Abiotic stress: Difference between revisions
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The most obvious detriment concerning abiotic stress involves farming. It has been claimed by one study that abiotic stress causes the most crop loss of any other factor and that most major crops are reduced in their yield by more than 50% from their potential yield.<ref>Wang, W., Vinocur, B. and Altman, A. “Plant responses to drought, salinity and extreme temperatures towards genetic engineering for stress tolerance.” Planta 218: 1-14, 2007.</ref> It has also been speculated that this yield reduction will only worsen with the dramatic climate changes expected in the future.<ref name = "Lane">Lane, A. and A. Jarvis. “Changes in Climate will modify the Geography of Crop Suitability: Agricultural Biodiversity can help with Adaptation.” eJournal 4(1): 1-12, 2007.</ref> |
The most obvious detriment concerning abiotic stress involves farming. It has been claimed by one study that abiotic stress causes the most crop loss of any other factor and that most major crops are reduced in their yield by more than 50% from their potential yield.<ref>Wang, W., Vinocur, B. and Altman, A. “Plant responses to drought, salinity and extreme temperatures towards genetic engineering for stress tolerance.” Planta 218: 1-14, 2007.</ref> It has also been speculated that this yield reduction will only worsen with the dramatic climate changes expected in the future.<ref name = "Lane">Lane, A. and A. Jarvis. “Changes in Climate will modify the Geography of Crop Suitability: Agricultural Biodiversity can help with Adaptation.” eJournal 4(1): 1-12, 2007.</ref> |
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Because abiotic stress is widely considered a detrimental effect, the research on this branch of the issue is extensive. For more information on the harmful effects of abiotic stress, see the sections below on plants and animals. |
Because abiotic stress is widely considered a detrimental effect, the research on this branch of the issue is extensive. For more information on the harmful effects of abiotic stress, see the sections below on plants and animals. |
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==In animals== |
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For animals, the most stressful of all the abiotic stressors is heat. This is because many species are unable to regulate their internal body temperature. Even in the species that are able to regulate their own temperature, it is not always a completely accurate system. Temperature determines metabolic rates, heart rates, and other very important factors within the bodies of animals, so an extreme temperature change can easily distress the animal’s body. Animals can respond to extreme heat, for example, through natural heat acclimation or by burrowing into the ground to find a cooler space.<ref name="roel"/> |
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It is also possible to see in animals that a high genetic diversity is beneficial in providing resiliency against harsh abiotic stressors. This acts as a sort of stock room when a species is plagued by the perils of natural selection. A variety of galling insects are among the most specialized and diverse herbivores on the planet, and their extensive protections against abiotic stress factors have helped the insect in gaining that position of honor.<ref>Goncalves-Alvim, Silmary J. and G. Wilson Fernandez. “Biodiversity of galling insects: historical, community and habitat effects in four neotropical savannas.” Biodiversity and Conservation 10: 79–98, 2001.</ref> |
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==In endangered species== |
==In endangered species== |
Revision as of 09:30, 9 July 2011
Abiotic stress is defined as the negative impact of non-living factors on the living organisms in a specific environment.[1] The non-living variable must influence the environment beyond its normal range of variation to adversely affect the population performance or individual physiology of the organism in a significant way.[2] Whereas a biotic stress would include such living disturbances as fungi or harmful insects, abiotic stress factors, or stressors, are naturally occurring, often intangible, factors such as intense sunlight or wind that may cause harm to the plants and animals in the area affected. Abiotic stress is essentially unavoidable. Abiotic stress affects animals, but plants are especially dependent on environmental factors, so it is particularly constraining. Abiotic stress is the most harmful factor concerning the growth and productivity of crops worldwide.[3] Research has also shown that abiotic stressors are at their most harmful when they occur together, in combinations of abiotic stress factors.[4]
Examples of abiotic stress
Abiotic stress comes in many forms. The most common of the stressors are the easiest for people to identify, but there are many other, less recognizable abiotic stress factors which affect environments constantly. The most basic stressors include: high winds, extreme temperatures, drought, flood, and other natural disasters, such as tornados and wildfires. The lesser-known stressors generally occur on a smaller scale and so are less noticeable, but they include: poor edaphic conditions like rock content and pH, high radiation, compaction, contamination, and other, highly specific conditions like rapid rehydration during seed germination.[5]
