seasonal changes.

As the temperature gets hotter, wild fires become more likely. One Indigenous nation in Australia was recently given back land and are reinstating their traditional practice of controlled burning. This has resulted in increased biodiversity and decreased severity of wildfires.

Not only are different aspects of the environment affected, but together, the health of the ecosystem is affected by climate change and so the environmental resources available to the indigenous people can change in the amount available and the quality of the resources.

As sea ice levels decrease, Alaska Native peoples experience changes in their daily lives; fishing, transportation, social and economic aspects of their lives become more unsafe. The defrosting of soil has caused damages to buildings and roadways. Water contamination becomes exacerbated as clean water resources dwindle.

Climate changes undermine the daily lives of the Native peoples on many levels. Climate change and indigenous people have a varying relationship depending on the geographic region which require different adaption and mitigation actions. For example, to immediately deal with these conditions, the indigenous people adjust when they harvest and what they harvest and also adjust their resource use. Climate change can change the accuracy of the information of traditional ecological knowledge. The indigenous people have relied deeply on indicators in nature to plan activities and even for short- term weather predictions. As a result of even more increasing unfavorable conditions, the indigenous people relocate to find other ways to survive. As a result, there is a loss of cultural ties to the lands they once resided on and there is also a loss to the traditional ecological knowledge they had with the land there. Climate change adaptations not properly structured or implemented can harm the indigenous people's rights.

The EPA has mentioned that it would take traditional ecological knowledge into consideration in planning adaptations to climate change. The National Resource Conservation Service of the United States Department of Agriculture has used methods of the indigenous people to combat climate change conditions.

Case study: Savoonga and Shaktoolik, Alaska

In one study, villagers of Savoonga and Shaktoolik, Alaska reported that over the last twenty years of their lives, the weather has become more difficult to predict, the colder season has shortened, there is more difficulty in predicting the amount of plants available for harvests, there are differences in animal migrations, there are more sightings of new species than before, and the activities of hunting and gathering have become not as predictable nor occur as often due to more limited availability to do so. The residents saw a noticeable change in their climate which also affected their livelihoods. The plants and animals are not as consistent with their availability which affects the residents' hunting and gathering because there is not as much to hunt or gather. The appearance of new species of plants and animals is also a physical and nutritional safety concern because they are not traditionally part of the land.

Tribally Specific TEK

Karuk and Yurok Burning as TEK

According to environmental sociologist Kirsten Vinyeta and tribal climate change researcher Kathy Lynn, "the Karuk Tribe of California occupies aboriginal land along the middle course of the Klamath and Salmon Rivers in Northern California. The Tribe's aboriginal territory includes an estimated 1.38 million acres within the Klamath River Basin. Traditional burning practices have been critical to the Karuk since time immemorial. For the Tribe, fire serves as a critical land management tool as well as a spiritual practice." According to environmental studies professor Tony Marks-Block, ecological researcher Frank K. Lake and tropical forester Lisa M. Curran, "before widespread fire exclusion policies, American Indians used to broadcast understory fires or cultural burns to enhance resources integral for their livelihood and cultural practices. To restore ecocultural resources depleted from decades of fire exclusion and to reduce wildfire risks, the Karuk and the Yurok Tribes of Northwest California are leading regional collaborative efforts to expand broadcast fires and fuel reduction treatments on public, private, and Tribal lands in their ancestral territories."

Tony Marks-Block, Frank K. Lake and Lisa M. Curran also state that "in Karuk territory, the federal government did not establish a reservation, leaving merely 3.83 square kilometers of Karuk trust lands in their ancestral territory, with the remainder largely under the jurisdiction of the Klamath and Six Rivers National Forests and scattered private homesteads. As a result, Karuk Tribal members and management agencies must navigate the USDA Forest Service claims on their ancestral territory and have limited options to expand their land base through the acquisition of private land holdings. In Yurok territory, multiple overlapping jurisdictions occur including Redwood National Park and Six Rivers National Forest outside of the reservation established by the federal government. The reservation is under private timber company ownership. Consequently, the Yurok Tribe must either coordinate or interact with multiple actors within their ancestral territory, but they presently have greater options for acquiring private properties than the Karuk Tribe." According to professor of sociology Kari Norgaard and Karuk tribe member William Tripp, "this process can then be replicated and expanded to other communities throughout the western Klamath Mountains and beyond. Hoopa and Yurok tanoak stands that experienced repeated fire were more resilient to the disease over time. Some research indicates dramatic differences in disease incidence immediately following wildfire (72 times less likely to be found in burned versus unburned plots in the same area), although it has been shown to steadily recover in the absence of repeated fire, because the disease can survive in hosts not killed by the fire."

Anishinabe Ecological Conservation as TEK

According to authors Bobbie Kalman and Niki Walker, "indigenous, or Native, people have lived in the Great Lakes region for thousands of years. People of the Anishinabe (Anishinaabe) nation lived in territories in the western Great Lakes region. According to oral tradition, the Anishinabe people once lived by a huge body of salt water, which may have been the Atlantic Ocean or Hudson's Bay. The people received a prophecy, or prediction, that if they traveled inland, they would find a place where food grew on water. Some went west, following a vision of a megis, or cowrie shell, that guided them to the western Great Lakes. The people split into groups and settled in different spots that together made up the Anishinabe nation. The Anishinabe had an especially close relationship with two other nations in the western Great Lakes region being the Odawa (Ottawa) and Potawatomi. People of these three nations often married one another, traded goods, and worked together to settle disputes. They also gathered at councils, where they made decisions together."

