喀斯特石漠化地区三种豆科牧草光合与蒸腾特性的研究

Study on the Photosynthetic Rate and Water Use Efficiency of Three Leguminous Grass Species in Karst Rocky Desertification Area

在晴天条件下研究了喀斯特石漠化地区白三叶、红三叶、紫花苜蓿的净光合速率、蒸腾速率、水分利用效率等光合生理生态特性,结果表明:白三叶、红三叶和紫花苜蓿的日均净光合速率分别为10.01μmolCO2/m2·s、8.48μmolCO2/m2·s、8.07μmolCO2/m2·s,白三叶日均净光合速率高于后两者,同时白三叶日均蒸腾速率又低于红三叶和紫花苜蓿。相对而言,白三叶属于高光合、低蒸腾型,红三叶净光合速率和蒸腾速率中等,紫花苜蓿则属于低光合、高蒸腾型,白三叶水分利用效率高于红三叶和紫花苜蓿。从净光合速率、蒸腾速率及水分利用效率等角度综合考虑,白三叶与红三叶、紫花苜蓿相比更适合喀斯特石漠化地区特殊生境条件。

The ecophysiological characteristics of Trifolium repens , Trifolium pratense and Medica- go sativa in Karst rocky desertification area, including the net photosynthetic rate, transpiration rate and water use efficiency, were studied in sunny days. The results showed that： the daily average net photosyn- thetic rates of Trifoliurn repens , Trifolium pratense and Medicago sativa were 10. 01μmolCO2 m-2 s-1 , 8.48μmolCO2 m-2 s-1 , 8.07μmolCO2 m-2 s-1 respectively. At the same time, the transpiration rate of Tri f olium repens was smaller than that of Tri folium pratense and Medicago sativa . Comparatively, Trifolium repens was the species of high photosynthetic and low transpiration, and Trifolium pratense belonged to the type of medium net photosynthetic and transpiration rate, and Medicago sativa was the type of low photosynthetic and high transpiration. Water use efficiency of Trifolium repens was higher than that of Trifolium pratense and Medicago sativa. Therefore, it＇s inferred that Trifolium repens is more suitable for the special habitat conditions in Karst rocky desertification area based on the net photo- synthetic rate, transpiration rate and water use efficiency.