Effects of abiotic stress
Abiotic stress, as a natural part of every ecosystem, will affect organisms in a variety of ways. Although these effects may be either beneficial or detrimental, the location of the area is crucial in determining the extent of the impact that abiotic stress will have. The higher the latitude of the area affected, the greater the impact of abiotic stress will be on that area. So, a taiga or boreal forest is at the mercy of whatever abiotic stress factors may come along, while tropical zones are much less susceptible to such stressors.[6]
Benefits
One example of a situation where abiotic stress plays a constructive role in an ecosystem is in natural wildfires. While they can be a human safety hazard, it is productive for these ecosystems to burn out every once in a while so that new organisms can begin to grow and thrive. Even though it is healthy for an ecosystem, a wildfire can still be considered an abiotic stressor, because it puts an obvious stress on individual organisms within the area. Every tree that is scorched and each bird nest that is devoured is a sign of the abiotic stress. On the larger scale, though, natural wildfires are positive manifestations of abiotic stress.[7] What also needs to be taken into account when looking for benefits of abiotic stress, is that one phenomenon may not affect an entire ecosystem in the same way. While a flood will kill most plants living low on the ground in a certain area, if there is rice there, it will thrive in the wet conditions. Another example of this is in, phytoplankton and zooplankton. The same types of conditions are usually considered stressful for these two types of organisms. They act very similarly when exposed to ultraviolet light and most toxins, but at elevated temperatures the phytoplankton reacts negatively, while the thermophilic zooplankton reacts positively to the increase in temperature. The two may be living in the same environment, but an increase in temperature of the area would prove stressful only for one of the organisms.[2] Lastly, abiotic stress has enabled species to grow, develop, and evolve, furthering natural selection as it picks out the weakest of a group of organisms. Both plants and animals have evolved mechanisms allowing them to survive extremes.[8]
Detriments
The most obvious detriment concerning abiotic stress involves farming. It has been claimed by one study that abiotic stress causes the most crop loss of any other factor and that most major crops are reduced in their yield by more than 50% from their potential yield.[9] It has also been speculated that this yield reduction will only worsen with the dramatic climate changes expected in the future.[10] Because abiotic stress is widely considered a detrimental effect, the research on this branch of the issue is extensive. For more information on the harmful effects of abiotic stress, see the sections below on plants and animals.
In endangered species
Biodiversity is determined by many things, and one of them is abiotic stress. If an environment is highly stressful, biodiversity tends to be low. If abiotic stress does not have a strong presence in an area, the biodiversity will be much higher.[7] This idea leads into the understanding of how abiotic stress and endangered species are related. It has been observed through a variety of environments that as the level of abiotic stress increases, the number of species decreases.[6] This means that species are more likely to become population threatened, endangered, and even extinct, when and where abiotic stress is especially harsh.
See also
References
- ^ "Abiotic Stress". Biology Online. Retrieved 2008-05-04.
- ^ a b Vinebrooke, Rolf D. et al. “Impacts of multiple stressors on biodiversity and ecosystem functioning: the role of species co-tolerance.” OIKOS 104: 451– 457, 2004.
- ^ Gao, Ji-Ping, et al. “Understanding Abiotic Stress Tolerance Mechanisms: Recent Studies on Stress Response in Rice.” Journal of Integrative Plant Biology 49 (6): 742−750, 2007.
- ^ Mittler, Ron. “Abiotic stress, the field environment and stress combination.” Trends in Plant Science 11(1): 15–19, 2006.
- ^ Palta, Jiwan P. and Farag, Karim. “Methods for enhancing plant health, protecting plants from biotic and abiotic stress related injuries and enhancing the recovery of plants injured as a result of such stresses.” United States Patent 7101828, September 2006.
- ^ a b Wolfe, A. “Patterns of biodiversity.” Ohio State University, 2007.
- ^ a b Brussaard, Lijbert, Peter C. de Ruiter, and George G. Brown. “Soil biodiversity for agricultural sustainability.” Agriculture, Ecosystems and Environment 121: 233–244, 2007.
- ^ Roelofs, D. et al. “Functional ecological genomics to demonstrate general and specific responses to abiotic stress.” Functional Ecology 22: 8–18, 2008.
- ^ Wang, W., Vinocur, B. and Altman, A. “Plant responses to drought, salinity and extreme temperatures towards genetic engineering for stress tolerance.” Planta 218: 1-14, 2007.
- ^ Lane, A. and A. Jarvis. “Changes in Climate will modify the Geography of Crop Suitability: Agricultural Biodiversity can help with Adaptation.” eJournal 4(1): 1-12, 2007.