Abiotic Stress
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Abiotic Stress

Abiotic stress is 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 living disturbances such as fungi or harmful insects, abiotic stress factors, or stressors, are naturally occurring, often intangible and inanimate factors such as intense sunlight, temperature 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, if not solely 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]



The most basic stressors include:

Lesser-known stressors generally occur on a smaller scale. They include: poor edaphic conditions like rock content and pH levels, high radiation, compaction, contamination, and other, highly specific conditions like rapid rehydration during seed germination.[5]




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]






In plants


The plant responses to stress are dependent on the tissue or organ affected by the stress. For example, transcriptional responses to stress are tissue or cell specific in roots and are quite different depending on the stress involved.[10]

One of the primary responses to abiotic stress such as high salinity is the disruption of the Na+/K+ ratio in the cytoplasm of the plant cell. High concentrations of Na+, for example, can decrease the capacity for the plant to take up water and also alter enzyme and transporter functions. Evolved adaptations to efficiently restore cellular ion homeostasis has led to a wide variety of stress tolerant plants.[11]



Rice (Oryza sativa) is a classic example. Rice is a staple food throughout the world, especially in China and India. Rice plants experience different types of abiotic stresses, like drought and high salinity. These stress conditions have a negative impact on rice production. Genetic diversity has been studied among several rice varieties with different genotypes using molecular markers.

Serpentine soils (media with low concentrations of nutrients and high concentrations of heavy metals) can be a source of abiotic stress. Initially, the absorption of toxic metal ions is limited by cell membrane exclusion. Ions that are absorbed into tissues are sequestered in cell vacuoles. This sequestration mechanism is facilitated by proteins on the vacuole membrane.[13]

Chemical priming has been proposed to increase tolerance to abiotic stresses in crop plants. In this method, which is analogous to vaccination, stress-inducing chemical agents are introduced to the plant in brief doses so that the plant begins preparing defense mechanisms. Thus, when the abiotic stress occurs, the plant has already prepared defense mechanisms that can be activated faster and increase tolerance.[14]

Salt stress in plants

Soil salinization, the accumulation of water-soluble salts to levels that negatively impact plant production, is a global phenomenon affecting approximately 831 million hectares of land.[15] More specifically, the phenomenon threatens 19.5% of the world's irrigated agricultural land and 2.1% of the world's non-irrigated (dry-land) agricultural lands.[16] High soil salinity content can be harmful to plants because water-soluble salts can alter osmotic potential gradients and consequently inhibit many cellular functions.[16][17] For example, high soil salinity content can inhibit the process of photosynthesis by limiting a plant's water uptake; high levels of water-soluble salts in the soil can decrease the osmotic potential of the soil and consequently decrease the difference in water potential between the soil and the plant's roots, thereby limiting electron flow from H2O to P680 in Photosystem II's reaction center.[18]

Over generations, many plants have mutated and built different mechanisms to counter salinity effects.[16] A good combatant of salinity in plants is the hormone ethylene. Ethylene is known for regulating plant growth and development and dealing with stress conditions. Many central membrane proteins in plants, such as ETO2, ERS1 and EIN2, are used for ethylene signaling in many plant growth processes. Mutations in these proteins can lead to heightened salt sensitivity and can limit plant growth. The effects of salinity has been studied on Arabidopsis plants that have mutated ERS1, ERS2, ETR1, ETR2 and EIN4 proteins. These proteins are used for ethylene signaling again certain stress conditions, such as salt and the ethylene precursor ACC is used to suppress any sensitivity to the salt stress.[19]

Phosphate starvation in plants

Phosphorus (P) is an essential macronutrient required for plant growth and development, but most of the world's soil is limited in this important plant nutrient. Plants can utilize P mainly in the form if soluble inorganic phosphate (Pi) but are subjected to abiotic stress of P-limitation when there is not sufficient soluble PO4 available in the soil. Phosphorus forms insoluble complexes with Ca and Mg in alkaline soils and Al and Fe in acidic soils that makes it unavailable for plant roots. When there is limited bioavailable P in the soil, plants show extensive abiotic stress phenotype such as short primary roots and more lateral roots and root hairs to make more surface available for Pi absorption, exudation of organic acids and phosphatase to release Pi from complex P containing molecules and make it available for growing plants organs.[20] It has been shown that PHR1, a MYB - related transcription factor is a master regulator of P-starvation response in plants.[21][22] PHR1 also has been shown to regulate extensive remodeling of lipids and metabolites during phosphorus limitation stress[22][23]