According to indigenous philosopher and climate/environmental justice scholar Kyle Powys Whyte, "Anishinabe people throughout the Great Lakes region are at the forefront of native species conservation and ecological restoration. Nmé is the largest and oldest living fish in the Great Lakes basin, sometimes exceeding 100 years in age. Nmé served the Asnishinabe people as a substantial source of food, an indicator species for monitoring the environment, and a lachlan identity, playing a role in ceremonies and stories. Kenny Pheasant, an elder says, "Decline of the sturgeon has corresponded with decline in sturgeon clan families. Only a few sturgeon clan families are known around here" (Little River Band). The Natural Resources Department of the Ottawa Indians started a cultural context group, composed of a diverse range of tribal members and biologists, which developed goals and objectives for restoration. The goal was to "restore the harmony and connectivity between Nmé and the Anishinabe people and bring them both back to the river. Ultimately, the department created the first streamside rearing facility for protecting young sturgeon before they are released each fall in order to preserve their genetic parentage. Wild rice, or manoomin, grows in shallow, clear, and slow-moving waterways and can be harvested in early autumn. After harvesting, manoomin is processed through activities such as drying, parching, hulling, winnowing, and cleaning. After the Anishinabe migrated from the East and reached the Great Lakes region where they could grow crops on the water, neighboring groups of US and Canadian citizens and companies engaged in activities such as mining, damming, commercial farming and recreational boating. These activities directly affect manoomin and its habitat. Today the Anishinabe people are leaders in the conservation of wild rice. The Nibi (water) and Manoomin Symposium, which takes place every two years, brings tribal rice harvesters in the Great Lakes, indigenous scholars, paddy rice growers, representatives from mining companies and state agencies, and university researchers interested in the genetic modification of rice together. Elders share their stories about manoomin and youth share their perspective on how manoomin fits into their futures. Indigenous persons working as scientists in their tribes share the experiences working with elders to understand the deep historical implications of the work they do to study and conserve manoomin. Other indigenous people are often invited to share their experiences restoring and conserving other native species, such as taro and maize."

Lummi Nation of Washington State Conservation of Southern Resident Killer Whales as TEK

According to ecological scholars Paul Guernsey, Kyle Keeler and Lummi member Jeremiah Julius, "the Lummi Nation of Washington State is a native American tribe of the Salish Sea. In 2018, the Lummi Nation dedicated itself to a Totem Pole Journey across the United States calling for the return of their relative "Lolita" (a Southern Resident Killer Whale) to her home waters. In the Salish language, killer whales are referred to as qwe 'lhol mechen, meaning 'our relations under the waves', but the Lummi are not simply 'related to' the whales in a generic fashion, the whales are a relation in the sense that they are kin. When NOAA first designated the Southern Resident killer whale an endangered distinct population segment (DPS) in 2005, they juridically eliminated "Lolita" as a family member. The decision reads, "The Southern Resident killer whale DPS does not include killer whales from J, K or L pod placed in captivity prior to listing, nor does it include their captive born progeny" (NOAA, 2005). The Lummi are asking for NOAA to collaborate in feeding the whales until the chinook runs of the Puget Sound can sustain them. The Lummi have embarked on ceremonial feedings of their relatives, but they are told by NOAA that larger-scale efforts would require federal permission and partnership. Although one of the organization's conservation goals is to ensure 'sufficient quantity, quality and accessibility of prey species', NOAA understands this policy strictly as a habitat issue. They have been clear that now is not the time for complacency due to 'insufficient data' or uncertainty. The Lummi continue their annual Totem Pole Journey to protect their older siblings, the blackfish, and to keep coal, oil and other threats out of the Salish Sea. These healing practices are fashioned to address what Maria Yellow Horse Brave Heart and Lemyra M. DeBruyn have called "historical unresolved grief"."

Plant hormone

From Wikipedia, the free encyclopedia

Lack of the plant hormone auxin can cause abnormal growth (right)

Plant hormones (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pathogen defense, stress tolerance and through to reproductive development. Unlike in animals (in which hormone production is restricted to specialized glands) each plant cell is capable of producing hormones. Went and Thimann coined the term "phytohormone" and used it in the title of their 1937 book.

Phytohormones occur across the plant kingdom, and even in algae, where they have similar functions to those seen in higher plants. Some phytohormones also occur in microorganisms, such as unicellular fungi and bacteria, however in these cases they do not play a hormonal role and can better be regarded as secondary metabolites.

Characteristics

Phyllody on a purple coneflower (Echinacea purpurea), a plant development abnormality where leaf-like structures replace flower organs. It can be caused by hormonal imbalance, among other reasons.

The word hormone is derived from Greek, meaning set in motion. Plant hormones affect gene expression and transcription levels, cellular division, and growth. They are naturally produced within plants, though very similar chemicals are produced by fungi and bacteria that can also affect plant growth. A large number of related chemical compounds are synthesized by humans. They are used to regulate the growth of cultivated plants, weeds, and in vitro-grown plants and plant cells; these manmade compounds are called plant growth regulators (PGRs). Early in the study of plant hormones, "phytohormone" was the commonly used term, but its use is less widely applied now.

Plant hormones are not nutrients, but chemicals that in small amounts promote and influence the growth, development, and differentiation of cells and tissues. The biosynthesis of plant hormones within plant tissues is often diffuse and not always localized. Plants lack glands to produce and store hormones, because, unlike animals—which have two circulatory systems (lymphatic and cardiovascular) powered by a heart that moves fluids around the body—plants use more passive means to move chemicals around their bodies. Plants utilize simple chemicals as hormones, which move more easily through their tissues. They are often produced and used on a local basis within the plant body. Plant cells produce hormones that affect even different regions of the cell producing the hormone.

Hormones are transported within the plant by utilizing four types of movements. For localized movement, cytoplasmic streaming within cells and slow diffusion of ions and molecules between cells are utilized. Vascular tissues are used to move hormones from one part of the plant to another; these include sieve tubes or phloem that move sugars from the leaves to the roots and flowers, and xylem that moves water and mineral solutes from the roots to the foliage.

Not all plant cells respond to hormones, but those cells that do are programmed to respond at specific points in their growth cycle. The greatest effects occur at specific stages during the cell's life, with diminished effects occurring before or after this period. Plants need hormones at very specific times during plant growth and at specific locations. They also need to disengage the effects that hormones have when they are no longer needed. The production of hormones occurs very often at sites of active growth within the meristems, before cells have fully differentiated. After production, they are sometimes moved to other parts of the plant, where they cause an immediate effect; or they can be stored in cells to be released later. Plants use different pathways to regulate internal hormone quantities and moderate their effects; they can regulate the amount of chemicals used to biosynthesize hormones. They can store them in cells, inactivate them, or cannibalise already-formed hormones by conjugating them with carbohydrates, amino acids, or peptides. Plants can also break down hormones chemically, effectively destroying them. Plant hormones frequently regulate the concentrations of other plant hormones. Plants also move hormones around the plant diluting their concentrations.

