Transpiration and Leaf Movement in Field Grown Cottons under Arid Conditions
Chunyan Wang, Akihiro Isoda, Zhiyuan Li and Peiwu Wang


Abstract: Five cotton (Gossypium hirsutum L.) cultivars were grown in field in Xinjiang, China to evaluate their adaptation abilities under arid condition in terms of leaf temperature, flow rate of stem sap and leaf movement. Leaf temperatures were higher in the morning and lower in the afternoon as compared with air temperature. There were large differences in the flow rates of stem sap (FRSS) among the cotton cultivars. The transpiring rates in cotton depended generally on vapor pressure deficit (VPD). In the cultivars with low transpiring ability, however, the influence of VPD was less in the higher range of VPD. Cultivars with higher transpiring ability tended to have larger intercepted radiation per unit leaf area (IRL), i.e., performing active diaheliotropic leaf movement. The higher transpiring ability in cotton might be able to reduce heat stresses caused by diaheliotropic leaf movement and have a possibility to be beneficial for yield under the arid conditions.