Drought Stress

Drought stress is one of the main causes of crop loss within the agricultural world. This is due to water's necessity in so many fundamental processes in plant growth.[24] It has become especially important in recent years to find a way to combat drought stress. A decrease in precipitation and subsequent increase in drought are extremely likely in the future due to an increase in global warming.[25] Plants have come up with many mechanisms and adaptations to try and deal with drought stress. One of the leading ways that plants combat drought stress is by closing their stomates. A key hormone regulating stomatal opening and closing is abscisic acid (ABA). Synthesis of ABA causes the ABA to bind to receptors. This binding then effects the opening of ion channels thereby decreasing turgor pressure in the stomata and causing them to close. Recent studies, by Gonzalez-Villagra, et al., showed how ABA levels increased in drought-stressed plants (2018). They showed that when plants were placed in a stressful situation they produced more ABA to try and conserve any water they had in their leaves.[24] Another extremely important factor in dealing with drought stress and regulating the uptake and export of water is aquaporins (AQPs). AQPs are integral membrane proteins that make up channels. These channel's main job is the transport of water and other necessary solutes. AQPs are both transcriptionally and post transcriptionally regulated by many different factors such as ABA, GA3, pH and Ca2+ and the specific levels of AQPs in certain parts of the plant, such as roots or leaves, helps to draw as much water into the plant as possible.[26] By understanding both the mechanism of AQPs and the hormone ABA, scientists will be better able to produce drought resistant plants in the future.

One interesting thing that has been found in plants that are consistently exposed to drought, is their ability to form a sort of "memory". In a study by Tombesi et al., they found plants who had previously been exposed to drought were able to come up with a sort of strategy to minimize water loss and decrease water use.[25] They found that plants who were exposed to drought conditions actually changed they way the regulated their stomates and what they called "hydraulic safety margin" so as to decrease the venerability of the plant. By changing the regulation of stomata and subsequently the transpiration, plants were able to function better in situations where the availability of water decreased.[25]