The concentration of hormones required for plant responses are very low (10−6 to 10−5 mol/L). Because of these low concentrations, it has been very difficult to study plant hormones, and only since the late 1970s have scientists been able to start piecing together their effects and relationships to plant physiology. Much of the early work on plant hormones involved studying plants that were genetically deficient in one or involved the use of tissue-cultured plants grown in vitro that were subjected to differing ratios of hormones, and the resultant growth compared. The earliest scientific observation and study dates to the 1880s; the determination and observation of plant hormones and their identification was spread out over the next 70 years.

Classes

Different hormones can be sorted into different classes, depending on their chemical structures. Within each class of hormone, chemical structures can vary, but all members of the same class have similar physiological effects. Initial research into plant hormones identified five major classes: abscisic acid, auxins, brassinosteroids, cytokinins and ethylene. This list was later expanded, and brassinosteroids, jasmonates, salicylic acid, and strigolactones are now also considered major plant hormones. Additionally there are several other compounds that serve functions similar to the major hormones, but their status as bone fide hormones is still debated.

Abscisic acid

Abscisic acid

Abscisic acid (also called ABA) is one of the most important plant growth inhibitors. It was discovered and researched under two different names, dormin and abscicin II, before its chemical properties were fully known. Once it was determined that the two compounds are the same, it was named abscisic acid. The name refers to the fact that it is found in high concentrations in newly abscissed or freshly fallen leaves.

This class of PGR is composed of one chemical compound normally produced in the leaves of plants, originating from chloroplasts, especially when plants are under stress. In general, it acts as an inhibitory chemical compound that affects bud growth, and seed and bud dormancy. It mediates changes within the apical meristem, causing bud dormancy and the alteration of the last set of leaves into protective bud covers. Since it was found in freshly abscissed leaves, it was initially thought to play a role in the processes of natural leaf drop, but further research has disproven this. In plant species from temperate parts of the world, abscisic acid plays a role in leaf and seed dormancy by inhibiting growth, but, as it is dissipated from seeds or buds, growth begins. In other plants, as ABA levels decrease, growth then commences as gibberellin levels increase. Without ABA, buds and seeds would start to grow during warm periods in winter and would be killed when it froze again. Since ABA dissipates slowly from the tissues and its effects take time to be offset by other plant hormones, there is a delay in physiological pathways that provides some protection from premature growth. Abscisic acid accumulates within seeds during fruit maturation, preventing seed germination within the fruit or before winter. Abscisic acid's effects are degraded within plant tissues during cold temperatures or by its removal by water washing in and out of the tissues, releasing the seeds and buds from dormancy.

ABA exists in all parts of the plant, and its concentration within any tissue seems to mediate its effects and function as a hormone; its degradation, or more properly catabolism, within the plant affects metabolic reactions and cellular growth and production of other hormones. Plants start life as a seed with high ABA levels. Just before the seed germinates, ABA levels decrease; during germination and early growth of the seedling, ABA levels decrease even more. As plants begin to produce shoots with fully functional leaves, ABA levels begin to increase again, slowing down cellular growth in more "mature" areas of the plant. Stress from water or predation affects ABA production and catabolism rates, mediating another cascade of effects that trigger specific responses from targeted cells. Scientists are still piecing together the complex interactions and effects of this and other phytohormones.

In plants under water stress, ABA plays a role in closing the stomata. Soon after plants are water-stressed and the roots are deficient in water, a signal moves up to the leaves, causing the formation of ABA precursors there, which then move to the roots. The roots then release ABA, which is translocated to the foliage through the vascular system and modulates potassium and sodium uptake within the guard cells, which then lose turgidity, closing the stomata.

Auxins

The auxin, indole-3-acetic acid

Auxins are compounds that positively influence cell enlargement, bud formation, and root initiation. They also promote the production of other hormones and, in conjunction with cytokinins, control the growth of stems, roots, and fruits, and convert stems into flowers. Auxins were the first class of growth regulators discovered. A Dutch Biologist Frits Warmolt Went first described auxins. They affect cell elongation by altering cell wall plasticity. They stimulate cambium, a subtype of meristem cells, to divide, and in stems cause secondary xylem to differentiate.

Auxins act to inhibit the growth of buds lower down the stems in a phenomenon known as apical dominance, and also to promote lateral and adventitious root development and growth. Leaf abscission is initiated by the growing point of a plant ceasing to produce auxins. Auxins in seeds regulate specific protein synthesis, as they develop within the flower after pollination, causing the flower to develop a fruit to contain the developing seeds.

In large concentrations, auxins are often toxic to plants; they are most toxic to dicots and less so to monocots. Because of this property, synthetic auxin herbicides including 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) have been developed and used for weed control by defoliation. Auxins, especially 1-naphthaleneacetic acid (NAA) and indole-3-butyric acid (IBA), are also commonly applied to stimulate root growth when taking cuttings of plants. The most common auxin found in plants is indole-3-acetic acid (IAA).

Brassinosteroids

Brassinolide, a major brassinosteroid

Brassinosteroids are a class of polyhydroxysteroids, the only example of steroid-based hormones in plants. Brassinosteroids control cell elongation and division, gravitropism, resistance to stress, and xylem differentiation. They inhibit root growth and leaf abscission. Brassinolide was the first identified brassinosteroid and was isolated from extracts of rapeseed (Brassica napus) pollen in 1979. Brassinosteroids are a class of steroidal phytohormones in plants that regulate numerous physiological processes. This plant hormone was identified by Mitchell et al. who extracted ingredients from Brassica pollen only to find that the extracted ingredients’ main active component was Brassinolide. This finding meant the discovery of a new class of plant hormones called Brassinosteroids. These hormones act very similarly to animal steroidal hormones by promoting growth and development. In plants these steroidal hormones play an important role in cell elongation via BR signaling. Brassinosteroids receptor- brassinosteroid insensitive 1 (BRI1) is the main receptor for this signaling pathway. This BRI1 receptor was found by Clouse et al. who made the discovery by inhibiting BR and comparing it to the wildtype in Arabidopsis. The BRI1 mutant displayed several problems associated with growth and development such as dwarfism, reduced cell elongation and other physical alterations. These findings mean that plants properly expressing brassinosteroids grow more than their mutant counterparts. Brassinosteroids bind to BRI1 localized at the plasma membrane which leads to a signal cascade that further regulates cell elongation. This signal cascade however is not entirely understood at this time. What is believed to be happening is that BR binds to the BAK1 complex which leads to a phosphorylation cascade. This phosphorylation cascade then causes BIN2 to be deactivated which causes the release of transcription factors. These released transcription factors then bind to DNA that leads to growth and developmental processes  and allows plants to respond to abiotic stressors.

