施硅提高水稻叶片对紫外线胁迫的抗性

采用加硅与缺硅营养液培养的方法,首次研究证明硅能提高水稻(Oryza sativa L.)叶片抗紫外线胁迫的能力.结果表明,在紫外胁迫条件下,缺硅水稻叶片表面出现明显的棕色伤害斑点,而加硅叶片未出现伤害症状.硅在水稻表皮细胞壁及细胞内部的积累明显促进了紫外吸收物质在表皮细胞中的聚集,使表皮中可溶性酚类物质含量提高17%,不溶性紫外吸收物质的含量增加65%左右.荧光显微镜观察表明,在表皮细胞外壁或胞内沉积的水合二氧化硅固体中包含着大量不溶性的酚类化合物,它们与可溶性酚类物质一起在叶片的上、下表皮细胞中形成了吸收紫外线的屏障.

Effects of Silicon on Rice Leaves Resistance to Ultraviolet-B

In order to investigate the possible role of silicon in rice (Oryza sativa L.) leaves resistance to ultraviolet-B (UV-B), experiments were conducted by using rice plants solution-cultured with or without silicon supplementation. Results showed that under high UV-B irradiation the silicon-deficient leaves exhibited obvious brown spots and strips of UV damage symptoms, but the silicon-treated leaves were not affected. A 21% and 67% increase in soluble and insoluble UV-absorbing compounds was observed in the epidermis of silicon-treated leaves, respectively. Furthermore, fluorescence microscopy revealed that a great deal of insoluble UV-absorbing compounds was enriched in silicon bodies that were formed in the cell walls and cell lumina of epidermis of silicon-treated leaves, whereas the insoluble UV-absorbing compounds were less in the epidermis of non-silicon-treated leaves. Based on these results, it is concluded that the elevated UV resistance of silicon-treated leaves is due to the increase of phenolic compounds in epidermis induced by silicon.