Photosynthesis is particularly sensitive to the effects of water deficiency. Plants’ resistance to
water deficiency yields metabolic changes along with functional and structural
rearrangements of photosynthesizing apparatus. Photosynthesis of higher plants decreases
with the reduction in the relative water content (RWC) and leaf water potential. Lower photosynthesis rate is a usual effect of water stress in plants and has been attributed
primarily to stomatal limitation and secondarily to metabolic impairment. However,
metabolic impairment is the more complex phenomenon than the stomatal limitation
though the relative importance of stomatal or metabolic inhibitions is unclear. Some studies
blamed stomatal closure for the inhibition of C4 photosynthesis under water stress while
others concluded that non-stomatal factors play the major role.
The photosynthesis rate of leaves in both C3 and C4 plants decrease under the drought
conditions. Evidence indicates that C4 photosynthesis is more sensitive to water stress and
C4 plants, such as corn (Zea mays L.) are more susceptible to water deficiency than C3 plants,
such as wheat. It explains the predominance of C4 plants in hot, arid regions - areas prone to
frequent drought. C3 and C4 plants are alike in the basic process of photosynthesis like
Calvin cycle and electron transport chain components, yet significant differences exist
between them, which make their responses to water stress differ at a number of levels.
Photosynthesis is particularly sensitive to the effects of water deficiency. Plants’ resistance towater deficiency yields metabolic changes along with functional and structuralrearrangements of photosynthesizing apparatus. Photosynthesis of higher plants decreaseswith the reduction in the relative water content (RWC) and leaf water potential. Lower photosynthesis rate is a usual effect of water stress in plants and has been attributedprimarily to stomatal limitation and secondarily to metabolic impairment. However,metabolic impairment is the more complex phenomenon than the stomatal limitationthough the relative importance of stomatal or metabolic inhibitions is unclear. Some studiesblamed stomatal closure for the inhibition of C4 photosynthesis under water stress whileothers concluded that non-stomatal factors play the major role.The photosynthesis rate of leaves in both C3 and C4 plants decrease under the droughtconditions. Evidence indicates that C4 photosynthesis is more sensitive to water stress andC4 plants, such as corn (Zea mays L.) are more susceptible to water deficiency than C3 plants,such as wheat. It explains the predominance of C4 plants in hot, arid regions - areas prone tofrequent drought. C3 and C4 plants are alike in the basic process of photosynthesis likeCalvin cycle and electron transport chain components, yet significant differences existbetween them, which make their responses to water stress differ at a number of levels.
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