Cytokinins

Zeatin, a cytokinin

Cytokinins or CKs are a group of chemicals that influence cell division and shoot formation. They also help delay senescence of tissues, are responsible for mediating auxin transport throughout the plant, and affect internodal length and leaf growth. They were called kinins in the past when they were first isolated from yeast cells. Cytokinins and auxins often work together, and the ratios of these two groups of plant hormones affect most major growth periods during a plant's lifetime. Cytokinins counter the apical dominance induced by auxins; in conjunction with ethylene, they promote abscission of leaves, flower parts, and fruits.

Among the plant hormones, the 3 that are known to help with immunological interactions are ethylene (ET), salicylates (SA), and jasmonates (JA), however more research has gone into identifying the role that cytokinins (CK) play in this. Evidence suggests that cytokinins delay the interactions with pathogens, showing signs that they could induce resistance toward these pathogenic bacteria. Accordingly, there are higher CK levels in plants that have increased resistance to pathogens compared to those which are more susceptible. For example, pathogen resistance involving cytokinins was tested using the Arabidopsis species by treating them with naturally occurring CK (trans-zeatin) to see their response to the bacteria Pseudomonas syringa. Tobacco studies reveal that over expression of CK inducing IPT genes yields increased resistance whereas over expression of CK oxidase yields increased susceptibility to pathogen, namely P. syringae.

While there’s not much of a relationship between this hormone and physical plant behavior, there are behavioral changes that go on inside the plant in response to it.  Cytokinin defense effects can include the establishment and growth of microbes (delay leaf senescence), reconfiguration of secondary metabolism or even induce the production of new organs such as galls or nodules. These organs and their corresponding processes are all used to protect the plants against biotic/abiotic factors.

Ethylene

Ethylene

Unlike the other major plant hormones, ethylene is a gas and a very simple organic compound, consisting of just six atoms. It forms through the breakdown of methionine, an amino acid which is in all cells. Ethylene has very limited solubility in water and therefore does not accumulate within the cell, typically diffusing out of the cell and escaping the plant. Its effectiveness as a plant hormone is dependent on its rate of production versus its rate of escaping into the atmosphere. Ethylene is produced at a faster rate in rapidly growing and dividing cells, especially in darkness. New growth and newly germinated seedlings produce more ethylene than can escape the plant, which leads to elevated amounts of ethylene, inhibiting leaf expansion (see hyponastic response).

As the new shoot is exposed to light, reactions mediated by phytochrome in the plant's cells produce a signal for ethylene production to decrease, allowing leaf expansion. Ethylene affects cell growth and cell shape; when a growing shoot or root hits an obstacle while underground, ethylene production greatly increases, preventing cell elongation and causing the stem to swell. The resulting thicker stem is stronger and less likely to buckle under pressure as it presses against the object impeding its path to the surface. If the shoot does not reach the surface and the ethylene stimulus becomes prolonged, it affects the stem's natural geotropic response, which is to grow upright, allowing it to grow around an object. Studies seem to indicate that ethylene affects stem diameter and height: when stems of trees are subjected to wind, causing lateral stress, greater ethylene production occurs, resulting in thicker, sturdier tree trunks and branches.

Ethylene also affects fruit ripening. Normally, when the seeds are mature, ethylene production increases and builds up within the fruit, resulting in a climacteric event just before seed dispersal. The nuclear protein Ethylene Insensitive2 (EIN2) is regulated by ethylene production, and, in turn, regulates other hormones including ABA and stress hormones. Ethylene diffusion out of plants is strongly inhibited underwater. This increases internal concentrations of the gas. In numerous aquatic and semi-aquatic species (e.g. Callitriche platycarpus, rice, and Rumex palustris), the accumulated ethylene strongly stimulates upward elongation. This response is an important mechanism for the adaptive escape from submergence that avoids asphyxiation by returning the shoot and leaves to contact with the air whilst allowing the release of entrapped ethylene. At least one species (Potamogeton pectinatus) has been found to be incapable of making ethylene while retaining a conventional morphology. This suggests ethylene is a true regulator rather than being a requirement for building a plant's basic body plan.

Gibberellins

Gibberellin A1

Gibberellins (GAs) include a large range of chemicals that are produced naturally within plants and by fungi. They were first discovered when Japanese researchers, including Eiichi Kurosawa, noticed a chemical produced by a fungus called Gibberella fujikuroi that produced abnormal growth in rice plants. It was later discovered that GAs are also produced by the plants themselves and control multiple aspects of development across the life cycle. The synthesis of GA is strongly upregulated in seeds at germination and its presence is required for germination to occur. In seedlings and adults, GAs strongly promote cell elongation. GAs also promote the transition between vegetative and reproductive growth and are also required for pollen function during fertilization.

Gibberellins breaks the dormancy (in active stage) in seeds and buds and helps increasing the height of the plant. It helps in the growth of the stem.

Jasmonates

Jasmonic acid

Jasmonates (JAs) are lipid-based hormones that were originally isolated from jasmine oil. JAs are especially important in the plant response to attack from herbivores and necrotrophic pathogens. The most active JA in plants is jasmonic acid. Jasmonic acid can be further metabolized into methyl jasmonate (MeJA), which is a volatile organic compound. This unusual property means that MeJA can act as an airborne signal to communicate herbivore attack to other distant leaves within one plant and even as a signal to neighboring plants. In addition to their role in defense, JAs are also believed to play roles in seed germination, the storage of protein in seeds, and root growth.

JAs have been shown to interact in the signalling pathway of other hormones in a mechanism described as “crosstalk.” The hormone classes can have both negative and positive effects on each other's signal processes.

Jasmonic acid methyl ester (JAME) has been shown to regulate genetic expression in plants. They act in signalling pathways in response to herbivory, and upregulate expression of defense genes. Jasmonyl-isoleucine (JA-Ile) accumulates in response to herbivory, which causes an upregulation in defense gene expression by freeing up transcription factors.