In animals



In endangered species


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


  1. ^ "Abiotic Stress". Biology Online. Archived from the original on 13 June 2008. Retrieved .
  2. ^ a b Vinebrooke, Rolf D.; et al. (2004). "Impacts of multiple stressors on biodiversity and ecosystem functioning: the role of species co-tolerance". OIKOS. 104 (3): 451-457. doi:10.1111/j.0030-1299.2004.13255.x.
  3. ^ Gao, Ji-Ping; et al. (2007). "Understanding Abiotic Stress Tolerance Mechanisms: Recent Studies on Stress Response in Rice". Journal of Integrative Plant Biology. 49 (6): 742-750. doi:10.1111/j.1744-7909.2007.00495.x.
  4. ^ a b Mittler, Ron (2006). "Abiotic stress, the field environment and stress combination". Trends in Plant Science. 11 (1): 15-19. doi:10.1016/j.tplants.2005.11.002. PMID 16359910.
  5. ^ a b c d e f g Palta, Jiwan P. and Farag, Karim. "Methohasds 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.
  6. ^ a b Wolfe, A. "Patterns of biodiversity." Ohio State University, 2007.
  7. ^ a b c Brussaard, Lijbert; de Ruiter, Peter C.; Brown, George G. (2007). "Soil biodiversity for agricultural sustainability". Agriculture, Ecosystems and Environment. 121 (3): 233-244. doi:10.1016/j.agee.2006.12.013.
  8. ^ a b Roelofs, D.; et al. (2008). "Functional ecological genomics to demonstrate general and specific responses to abiotic stress". Functional Ecology. 22: 8-18. doi:10.1111/j.1365-2435.2007.01312.x.
  9. ^ Wang, W.; Vinocur, B.; Altman, A. (2007). "Plant responses to drought, salinity and extreme temperatures towards genetic engineering for stress tolerance". Planta. 218 (1): 1-14. doi:10.1007/s00425-003-1105-5. PMID 14513379.
  10. ^ Cramer, Grant R; Urano, Kaoru; Delrot, Serge; Pezzotti, Mario; Shinozaki, Kazuo (2011-11-17). "Effects of abiotic stress on plants: a systems biology perspective". BMC Plant Biology. 11: 163. doi:10.1186/1471-2229-11-163. ISSN 1471-2229. PMC 3252258. PMID 22094046.
  11. ^ Conde, Artur (2011). "Membrane Transport, Sensing and Signaling in Plant Adaptation to Environmental Stress" (PDF). Plant & Cell Physiology. 52 (9): 1583-1602. doi:10.1093/pcp/pcr107. PMID 21828102 – via Google Scholar.
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  15. ^ Martinez-Beltran J, Manzur CL. (2005). Overview of salinity problems in the world and FAO strategies to address the problem. Proceedings of the international salinity forum, Riverside, California, April 2005, 311-313.
  16. ^ a b c Neto, Azevedo; De, André Dias; Prisco, José Tarquinio; Enéas-Filho, Joaquim; Lacerda, Claudivan Feitosa de; Silva, José Vieira; Costa, Paulo Henrique Alves da; Gomes-Filho, Enéas (2004-04-01). "Effects of salt stress on plant growth, stomatal response and solute accumulation of different maize genotypes". Brazilian Journal of Plant Physiology. 16 (1): 31-38. doi:10.1590/S1677-04202004000100005. ISSN 1677-0420.
  17. ^ Zhu, J.-K. (2001). Plant Salt Stress. eLS.
  18. ^ Lu. Congming, A. Vonshak. (2002). Effects of salinity stress on photosystem II function in cyanobacterial Spirulina platensis cells. Physiol. Plant 114 405-413.
  19. ^ Lei, Gang; Shen, Ming; Li, Zhi-Gang; Zhang, Bo; Duan, Kai-Xuan; Wang, Ning; Cao, Yang-Rong; Zhang, Wan-Ke; Ma, Biao (2011-10-01). "EIN2 regulates salt stress response and interacts with a MA3 domain-containing protein ECIP1 in Arabidopsis". Plant, Cell & Environment. 34 (10): 1678-1692. doi:10.1111/j.1365-3040.2011.02363.x. ISSN 1365-3040.
  20. ^ Raghothama, K. G. (1999-01-01). "Phosphate Acquisition". Annual Review of Plant Physiology and Plant Molecular Biology. 50 (1): 665-693. doi:10.1146/annurev.arplant.50.1.665. PMID 15012223.
  21. ^ Rubio, Vicente; Linhares, Francisco; Solano, Roberto; Martín, Ana C.; Iglesias, Joaquín; Leyva, Antonio; Paz-Ares, Javier (2001-08-15). "A conserved MYB transcription factor involved in phosphate starvation signaling both in vascular plants and in unicellular algae". Genes & Development. 15 (16): 2122-2133. doi:10.1101/gad.204401. ISSN 0890-9369. PMC 312755. PMID 11511543.
  22. ^ a b Pant, Bikram Datt; Burgos, Asdrubal; Pant, Pooja; Cuadros-Inostroza, Alvaro; Willmitzer, Lothar; Scheible, Wolf-Rüdiger (2015-04-01). "The transcription factor PHR1 regulates lipid remodeling and triacylglycerol accumulation in Arabidopsis thaliana during phosphorus starvation". Journal of Experimental Botany. 66 (7): 1907-1918. doi:10.1093/jxb/eru535. ISSN 0022-0957. PMC 4378627. PMID 25680792.
  23. ^ Pant, Bikram-Datt; Pant, Pooja; Erban, Alexander; Huhman, David; Kopka, Joachim; Scheible, Wolf-Rüdiger (2015-01-01). "Identification of primary and secondary metabolites with phosphorus status-dependent abundance in Arabidopsis, and of the transcription factor PHR1 as a major regulator of metabolic changes during phosphorus limitation". Plant, Cell & Environment. 38 (1): 172-187. doi:10.1111/pce.12378. ISSN 1365-3040. PMID 24894834.
  24. ^ a b González-Villagra, Jorge; Rodrigues-Salvador, Acácio; Nunes-Nesi, Adriano; Cohen, Jerry D.; Reyes-Díaz, Marjorie M. (March 2018). "Age-related mechanism and its relationship with secondary metabolism and abscisic acid in Aristotelia chilensis plants subjected to drought stress". Plant Physiology and Biochemistry. 124: 136-145. doi:10.1016/j.plaphy.2018.01.010. ISSN 0981-9428. PMID 29360623.
  25. ^ a b c Tombesi, Sergio; Frioni, Tommaso; Poni, Stefano; Palliotti, Alberto (June 2018). "Effect of water stress "memory" on plant behavior during subsequent drought stress". Environmental and Experimental Botany. 150: 106-114. doi:10.1016/j.envexpbot.2018.03.009. ISSN 0098-8472.
  26. ^ Zargar, Sajad Majeed; Nagar, Preeti; Deshmukh, Rupesh; Nazir, Muslima; Wani, Aijaz Ahmad; Masoodi, Khalid Zaffar; Agrawal, Ganesh Kumar; Rakwal, Randeep (October 2017). "Aquaporins as potential drought tolerance inducing proteins: Towards instigating stress tolerance". Journal of Proteomics. 169: 233-238. doi:10.1016/j.jprot.2017.04.010. ISSN 1874-3919.
  27. ^ Goncalves-Alvim, Silmary J.; Fernandez, G. Wilson (2001). "Biodiversity of galling insects: historical, community and habitat effects in four neotropical savannas". Biodiversity and Conservation. 10: 79-98. doi:10.1023/a:1016602213305.




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