濒危植物翅果油树的光合生理特性研究

Photosynthetic Characteristics of Endemic and Endangered Plant Elaeagnus mollis

采用Li-6400便携式光合仪对自然生长的翅果油树的光合特性进行研究，结果表明：（1）翅果油树叶片的净光合速率（Pn）日变化呈双峰曲线，高峰值出现在11：00和15：00，存在明显的光合“午休”现象．（2）翅果油树的光补偿点（LCP）为46．1085μmol·m^-2·s^-1，光饱和点（LSP）在1400μmol·m^-2·s^-1左右，光补偿点和光饱和点都比较高，表明其是典型的阳生植物，对光适应的生态幅度较窄，这可能是其濒危的原因之一；表观量子效率日变化范围在0．0355μmol·mol^-1 -0．0534μmol·mol^-1之间．（3）翅果油树的CO2补偿点为83．1914μmol·m^-1，CO2饱和点在700μmol·mol^-1左右，预测环境CO2浓度的升高对翅果油树光合作用的促进作用会很小；羧化效率日变化与净光合速率（Pn）日变化趋势基本一致，变化范围为-0．0040μmol·m^-2·s^-1 -0．0298μmol·m^-2·s^-1．

Using Li-6400 portable photosynthesis system, the photosynthetic characteristics of Elaeagnus moUis under natural conditions were studied. The main results were as follows ： （ 1 ） The diurnal changes of net photosynthetic rate （Pn） in E. mollis display a dual-peaked pattern, the peak value appeared at 11：00 and 15：00, and had a ＂midday depression＂. （2） The light compensate point （LCP） of leaves was 46. 108 5μmol·m^-2·s^-1, and the light saturate point （LSP） was about 1 400μmol·m^-2·s^-1. Both LCP and LSP were very. high, which indicated that E. mollis was a sun plants, and its ecological ranges of light adaptability were narrow, this may be one of the factors resulting in E. mollis in danger of extinction ; Apparent quantum yield were between 0. 035 5 μmol·mol^-1 - 0.053 4μmol·mol^-1 （3） The CO2 compensate point was 83. 191 4 μmol·mol^-1, the CO2 saturate point was about 700 μmol·mol^-1, so we predicted that the increasing CO2 concentration of environment will do little promotion to photosynthesis of E. moUis; the carboxylation efficiency were between - 0. 004 0 μmol·m^-2·s^-1 - 0. 029 8μmol·m^-2·s^-1, which diurnal changes tendency were almost the same as the pn.