Effects of Light Intensity on Morphological Structure and Physiological Characteristics of Gleditsia sinensis Seedlings.

The purpose of this paper is to explore the effects of different light intensities (50, 100, 200 μmol/m2 s) on the morphogenesis, physiological characteristics and dry matter accumulation of Gleditsia sinensis Lam. seedlings, and to find out the suitable light intensity for the growth of Gleditsia sinensis seedlings. In this study, it was found that with the increase of light intensity, the seedling index, biomass accumulation, photosynthetic pigment content and leaf thickness of Gleditsia sinensis seedlings increased significantly. L1 (50 μmol/m2 s) treatment was not conducive to the growth of Gleditsia sinensis seedlings. The chloroplast structure of the leaves under this treatment was damaged, and the chlorophyll content was low. The starch content, soluble sugar content, soluble protein content, POD activity and SOD activity of Gleditsia sinensis seedlings under L1 treatment were significantly lower than those under L3 (200 μmol/m2 s) treatment. L2 (100 μmol/m2 s) treatment resulted in significantly higher cell tense ratio(CTR)than L1 and L3 treatments, and stomatal length and width were significantly lower than those of L1 and L3 treatments. L3 (200 μmol/m2 s) treatment was beneficial to the stem thickening growth and the accumulation of dry matter, chlorophyll, carotenoid and soluble sugar content of Gleditsia sinensis seedlings, and the accumulation of malondialdehyde (MDA) was significantly reduced. There was no significant difference in Fv/Fm, α and Ik of Gleditsia sinensis seedling under different light intensities, but the F0, Fm and ETRmax of Gleditsia sinensis seedling under L3 treatment were significantly higher than those under L1 treatment.The results show that the light intensity of 200 μmol/m2 s is more suitable for the growth of Gleditsia sinensis seedlings than the other two treatments. The light intensity below 50 μmol/m2 s is not conducive to the growth of Gleditsia sinensis seedlings, and to some extent, it will damage the structure of photosynthetic organs of Gleditsia sinensis. [ABSTRACT FROM AUTHOR]