沙冬青几种光合特性的季节性变化的研究(英)

Seasonal Changes in Photosynthetic Characteristics of Ammopiptanthus mongolicus

研究了沙冬青（Ammopiptanthusmongolicus（Maxim．）Chegf．）几种光合特性的季节性变化。在气温升高时，沙冬青净光合速率（Pn）、气孔导度（Gs）和气孔限制值（Ls）均呈现下降趋势，而胞间CO2浓度（Ci）却呈上升趋势。根据Farquhar和Sharkey提出的关于区分气孔限制的两个标准，结果表明Pn的下降可能是非气孔限制因素导致。研究还证明，Rubisco大亚基的相对含量以及光化学活性与Pn的季节性变化相关，表明CO2同化的季节性变化主要取决于上述两种因素的变化。

Seasonal changes in the photosynthetic characteristics of Ammopiptantus mongolicus (Maxim. )Chen f. were studied. When the net photosynthetic rate decreased with the elevation of air temperature, thestomatal conductance and stomatal limitation value tended to decline simultaneously, while the interoellularCO2 concentration was increased. According to the two criteria discriminating the stomatal limitation of Photosynthesis suggeSted by Fmrquhar and Sharkey, the seasonal changes in these parameters indicated that the decrease in Pn may not be due to stomatal factor. These studies proved that the relative contents of the large subunit of Rubisco and the photochemical activities correlated with the seasonal changes in the net photosyntheticrate, whieh may show that these two factors contribute primarily to the seasonal changeS in CO2 assimilation.