不同光强下红锥幼苗叶绿素荧光参数的日变化

测定分布在不同光照强度（全光照、遮荫下光强分别相当于自然光照的80％、30％和20％）的红锥（Castanopsis hystrix）盆栽幼苗叶绿素荧光参数的日变化过程,以探讨红锥幼苗生长对光强的适应性.结果显示,4种生境光强下的叶绿素荧光参数日变化趋势基本一致;低光强下（30％和20％光强）的有效光化学量子产量（Fv＇/Fm＇）、光化学淬灭系数（qP）和最大光能转化效率（Fv/Fm）显著高于高光强下（全光照和80％光强）的对应值,且三者均表现为中午较低,傍晚最高的趋势;相对表观电子传递速率（ETR）和非光化学淬灭系数（NPQ）表现为随生境光强的增加而升高的趋势,低光强下显著低于高光强下的对应值,且两者均表现为傍晚最低.研究表明,红锥盆栽幼苗对低光强的适应性很强,适当遮光有利于提高红锥苗的光合能力.

Diurnal Changes of Chlorophyll Fluorescence Parameters of Castanopsis hystrix Seedlings under Different Light Intensities

Diurnal changes of chlorophyll fluorescence parameters of Castanopsis hystrix seedlings were measured under different light intensities （full-exposure, shaded to 80%, 30% and 20% ambient light）, in order to discuss the adaptability of Castanopsis hystrix seedlings to light intensity. The results showed that the diurnal changes of Chlorophyll fluorescence parameters under four different environment light intensities were similar. Fv＇ /Fm＇ , qP and Fv/Fm under low light intensities （30% , 20% am- bient light） were significantly higher than those under high light intensities （full-exposure, 80% ambient light）, and the three indicators showed lower at noon and the highest at evening. Both ETR and NPQ in- creased with the increase of environment light intensity, which under low light intensities were signifi cantly lower than those under high light intensities and were the lowest at evening. Results suggested that the adaptability of Castanopsis hystrix seedlings to low light intensities was strong and moderate would be beneficial for improving the photosynthetic capacity of Castanopsis hystrix seedlings shading