Leaf diaheliotropic movement can improve carbon ga

Authors: Y L Zhang H Z Zhang G Y Feng J S Tian W F Zhang

Publish Date: 2010/02/17

Volume: 47, Issue: 4, Pages: 609-615

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Abstract

Upland cotton Gossypium hirsutum L can move leaves to track the sun throughout the day socalled leaf diaheliotropic movement This paper reports an experimental test of the hypothesis that leaf diaheliotropic movement in upland cotton can enhance carbon assimilation and not increase the risk of stress from high energy load In this experiment cotton leaves were divided into two groups one was that leaves could track the sun freely another was that leaves were retained to the horizontal position The diaheliotropic leaves recorded higher incident irradiance than the restrained ones especially in the morning and late afternoon Compared with restrained leaves diaheliotropic leaves were generally warmer throughout the day As expected diaheliotropic leaves had significantly higher diurnal time courses of net photosynthetic rate P N than restrained leaves except during 1400–1800 of the local time Higher instantaneous wateruse efficiency WUE was observed in diaheliotropic leaves in the early morning and late afternoon than in the restrained leaves During the given day diaheliotropic and restrained leaves had similar diurnal time courses of recovery of maximal quantum yield of PSII photochemistry Fv/Fm Diaheliotropic leaves recorded lower or similar photochemical quenching coefficient qp than restrained leaves did throughout the day These results suggest that cotton leaf diaheliotropic movement can improve carbon gain and water use efficiency and not intensify photoinhibition

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