土壤干旱胁迫对黄栌叶片光合性能的影响

Effect of soil drought stress on photosynthetic characteristics of Cotinus coggygria var.cinerea leaves

为探索土壤干旱胁迫和光照强度对黄栌光合作用性能的影响规律，应用CIRAS-2型便携式光合作用系统，测定4种土壤水分（对照、轻度、中度和重度胁迫）处理下，3年生黄栌（Cotinuscoggygria var．cinerea）苗木叶片光合作用的光响应过程。结果表明：1）土壤干旱胁迫对黄栌叶片的光合性能参数具有明显影响，随着土壤水分胁迫的加剧，黄栌叶片的光合速率、蒸腾速率、光量子效率明显降低，光补偿点增高，叶片水分利用效率在轻度水分胁迫（土壤相对含水量60-65％）下的水平最高；2）黄栌叶片光合作用对强光胁迫的适应性较强，在较大幅度的强光（有效辐射强度1000-1800μmol·m^-1·s^-1）范围内，均能获得较高的光合速率和水分利用效率；3）黄栌光舍作用对弱光的光能吸收、转换和利用效率（光合量子效率）较低，并随土壤水分胁迫加剧而明显下降。

In order to explore the influences of soil water stress and light intensity on photosynthetic characters of Cotinus coggygria var. cinerea,this paper measured photosynthetic response process of Cotinus coggygria var. cinerea under four different conditions of soil moisture with CIRAS-2,a portable photosynthetic system made in PPS corporation of England. The results first indicated that soil water stresses influences the photosynthetic parameters of Cotinus coggygria var. cinerea clearly. With the water stress goes serious, the net photosynthetic rate, transpiration rate and apparent yield all apparently decline, the light compensation points increases. The level of water use efficiency is highest at light water stress when the soil relative water content is about 60-65%. Second, Cotinus coggygria var. cinerea can obtain both high net photosynthetic rate and water use efficiency at a large range of high light whose efficient radiant intensity is about 1000-1800μmol·m^-1·s^-1. Third, the photosynthesis of Cotinus coggygria var. cinerea has low efficiency to the absorbability,conversion and use of low light, and declines clearly as the soil water stress pricks up.