Jasmonate mutants are more readily consumed by herbivores than wild type plants, indicating that JAs play an important role in the execution of plant defense. When herbivores are moved around leaves of wild type plants, they reach similar masses to herbivores that consume only mutant plants, implying the effects of JAs are localized to sites of herbivory. Studies have shown that there is significant crosstalk between defense pathways.

Salicylic acid

Salicylic acid

Salicylic acid (SA) is a hormone with a structure related to phenol. It was originally isolated from an extract of white willow bark (Salix alba) and is of great interest to human medicine, as it is the precursor of the painkiller aspirin. In plants, SA plays a critical role in the defense against biotrophic pathogens. In a similar manner to JA, SA can also become methylated. Like MeJA, methyl salicylate is volatile and can act as a long-distance signal to neighboring plants to warn of pathogen attack. In addition to its role in defense, SA is also involved in the response of plants to abiotic stress, particularly from drought, extreme temperatures, heavy metals, and osmotic stress.

Salicylic acid (SA) serves as a key hormone in plant innate immunity, including resistance in both local and systemic tissue upon biotic attacks, hypersensitive responses, and cell death. Some of the SA influences on plants include seed germination, cell growth, respiration, stomatal closure, senescence-associated gene expression, responses to abiotic and biotic stresses, basal thermo tolerance and fruit yield. A possible role of salicylic acid in signaling disease resistance was first demonstrated by injecting leaves of resistant tobacco with SA. The result was that injecting SA stimulated pathogenesis related (PR) protein accumulation and enhanced resistance to tobacco mosaic virus (TMV) infection. Exposure to pathogens causes a cascade of reactions in the plant cells. SA biosynthesis is increased via isochorismate synthase (ICS) and phenylalanine ammonia-lyase (PAL) pathway in plastids. It was observed that during plant-microbe interactions, as part of the defense mechanisms, SA is initially accumulated at the local infected tissue and then spread all over the plant to induce systemic acquired resistance at non-infected distal parts of the plant. Therefore with increased internal concentration of  SA, plants were able to build resistant barriers for pathogens and other adverse environmental conditions

Strigolactones

Strigolactones (SLs) were originally discovered through studies of the germination of the parasitic weed Striga lutea. It was found that the germination of Striga species was stimulated by the presence of a compound exuded by the roots of its host plant. It was later shown that SLs that are exuded into the soil also promote the growth of symbiotic arbuscular mycorrhizal (AM) fungi. More recently, another role of SLs was identified in the inhibition of shoot branching. This discovery of the role of SLs in shoot branching led to a dramatic increase in the interest in these hormones, and it has since been shown that SLs play important roles in leaf senescence, phosphate starvation response, salt tolerance, and light signalling.

Other known hormones

Other identified plant growth regulators include:

  • Plant peptide hormones – encompasses all small secreted peptides that are involved in cell-to-cell signaling. These small peptide hormones play crucial roles in plant growth and development, including defense mechanisms, the control of cell division and expansion, and pollen self-incompatibility. The small peptide CLE25 is known to act as a long-distance signal to communicate water stress sensed in the roots to the stomata in the leaves.
  • Polyamines – are strongly basic molecules with low molecular weight that have been found in all organisms studied thus far. They are essential for plant growth and development and affect the process of mitosis and meiosis. In plants, polyamines have been linked to the control of senescence and programmed cell death.
  • Nitric oxide (NO) – serves as signal in hormonal and defense responses (e.g. stomatal closure, root development, germination, nitrogen fixation, cell death, stress response). NO can be produced by a yet undefined NO synthase, a special type of nitrite reductase, nitrate reductase, mitochondrial cytochrome c oxidase or non enzymatic processes and regulate plant cell organelle functions (e.g. ATP synthesis in chloroplasts and mitochondria).
  • Karrikins – are not plant hormones as they are not produced by plants themselves but are rather found in the smoke of burning plant material. Karrikins can promote seed germination in many species. The finding that plants which lack the receptor of karrikin receptor show several developmental phenotypes (enhanced biomass accumulation and increased sensitivity to drought) have led some to speculate on the existence of an as yet unidentified karrikin-like endogenous hormone in plants. The cellular karrikin signalling pathway shares many components with the strigolactone signalling pathway.
  • Triacontanol – a fatty alcohol that acts as a growth stimulant, especially initiating new basal breaks in the rose family. It is found in alfalfa (lucerne), bee's wax, and some waxy leaf cuticles.

Use in horticulture

Synthetic plant hormones or PGRs are used in a number of different techniques involving plant propagation from cuttings, grafting, micropropagation and tissue culture. Most commonly they are commercially available as "rooting hormone powder".

The propagation of plants by cuttings of fully developed leaves, stems, or roots is performed by gardeners utilizing auxin as a rooting compound applied to the cut surface; the auxins are taken into the plant and promote root initiation. In grafting, auxin promotes callus tissue formation, which joins the surfaces of the graft together. In micropropagation, different PGRs are used to promote multiplication and then rooting of new plantlets. In the tissue-culturing of plant cells, PGRs are used to produce callus growth, multiplication, and rooting.

Seed dormancy

Plant hormones affect seed germination and dormancy by acting on different parts of the seed.

Embryo dormancy is characterized by a high ABA:GA ratio, whereas the seed has high abscisic acid sensitivity and low GA sensitivity. In order to release the seed from this type of dormancy and initiate seed germination, an alteration in hormone biosynthesis and degradation toward a low ABA/GA ratio, along with a decrease in ABA sensitivity and an increase in GA sensitivity, must occur.

ABA controls embryo dormancy, and GA embryo germination. Seed coat dormancy involves the mechanical restriction of the seed coat. This, along with a low embryo growth potential, effectively produces seed dormancy. GA releases this dormancy by increasing the embryo growth potential, and/or weakening the seed coat so the radical of the seedling can break through the seed coat. Different types of seed coats can be made up of living or dead cells, and both types can be influenced by hormones; those composed of living cells are acted upon after seed formation, whereas the seed coats composed of dead cells can be influenced by hormones during the formation of the seed coat. ABA affects testa or seed coat growth characteristics, including thickness, and effects the GA-mediated embryo growth potential. These conditions and effects occur during the formation of the seed, often in response to environmental conditions. Hormones also mediate endosperm dormancy: Endosperm in most seeds is composed of living tissue that can actively respond to hormones generated by the embryo. The endosperm often acts as a barrier to seed germination, playing a part in seed coat dormancy or in the germination process. Living cells respond to and also affect the ABA:GA ratio, and mediate cellular sensitivity; GA thus increases the embryo growth potential and can promote endosperm weakening. GA also affects both ABA-independent and ABA-inhibiting processes within the endosperm.

