热带雨林三种树苗叶片光合机构对光强的适应

对生长在不同光强(自然日光的8％，25％，50％)下西双版纳热带雨林3种木本植物团花(Anthocephalus chinensis)、玉蕊(Barringtonia pendala)和藤黄(Garrcinia hanburyi)幼苗光合机构的研究表明，随着生长光强的升高，植物叶片的光饱和点、补偿点、净光合速率和非光化学淬灭系数(NPQ)升高，而表现量子效率(AQY)、有效光化学量子产量(Fv／Fm)、光化学淬灭系数(qP)下降．在抗氧化系统中，超氧化物歧化酶(SOD)、抗坏血酸过氧化酶(APX)活性随着光强的升高而升高，而过氢化物酶(CAT)活性与生长光强的变化不一致．抗坏血酸(AsA)含量随着光强的升高而急剧上升。最能反映PFD的变化．可以认为，除与叶黄素循环有关的热耗散增大之外，植物叶片抗氧化系统的加强也是响应强光的一种保护措施．

Acclimation of foliar photosynthetic apparatus of three tropical woody species to growth irradiance

The photosynthetic characteristics and protective role of leaf antioxidant systems were studied for seedlings of three woody species, Anthocephalus chinensis,Barringtonia pendala,Garcinia hanburyi, acclimated to 8%, 25%, 50% of natural sunlight for four months. As growth irradiance increased, the saturation points,the light compensation points of photosynthesis,the maximum net photosynthetic rate,and the non-photochemical quenching efficiency of three species were increased, while the apparent quantum yield (AQY), the effective quantum efficiency (Fv'/Fm'), and the photochemical quenching efficiency (qP) were decreased.In protective enzymes systems, SOD and APX activities increased with increasing growth irradiance, but CAT activity was not consistent with PFD. AsA exhibited the most dramatic increase in response to growth irradiance. It could be concluded that besides the increase in xanthophyll cycle-dependent energy dissipation, the enhancement of leaf antioxidants was also a protective pathway against high light intensity.