Effects of Shading on Photosynthetic Pigments and Photosynthetic Parameters of Lespedeza Buergeri Seedlings

The changes of photosynthetic pigments and photosynthesis of Lespedeza buergeri seedlings were observed under natural light and after 90 days of shading (45% natural light). Compared with natural light, shading significantly increased the contents of chlorophyll a, chlorophyll b, chlorophyll a + b, chlorophyll a/b ( p < 0.05), and the increase multiples were 1.67, 0.88, 1.46, 0.42, respectively. However, the content of carotenoids decreased under shading, but the decrease was not obvious ( p > 0.05). Shading significantly reduced net photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO 2 concentration and carboxylation efficiency ( p < 0.05), and the reduction multiples were 4.56, 4.17, 4.64, 1.07 and 1.68, respectively. However, the water use efficiency increased under shading, but the improvement was not obvious ( p > 0.05). The results indicated that shading significantly inhibited photosynthesis of L. buergeri seedlings.