[Effect of Modified Chitosan Loaded with Silica on Arsenic Uptake and Transport in Rice]

Chitosan loaded with silica foliar spraying material (NCSI) was prepared using natural biomass chitosan and organic silicon and was applied to Lindao 16, Nanjing 2728, Zhenghan 10, and Nongken 58 at the rice filling stage to study the effects on arsenic (As) absorption in rice. The results showed that under a 100 μmol·L^-1 pentavalent arsenic[As(Ⅴ)] hydroponic environment, foliar spraying of 30 mL NCSI on leaves promoted the accumulation of As in leaves and reduced the accumulation of As in roots and grains. Among them, the As contents of Nanjing 2728, Zhenghan 10, and Nongken 58 grains were decreased by 14.44%, 21.66%, and 10.85%, respectively, compared with those of the blank group on the 3^rd day after spraying NCSI. Meanwhile, foliar spraying of NCSI improved the activities of CAT and SOD in rice leaves and increased the GSH content, indicating that the spraying of NCSI alleviated the stress of As on rice, improved the tolerance of rice to As, and reduced the toxicity of As to rice. The main mechanism of foliar application of NCSI to reduce As accumulation in rice grains may have been that NCSI induced GSH production in leaves, reducing more As(Ⅴ) to trivalent arsenic[As(Ⅲ)], thereby promoting As chelating in leaves and inhibiting As migration to grains. Therefore, foliar spraying of NCSI can be used as a foliar control technology to solve the problem of excessive As in rice and provide a scientific basis for the safe production of rice in China.