Human use

Salicylic acid

Willow bark has been used for centuries as a painkiller. The active ingredient in willow bark that provides these effects is the hormone salicylic acid (SA). In 1899, the pharmaceutical company Bayer began marketing a derivative of SA as the drug aspirin. In addition to its use as a painkiller, SA is also used in topical treatments of several skin conditions, including acne, warts and psoriasis. Another derivative of SA, sodium salicylate has been found to suppress proliferation of lymphoblastic leukemia, prostate, breast, and melanoma human cancer cells.

Jasmonic acid

Jasmonic acid (JA) can induce death in lymphoblastic leukemia cells. Methyl jasmonate (a derivative of JA, also found in plants) has been shown to inhibit proliferation in a number of cancer cell lines, although there is still debate over its use as an anti-cancer drug, due to its potential negative effects on healthy cells.

Color theory

From Wikipedia, the free encyclopedia
https://en.wikipedia.org/wiki/Color_theory

In the visual arts, color theory is a body of practical guidance to color mixing and the visual effects of a specific color combination. Color terminology based on the color wheel and its geometry separates colors into primary color, secondary color, and tertiary color. Understanding color theory dates to antiquity. Aristotle (d. 322 BCE) and Claudius Ptolemy (d. 168 CE) already discussed which and how colors can be produced by mixing other colors. The influence of light on color was investigated and revealed further by al-Kindi (d. 873) and Ibn al-Haytham (d.1039). Ibn Sina (d. 1037), Nasir al-Din al-Tusi (d. 1274) and Robert Grosseteste (d. 1253) discovered that contrary to the teachings of Aristotle, there are multiple color paths to get from black to white. More modern approaches to color theory principles can be found in the writings of Leone Battista Alberti (c. 1435) and the notebooks of Leonardo da Vinci (c. 1490). A formalization of "color theory" began in the 18th century, initially within a partisan controversy over Isaac Newton's theory of color (Opticks, 1704) and the nature of primary colors. From there it developed as an independent artistic tradition with only superficial reference to colorimetry and vision science.

The application of color theory ranges from ancient Egyptian uses to modern commercial advertising. Colors affect our mood and perception. In ancient civilizations, color was explored for its healing properties. Phototherapy (light therapy) was practiced in ancient Egypt, Greece, China and India. The Egyptians utilized sunlight as well as color for healing. Color has been investigated for its healing potential since 2000 BC.

Classifications

Color can be classified according to

  1. Warm and Cold
  2. Receding and Advancing
  3. Positive and negative
  4. Subtractive and additive

Color abstractions

Additive color mixing (such as in a computer)
 
Subtractive color mixing (such as in a printer)

The foundations of pre-20th-century color theory were built around "pure" or ideal colors, characterized by different sensory experiences rather than attributes of the physical world. This has led to a number of inaccuracies in traditional color theory principles that are not always remedied in modern formulations.

Another issue has been the tendency to describe color effects holistically or categorically, for example as a contrast between "yellow" and "blue" conceived as generic colors, when most color effects are due to contrasts on three relative attributes which define all colors:

  1. Value (light vs. dark, or white vs. black),
  2. Chroma [saturation, purity, strength, intensity] (intense vs. dull), and
  3. Hue (e.g. the name of the color family: red, yellow, green, cyan, blue, magenta).

The visual impact of "yellow" vs. "blue" hues in visual design depends on the relative lightness and saturation of the hues.

These confusions are partly historical and arose in scientific uncertainty about the color perception that was not resolved until the late 19th-century when the artistic notions were already entrenched. They also arise from the attempt to describe the highly contextual and flexible behavior of color perception in terms of abstract color sensations that can be generated equivalently by any visual media.

Many historical "color theorists" have assumed that three "pure" primary colors can mix into all possible colors, and any failure of specific paints or inks to match this ideal performance is due to the impurity or imperfection of the colorants. In reality, only imaginary "primary colors" used in colorimetry can "mix" or quantify all visible (perceptually possible) colors; but to do this, these imaginary primaries are defined as lying outside the range of visible colors; i.e., they cannot be seen. Any three real "primary" colors of light, paint or ink can mix only a limited range of colors, called a gamut, which is always smaller (contains fewer colors) than the full range of colors humans can perceive.

Historical background

Color theory was originally formulated in terms of three "primary" or "primitive" colors—red, yellow and blue (RYB)—because these colors were believed capable of mixing all other colors.

Goethe's color wheel from his 1810 Theory of Colours

The RYB primary colors became the foundation of 18th-century theories of color vision, as the fundamental sensory qualities that are blended in the perception of all physical colors, and conversely, in the physical mixture of pigments or dyes. These theories were enhanced by 18th-century investigations of a variety of purely psychological color effects, in particular the contrast between "complementary" or opposing hues that are produced by color afterimages and in the contrasting shadows in colored light. These ideas and many personal color observations were summarized in two founding documents in color theory: the Theory of Colours (1810) by the German poet Johann Wolfgang von Goethe, and The Law of Simultaneous Color Contrast (1839) by the French industrial chemist Michel Eugène Chevreul. Charles Hayter published A New Practical Treatise on the Three Primitive Colours Assumed as a Perfect System of Rudimentary Information (London 1826), in which he described how all colors could be obtained from just three.

Page from 1826 A New Practical Treatise on the Three Primitive Colours Assumed as a Perfect System of Rudimentary Information by Charles Hayter

Subsequently, German and English scientists established in the late 19th century that color perception is best described in terms of a different set of primary colors—red, green and blue-violet (RGB)—modeled through the additive mixture of three monochromatic lights. Subsequent research anchored these primary colors in the differing responses to light by three types of color receptors or cones in the retina (trichromacy). On this basis the quantitative description of the color mixture or colorimetry developed in the early 20th century, along with a series of increasingly sophisticated models of color space and color perception, such as the opponent process theory.

