Adaptive Responses of Soybean and Cotton to Water Stress: I. Transpiration Changes in Relation to Stomatal Area and Stomatal Conductance

Effects of Water Stress on Leaf Temperature and Chlorophyll Fluorescence Parameters in Cotton and Peanut

“…Several reports have showed that water stress decreased the stomatal aperture, stomatal conductance and transpiration rate (Shimshi, 1963;Li et al, 2004;Inamullah and Isoda, 2005a). In this experiment, the water stress decreased the transpiration rate in both crops (Fig.…”

“…Cochard et al (2002) reported that stomatal conductance is the main mechanism of regulating transpiration. It was also suggested that the water extracting ability of roots would concern stomatal conductance resulting in transpiring ability (Inamullah and Isoda, 2005a). The relationship between transpiring ability (transpiration per unit leaf area) and RDW was not obvious in peanut as compared with cotton (Table 3).…”

Adaptive Responses of Soybean and Cotton to Water Stress II. Changes in CO2Assimilation Rate, Chlorophyll Fluorescence and Photochemical Reflectance Index in Relation to Leaf Temperature

“…The lower A N in soybean in higher water-stress treatments and at noon could be related to the direct photodamaging effect of water scarcity and/or to the photodamaging effect of the higher leaf temperature (T L ), caused by water-stress as reported by Ludlow and Björkman (1984). In cotton, the decrease in A N was smaller probably because of its higher soilmoisture absorption capability as we reported earlier (Inamullah and Isoda, 2005) and the smaller increase in T L . The decrease in A N in cotton under water stress was mostly due to the reduced stomatal opening (Inamullah and Isoda, 2005).…”

“…Previously, we reported that the decrease in CO 2 assimilation rate and increase in leaf temperature in water-stress condition were larger in soybean than in cotton (Inamullah and Isoda, 2005). The decrease in CO 2 assimilation rate was attributed to photoinhibitory damage caused by water stress and higher leaf temperature as reported by Ludlow and Björkman (1984) and/or to the down-regulation of photosystem (PS) II and dissipation of excess excitation energy as heat (Krause, 1988;Bilger et al, 1995;Lu et al, 2001;Alves et al, 2002).…”

“…In soybean (Glycine max (L.) Merr. ), paraheliotropic leaf movement may help the crop to avoid photoinhibition (Hirata et al, 1983), while in cotton (Gossypium hirsutum L.) diaheliotropic leaf movement (Ehleringer and Forseth, 1989;Wise et al, 2000), may increase transpiration to keep its leaf temperature low (Isoda and Wang, 2002;Inamullah and Isoda, 2005). Photoinhibition is typically characterized by a reduction in quantum yield of PSII (Fv/Fm) (Demmig and Björkman, 1987).…”