药用植物金荞麦的光合特性研究

Studies on photosynthetic characteristics of medicinal plant Fagopyrum cymosum

目的:研究金荞麦叶片的光合特性,为提高金荞麦的产量和质量提供依据。方法:自然条件下利用LI-6400型便携式光合系统测定金荞麦品种贵州Ⅰ号和江苏Ⅱ号孕蕾期叶片的光响应及光合日变化进程。结果:金荞麦叶片的光响应曲线符合非直角双曲线方程,贵州Ⅰ号金荞麦的光饱和点和光补偿点均高于江苏Ⅱ号金荞麦,对环境的适应能力较强。金荞麦叶片的净光合速率、光合有效辐射、蒸腾速率和气孔导度的日变化曲线均呈单峰曲线,不存在明显的"午休"现象。相关性分析表明,金荞麦叶片净光合速率与气孔导度、光合有效辐射、蒸腾速率和水分利用效率等呈正相关,与胞间CO2浓度呈负相关。结论:金荞麦为阳生植物,气孔导度、光合有效辐射和蒸腾速率是影响金荞麦叶片净光合速率的主要环境因子。

Objective ： To study the photosynthetic characteristics of leaves for improving the quantity and quality of Fagopyrum cymosum. Method ： The light-response and diurnal photosynthesis course of leaves at the booting stages of F. cymosum species Guizhou Ⅰ and Jiangsu Ⅱ , were analyzed by LI-6400 system under natural condition. Result： The light-response curve of F. cymosum matched the non-rectangular hyperbola model, and the light saturation point （LSP） and light compensation point （LCP） of Guizhou Ⅰ were higher than those of Jiangsu Ⅱ , which implied that F. cymosum of Guizhou Ⅰ could adapt to environment more widely. Diurnal course curves of the net photosynthetic rate, photosynthetically active radiation, stomatal conductance and transpiration rate all had a single peak, without obvious ＂midday depression＂. The relativity analysis indicated that the net photosynthetic rate of F. cymosum had a positive correlation to the stomatal conductance, photosynthetically active radiation, transpiration rate and water utilization efficiency, and negative to the intercellular CO2 concentration. Conclusion： Stomatal conductance, photosynthetically active radiation and transpiration rate were the main environment factors that affected the net photosynthetic rate of F. cymosum.