低夜温后不同光强对榕树叶片PSⅡ功能和光能分配的影响

研究了自然低夜温后全光照与遮荫对榕树叶片PSⅡ功能及光能分配的影响。结果表明低夜温后全光照条件下叶片吸收光能分配于光化学反应部分减少，而热耗散部分和反应中心过剩光能则增加，从而导致了PSⅡ功能的下降，遮荫条件下光能分配于光化学反应的程度增加．虽然用于热耗散的比例下降了，但反应中心过剩光能相对较少，从而有利于PSⅡ功能的恢复。

Effects of different light intensity after low night temperature stress on PSII functions and absorbed light allocation in leaves of Ficus microcarpa

In this study, the effects of full sunlight and shade after natural low night temperature on PSII functions and light allocation in leaves of Ficus microcarpa was examined. Under full sunlight after low night temperature, the allocation of light absorbed by PSII antennae to the photochemical reaction decreased, but the allocation of absorbed light to thermal dissipation and excessive energy increased. So it resulted the decrease of the PSII functions. Though the allocation of absorbed light to thermal dissipation decreased, shade after low night temperature can decrease excessive energy of PSII reaction centers by increase of fraction of light absorbed in PSII antennae that was utilized in PSII photochemistry, and protect the photosynthetic apparatus not to be injured. So shade after low night temperature was beneficial to recover PSII functions.