Response of Chlorosis and Growth to Light Intensity in Rice Seedlings

Chlorosis is a crucial factor affecting the normal growth of rice seedlings. Light intensity can significantly control chlorosis, but uncertainty about the key factors of chlorosis caused by light intensity still exists. The purpose of this work is to determine what causes the light intensity to affect chlorosis. Xiangzaoxian 24 was used as the test material to investigate the effects of light intensity on rice seedlings by setting five light intensity treatments, T1 (50 μmol m^–2 s^–1), T2 (100 μmol m^–2 s^–1), T3 (250 μmol m^–2 s^–1), T4 (500 μmol m^–2 s^–1), and T5 (750 μmol m^–2 s^–1). In this study, chlorophyll content, ascorbic acid (AsA) content, and related gene expression levels decreased, but the H₂O₂ content increased under lower or higher light intensity. Moreover, there was obvious chlorosis in rice seedlings in it. But there was no obvious chlorosis in rice seedlings at medium light intensity. We concluded that medium light intensity could promote AsA synthesis and thus reduce reactive oxygen species, and ultimately the rice seedlings stay green.