Plants respond to environmental stresses such as drought, excessive salinity and low temperature

1400 WordsApr 23, 20196 Pages
Plants respond to environmental stresses such as drought, excessive salinity and low temperature through a wide variety of biochemical and physiological adaptive changes such as the accumulation of compatible solutes and synthesis of many regulatory proteins (Wu and Garg, 2003; Gong et al., 2005). It inhibits the photosynthesis of plants by causing changes in chlorophyll contents and components, damaging photosynthetic apparatus (Gong et al., 2005), reducing the net CO2 uptake by leaves because of stomatal closure (Cornic, 2000) or by decreasing the activities of enzymes in the Calvin cycle. All these changes have negative effects on the plant growth (Monakhova and Chernyadev, 2002). Drought-stressed plants exhibit poor growth and yield…show more content…
This reflects the ability of the species to keep a viable root system during water stress required for drought tolerance. The study further indicates that the drought tolerant clones allocated more resources towards building up biomass and support tissue. Compared to the control treatments, the proportionate dry weight of the clones increased under stress conditions. When plants are subjected to a similar stress, namely salinity, an increase in root growth in order to increase water influx is usually documented as a general response to drought. However, experimental evidence indicates that reduced root and increased shoot growth may improve tolerance by restricting the flux of toxic ions to the shoot and consequently by delaying the onset of the tolerance threshold (Maggio et al., 2007). Carrasco et al., 2002 reported that long term exposure to drought and the diurnal changes did not affect photosynthetic electron transport in non-nodulated plants of Casuarina equisetifolia. Water stress caused a decline in RWC, a reduction in height and total dry biomass. It also caused a greater biomass allocation towards roots to the detriment of shoots during initial periods in Casuarina glauca. After four months, these responses were progressively attenuated, indicating an increase over time in the tolerance to drought acquired by the species stressed seedlings (Albouchi et. al., 2003). Ahmed et al. (2007) reported

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