Across the same period, industrial chemistry radically expanded the color range of lightfast synthetic pigments, allowing for substantially improved saturation in color mixtures of dyes, paints, and inks. It also created the dyes and chemical processes necessary for color photography. As a result, three-color printing became aesthetically and economically feasible in mass printed media, and the artists' color theory was adapted to primary colors most effective in inks or photographic dyes: cyan, magenta, and yellow (CMY). (In printing, dark colors are supplemented by black ink, known as the CMYK system; in both printing and photography, white is provided by the color of the paper.) These CMY primary colors were reconciled with the RGB primaries, and subtractive color mixing with additive color mixing, by defining the CMY primaries as substances that absorbed only one of the retinal primary colors: cyan absorbs only red (−R+G+B), magenta only green (+R−G+B), and yellow only blue-violet (+R+G−B). It is important to add that the CMYK, or process, color printing is meant as an economical way of producing a wide range of colors for printing, but is deficient in reproducing certain colors, notably orange and slightly deficient in reproducing purples. A wider range of colors can be obtained with the addition of other colors to the printing process, such as in Pantone's Hexachrome printing ink system (six colors), among others.

Munsell's 1905 color system represented as a three-dimensional solid showing all three color making attributes: lightness, saturation and hue.

For much of the 19th-century artistic color theory either lagged behind scientific understanding or was augmented by science books written for the lay public, in particular Modern Chromatics (1879) by the American physicist Ogden Rood, and early color atlases developed by Albert Munsell (Munsell Book of Color, 1915, see Munsell color system) and Wilhelm Ostwald (Color Atlas, 1919). Major advances were made in the early 20th century by artists teaching or associated with the German Bauhaus, in particular Wassily Kandinsky, Johannes Itten, Faber Birren and Josef Albers, whose writings mix speculation with an empirical or demonstration-based study of color design principles.

Traditional color theory

Complementary colors

Chevreul's 1855 "chromatic diagram" based on the RYB color model, showing complementary colors and other relationships
 

For the mixing of colored light, Isaac Newton's color wheel is often used to describe complementary colors, which are colors that cancel each other's hue to produce an achromatic (white, gray or black) light mixture. Newton offered as a conjecture that colors exactly opposite one another on the hue circle cancel out each other's hue; this concept was demonstrated more thoroughly in the 19th century. An example of complementary colors would be red and green

A key assumption in Newton's hue circle was that the "fiery" or maximum saturated hues are located on the outer circumference of the circle, while achromatic white is at the center. Then the saturation of the mixture of two spectral hues was predicted by the straight line between them; the mixture of three colors was predicted by the "center of gravity" or centroid of three triangle points, and so on.

Primary, secondary, and tertiary colors of the RYB color model

According to traditional color theory based on subtractive primary colors and the RYB color model, yellow mixed with purple, orange mixed with blue, or red mixed with green produces an equivalent gray and are the painter's complementary colors. These contrasts form the basis of Chevreul's law of color contrast: colors that appear together will be altered as if mixed with the complementary color of the other color. A piece of yellow fabric placed on a blue background will appear tinted orange because orange is the complementary color to blue.

However, when complementary colors are chosen based on the definition by light mixture, they are not the same as the artists' primary colors. This discrepancy becomes important when color theory is applied across media. Digital color management uses a hue circle defined according to additive primary colors (the RGB color model), as the colors in a computer monitor are additive mixtures of light, not subtractive mixtures of paints.

One reason the artist's primary colors work at all is due to the imperfect pigments being used have sloped absorption curves, and change color with concentration. A pigment that is pure red at high concentrations can behave more like magenta at low concentrations. This allows it to make purples that would otherwise be impossible. Likewise, a blue that is ultramarine at high concentrations appears cyan at low concentrations, allowing it to be used to mix green. Chromium red pigments can appear orange, and then yellow, as the concentration is reduced. It is even possible to mix very low concentrations of the blue mentioned and the chromium red to get a greenish color. This works much better with oil colors than it does with watercolors and dyes.

The old primaries depend on sloped absorption curves and pigment leakages to work, while newer scientifically derived ones depend solely on controlling the amount of absorption in certain parts of the spectrum.

Another reason the correct primary colors were not used by early artists is they were not available as durable pigments. Modern methods in chemistry were needed to produce them.

Warm vs. cool colors

The distinction between "warm" and "cool" colors has been important since at least the late 18th century. The difference (as traced by etymologies in the Oxford English Dictionary), seems related to the observed contrast in landscape light, between the "warm" colors associated with daylight or sunset, and the "cool" colors associated with a gray or overcast day. Warm colors are often said to be hues from red through yellow, browns, and tans included; cool colors are often said to be the hues from blue-green through blue violet, most grays included. There is a historical disagreement about the colors that anchor the polarity, but 19th-century sources put the peak contrast between red-orange and greenish-blue.

Color theory has described perceptual and psychological effects to this contrast. Warm colors are said to advance or appear more active in a painting, while cool colors tend to recede; used in interior design or fashion, warm colors are said to arouse or stimulate the viewer, while cool colors calm and relax. Most of these effects, to the extent they are real, can be attributed to the higher saturation and lighter value of warm pigments in contrast to cool pigments; brown is a dark, unsaturated warm color that few people think of as visually active or psychologically arousing.

The traditional warm/cool association of a color is reversed relative to the color temperature of a theoretical radiating black body; the hottest stars radiate blue (cool) light, and the coolest radiate red (warm) light.

The hottest radiating bodies (e.g. stars) have a "cool" color, while the less hot bodies radiate with a "warm" color. (image is in Kelvin scale)
 
Doppler redshift for receding and blueshift for advancing

This contrast is further seen in the psychological associations of colors with the Doppler effect seen in astronomical objects. Traditional psychological associations, where warm colors are associated with advancing objects and cool colors with receding objects, are directly opposite those seen in astrophysics, where stars or galaxies moving towards our viewpoint on Earth are blueshifted (advancing) and stars or galaxies moving away from Earth are redshifted (receding).

Achromatic colors

Any color that lacks strong chromatic content is said to be unsaturated, achromatic, near-neutral, or neutral. Near neutrals include browns, tans, pastels, and darker colors. Near neutrals can be of any hue or lightness. Pure achromatic, or neutral colors include black, white and all grays.

Near neutrals are obtained by mixing pure colors with white, black or grey, or by mixing two complementary colors. In color theory, neutral colors are easily modified by adjacent more saturated colors and they appear to take on the hue complementary to the saturated color; e.g., next to a bright red couch, a gray wall will appear distinctly greenish, This is a property of human vision.

