珍稀濒危植物狭叶坡垒的光合特性

选取2007年8月上旬的晴天,用LI-6400便携式光合作用测定仪测定了濒危植物狭叶坡垒的光合特性。结果表明,狭叶坡垒的光饱和点(LSP)约为1 366.67μmol.m-2.s-1,光补偿点(LCP)约为5.62μmol.m-2.s-1。狭叶坡垒的净光合速率(Pn)日变化曲线为"双峰"型,变化趋势与蒸腾速率(Tr)、气孔导度(Gs)等因子相同,与胞间CO2浓度(Ci)相反,Pn的午间降低主要受环境因素的影响。数据分析表明,光照强度(PAR)是狭叶坡垒光合作用和蒸腾作用的主要影响因子。光照不足,水分利用率(WUE)低,是造成其生长缓慢的重要原因。

Photosynthesis characteristics of rare and endangered plant Hopea chinensis

The photosynthetic characteristics of rare and endangered plant Hopea chinensis with the Li-6400 portable photosynthesis system on clear days in the first ten days of August 2007. The results showed that the light saturation and compensation efficiency of H.chinensis were about 1 366.67 and 5.62 μmol·m~(-2)·s~(-1). The curve of diurnal variations of photosynthetic rate(Pn) had two peaks, and changed positively with the variations of transpiration rate(Tr) and stomatal conductance(Gs), but negatively with internal CO_2 concentration(Ci). The mid-depress of Pn was principally caused by environment factors. Correlation analysis among photosynthetic parameters showed that photosynthetically active radiation(PAR) were the primary direct factors affecting Pn, Tr, that light deficiency and low water use efficiency(WUE) was the main reason resulting in the plant grew slowly.