Two distinct strategies of cotton and soybean differing in leaf movement to perform photosynthesis under drought in the field

Abstract

This paper reports an experimental test of the hypothesis that cotton and soybean differing in leaf movement have distinct strategies to perform photosynthesis under drought. Cotton and soybean were exposed to two water regimes: drought stressed and well watered. Drought-stressed cotton and soybean had lower maximum CO 2 assimilation rates than well-watered (control) plants. Drought reduced the light saturation point and photorespiration of both speciesespecially in soybean. Area-based leaf nitrogen decreased in drought-stressed soybean but increased in drought-stressed cotton. Drought decreased PSII quantum yield (F PSII ) in soybean leaves, but increased F PSII in cotton leaves. Drought induced an increase in light absorbed by the PSII antennae that is dissipated thermally via DpHand xanthophylls-regulated processes in soybean leaves, but a decrease in cotton leaves. Soybean leaves appeared to have greater cyclic electron flow (CEF) around PSI than cotton leaves and drought further increased CEF in soybean leaves. In contrast, CEF slightly decreased in cotton under drought. These results suggest that the difference in leaf movement between cotton and soybean leaves gives rise to different strategies to perform photosynthesis and to contrasting photoprotective mechanisms for utilisation or dissipation of excess light energy. We suggest that soybean preferentially uses light-regulated non-photochemical energy dissipation, which may have been enhanced by the higher CEF in drought-stressed leaves. In contrast, cotton appears to rely on enhanced electron transport flux for light energy utilisation under drought, for example, in enhanced nitrogen assimilation.

Effects of water stress and rewatering on photosynthesis, root activity, and yield of cotton with drip irrigation under mulch

“…One explanation is that in the moderate water deficit treatment (i.e., V 2 ), most of the excitation energy in the photosynthetic apparatus was used for thermal dissipation after rewatering. Only a fraction of the excitation energy was delivered to the photochemical reaction center (Zhang et al 2011). This finding also suggests that moderate drought caused irreversible damage to the photosynthetic apparatus of cotton leaves.…”

The Role of Plants in the Effects of Global Change on Nutrient Availability and Stoichiometry in the Plant-Soil System

“…Drought increases the production of abscisic acid, the accumulation of water in plant tissues (Radin and Ackerson, 1981;Wittenmayer and Merbach, 2005;Planchet et al, 2011), and mechanisms to protect the PSII enzymatic system based on pigments and antistress enzymes (Munné-Bosch and Lalueza, 2007;Zhang et al, 2011). All these changes tend to reduce photosynthetic efficiency (Munné-Bosch and Lalueza, 2007).…”

Evaluating the Mechanisms of Photosynthetic Inhibition under Growth‐Limiting, Early‐Season Water Deficit Stress in Cotton

“…Not surprisingly, a tremendous amount of research has been aimed at identifying the key limitations to photosynthesis under drought stress in both greenhouse and field-grown cotton (Pettigrew 2004;Ennahli and Earl, 2005;Kitao and Lei, 2007;Zhang et al, 2011;Chastain et al, 2014;Snider et al, 2014). Not surprisingly, a tremendous amount of research has been aimed at identifying the key limitations to photosynthesis under drought stress in both greenhouse and field-grown cotton (Pettigrew 2004;Ennahli and Earl, 2005;Kitao and Lei, 2007;Zhang et al, 2011;Chastain et al, 2014;Snider et al, 2014).…”

“…1986), it is well established that a cotton plant will only retain the number of fruit that it has the total photosynthetic capacity to support. Not surprisingly, a tremendous amount of research has been aimed at identifying the key limitations to photosynthesis under drought stress in both greenhouse and field-grown cotton (Pettigrew 2004;Ennahli and Earl, 2005;Kitao and Lei, 2007;Zhang et al, 2011;Chastain et al, 2014;Snider et al, 2014). Net photosynthetic rates are influenced by rates of photosynthetic processes such as the thylakoid and C fixation reactions, and also by C loss mechanisms including dark respiration and photorespiration .…”