Black and white have long been known to combine "well" with almost any other colors; black decreases the apparent saturation or brightness of colors paired with it and white shows off all hues to equal effect.

Tints and shades

When mixing colored light (additive color models), the achromatic mixture of spectrally balanced red, green, and blue (RGB) is always white, not gray or black. When we mix colorants, such as the pigments in paint mixtures, a color is produced which is always darker and lower in chroma, or saturation, than the parent colors. This moves the mixed color toward a neutral color—a gray or near-black. Lights are made brighter or dimmer by adjusting their brightness, or energy level; in painting, lightness is adjusted through mixture with white, black, or a color's complement.

It is common among some painters to darken a paint color by adding black paint—producing colors called shades—or lighten a color by adding white—producing colors called tints. However, it is not always the best way for representational painting, as an unfortunate result is for colors to also shift in hue. For instance, darkening a color by adding black can cause colors such as yellows, reds, and oranges, to shift toward the greenish or bluish part of the spectrum. Lightening a color by adding white can cause a shift towards blue when mixed with reds and oranges. Another practice when darkening a color is to use its opposite, or complementary, color (e.g. purplish-red added to yellowish-green) in order to neutralize it without a shift in hue, and darken it if the additive color is darker than the parent color. When lightening a color this hue shift can be corrected with the addition of a small amount of an adjacent color to bring the hue of the mixture back in line with the parent color (e.g. adding a small amount of orange to a mixture of red and white will correct the tendency of this mixture to shift slightly towards the blue end of the spectrum).

Split primary colors

In painting and other visual arts, two-dimensional color wheels or three-dimensional color solids are used as tools to teach beginners the essential relationships between colors. The organization of colors in a particular color model depends on the purpose of that model: some models show relationships based on human color perception, whereas others are based on the color mixing properties of a particular medium such as a computer display or set of paints.

This system is still popular among contemporary painters, as it is basically a simplified version of Newton's geometrical rule that colors closer together on the hue circle will produce more vibrant mixtures. However, with the range of contemporary paints available, many artists simply add more paints to their palette as desired for a variety of practical reasons. For example, they may add a scarlet, purple and/or green paint to expand the mixable gamut; and they include one or more dark colors (especially "earth" colors such as yellow ochre or burnt sienna) simply because they are convenient to have premixed. Printers commonly augment a CMYK palette with spot (trademark specific) ink colors.

Color harmony

It has been suggested that "Colors seen together to produce a pleasing affective response are said to be in harmony". However, color harmony is a complex notion because human responses to color are both affective and cognitive, involving emotional response and judgment. Hence, our responses to color and the notion of color harmony is open to the influence of a range of different factors. These factors include individual differences (such as age, gender, personal preference, affective state, etc.) as well as cultural, sub-cultural, and socially-based differences which gives rise to conditioning and learned responses about color. In addition, context always has an influence on responses about color and the notion of color harmony, and this concept is also influenced by temporal factors (such as changing trends) and perceptual factors (such as simultaneous contrast) which may impinge on human response to color. The following conceptual model illustrates this 21st-century approach to color harmony:

wherein color harmony is a function (f) of the interaction between color/s (Col 1, 2, 3, …, n) and the factors that influence positive aesthetic response to color: individual differences (ID) such as age, gender, personality and affective state; cultural experiences (CE), the prevailing context (CX) which includes setting and ambient lighting; intervening perceptual effects (P) and the effects of time (T) in terms of prevailing social trends.

Georg Christoph Lichtenberg. Göttingen, 1775, plate III.

In addition, given that humans can perceive over 2.8 million different colors, it has been suggested that the number of possible color combinations is virtually infinite thereby implying that predictive color harmony formulae are fundamentally unsound. Despite this, many color theorists have devised formulae, principles or guidelines for color combination with the aim being to predict or specify positive aesthetic response or "color harmony".

Color wheel models have often been used as a basis for color combination principles or guidelines and for defining relationships between colors. Some theorists and artists believe juxtapositions of complementary color will produce strong contrast, a sense of visual tension as well as "color harmony"; while others believe juxtapositions of analogous colors will elicit a positive aesthetic response. Color combination guidelines (or formulas) suggest that colors next to each other on the color wheel model (analogous colors) tend to produce a single-hued or monochromatic color experience and some theorists also refer to these as "simple harmonies".

In addition, split complementary color schemes usually depict a modified complementary pair, with instead of the "true" second color being chosen, a range of analogous hues around it are chosen, i.e. the split complements of red are blue-green and yellow-green. A triadic color scheme adopts any three colors approximately equidistant around a color wheel model. Feisner and Mahnke are among a number of authors who provide color combination guidelines in greater detail.

Ignaz Schiffermüller, Versuch eines Farbensystems (Vienna, 1772), plate I.

Color combination formulae and principles may provide some guidance but have limited practical application. This is due to the influence of contextual, perceptual, and temporal factors which will influence how color/s are perceived in any given situation, setting, or context. Such formulae and principles may be useful in fashion, interior and graphic design, but much depends on the tastes, lifestyle, and cultural norms of the viewer or consumer.

As early as the ancient Greek philosophers, many theorists have devised color associations and linked particular connotative meanings to specific colors. However, connotative color associations and color symbolism tends to be culture-bound and may also vary across different contexts and circumstances. For example, red has many different connotative and symbolic meanings from exciting, arousing, sensual, romantic, and feminine; to a symbol of good luck; and also acts as a signal of danger. Such color associations tend to be learned and do not necessarily hold irrespective of individual and cultural differences or contextual, temporal or perceptual factors. It is important to note that while color symbolism and color associations exist, their existence does not provide evidential support for color psychology or claims that color has therapeutic properties.

Monochromatic

The monochromatic formula chooses only one color (or hue). Variations of the color are created by changing the value and saturation of the color. Since only one hue is used, the color and its variations are guaranteed to work.

Current status

Color theory has not developed an explicit explanation of how specific media affect color appearance: colors have always been defined in the abstract, and whether the colors were inks or paints, oils or watercolors, transparencies or reflecting prints, computer displays or movie theaters, was not considered especially relevant. Josef Albers investigated the effects of relative contrast and color saturation on the illusion of transparency, but this is an exception to the rule.

Moon

From Wikipedia, the free encyclopedia https://en.wikipedia.org/wiki/Moon   Near side of the Moon , lunar ...