Photosynthetic gas exchange and chlorophyll fluorescence parameters in response to illumination intensity in leaves of Lespedeza davurica under different light environments

In order to understand the adaptability of Lespedeza davurica on different forest light environmental, photosynthetic gas exchange and light response curve of chlorophyll fluorescence parameters were detected respectively. The results showed that Pn and AQY of L. davurica leaf growth in understory were significantly higher than that of the forest edge under low light intensity, which indicated that the ability of capture and utilization of weak light growth in understory were significantly higher than that in the edge of forest. On the contrary, the ability of capture and utilization of strong light growth in understory was significantly lower than that in the edge of forest, in which the value of LSP and Pmax were lower. The increased extent of GS and Tr of L. davurica leaves understory were lower than the edge of the forest with increasing the light intensity, but L. davurica grown in forest has relatively higher water use efficiency. Under low light intensity, the parameters of ФPSⅡ and ETR were both not different between understory and forest edge. But the parameters of ФPSⅡ and ETR for those grown in forest edge were higher than understory when the intensity was more than 400 μmol·m-2·s-1, ETR and LCP of L. davurica leaves were significantly higher than those understory. The heat dissipation capability of understory was higher than those grown in forest edge. In conclusion, the results of this study showed that the ability of L. davurica for adapting different light environments were strong.