1-甲基环丙烯对硬溶质型桃果实细胞壁多糖降解特性的影响

Effect of 1-methylcyclopropene on the cell wall polysaccharides degradation characteristics in non-melting-flesh peach fruit

以硬溶质型桃"晚湖景"为试材,20℃下用1μL/L 1-甲基环丙烯(1-MCP)密闭处理24h,研究1-MCP处理对细胞壁降解过程中多糖组分变化、单糖解离特性以及细胞壁多糖降解相关酶的影响。结果表明:1-MCP处理可以明显抑制硬溶质型桃果实硬度的下降,降低乙烯释放量。1-MCP处理的硬溶质型桃果实中CDTA-2、Na2CO3、KOH和CWM-残渣组分在贮藏过程中下降速率都明显低于未处理果。1-MCP处理能延缓CDTA溶性果胶多糖的解离。同时还抑制了Na2CO3溶性果胶多糖中半乳糖醛酸和鼠李糖构成的主链和阿拉伯糖、半乳糖支链的降解,对半纤维素和纤维素多糖成分降解有一定程度的抑制作用。1-MCP处理可能通过抑制参与细胞壁多糖降解相关酶的活性,从而抑制硬溶质型桃果实细胞壁多糖降解及单糖解离,达到延缓果实软化的目的。

Non-melting-flesh peach fruits ＂Wanhujing＂ were used as materials,which were treated with 1μL/L 1 - methylcyclopropene（1-MCP） for 20h at 20℃to study the effect of 1-MCP on the degradation characteristics of cell wall polysaccharides and the effects of cell wall degradation enzymes on peach fruit softening. The results showed that 1-MCP effectively delayed the decline of peach fruit firmness and also delayed the increase of endogenous ethylene production. The rate of decrease in CDTA-2, Na2CO3, KOH,and CWM- residue contents were significantly lower than untreated fruit. 1-MCP treatment could delay the dissociation of CDTA-soluble pectin polysaccharides 1-MCP also inhibited the degradation of galacturonic acid main chain composed of rhamnose and arabinose,galactose branched-chain in Na2CO3 soluble pectin polysaccharides. And it inhibited the degradation of hemicellulose and cellulose polysaccharide. The analysis of the changes of the activities of enzymes ,combining with the character of the degradation of sugars during peach fruits treated by 1-MCP suggested that,by restraining the relative enzyme activities, 1-MCP treatment can restrain the degradation of cell wall polysaccharides,thus delaying peach fruit softening.