增强UV-B辐射下NO对细胞壁多糖组分含量的影响

以豌豆（Pisum sativum）幼苗茎为材料,研究增强UV-B辐射下一氧化氮（NO）对细胞壁多糖组分含量的影响。结果表明,增强UV-B辐射使单位长度内细胞壁多糖总量增加;使细胞壁多糖结构组分果胶、半纤维素Ⅰ、半纤维素Ⅱ和纤维素的含量增加;NO供体处理对半纤维素Ⅰ、半纤维素Ⅱ和纤维素的影响与UV-B辐射相似,使它们含量增加;增强UV-B辐射条件下,氮合酶（NOS）抑制剂和NO清除剂处理使半纤维素Ⅰ、半纤维素Ⅱ和纤维素的含量降低,抵消了增强UV-B辐射对他们的影响。说明UV-B辐射可能通过NO信号上调了半纤维素Ⅰ、半纤维素Ⅱ和纤维素含量,增加了他们在细胞壁多糖中的比例,因而改变细胞壁的化学特性以及影响了细胞壁的机械延展性。无论对照条件下用NO供体处理,还是UV-B辐射条件下用NOS抑制剂、NO清除剂处理,对果胶含量影响不大,表明NO信号可能与UV-B辐射诱导果胶含量增加无关。

Effects of NO on Contents of Cell Wall Polysaccharides Fraction under Enhanced UV-B Radiation

Effects of nitric oxide(NO) on contents of cell wall polysaccharides fraction in stems of pea(Pisum sativum)seedlings under enhanced UV-B radiation were studied.Results showed that total contents of cell wall polysaccharides,and contents of pectin,hemicellulose I,hemicellulose II and celluloses at pea seedling stems per unit length increased under UV-B radiation.NO donor treatment also increased contents of hemicellulose I,hemicellulose II and celluloses at pea seedling stems per unit length.Under UV-B radiation treatments,the additional inhibitor of nitric oxide synthase and NO scavenger abated the effects of UV-B radiation on contents of hemicellulose I,hemicellulose II and celluloses,making their contents decreased.It is believed that UV-B radiation,with NO as a probable signaling molecule,can increase the contents of hemicellulose I,hemicellulose II and celluloses.So their proportions among cell wall polysaccharides increase too.These changes might regulate the chemical properties and mechanical ductility of cell wall.Whether NO donor treatment under control condition,or NOS inhibitor and NO scavenger treatments under UV-B radiation had no effects on contents of pectin,which suggest that the effect of NO signaling on increase of pectin contents induced by UV-B radiation can be excluded.