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为了深入探索猕猴桃的果实软化衰老机制及其控制途径 ,以耐贮性具有明显差异的美味猕猴桃品系果实为试材 ,对采后果实硬度、多聚半乳糖醛酸酶 (PG)活性及细胞壁超微结构变化进行了研究 .结果表明 ,果实采后硬度明显下降 ,并可分为两个显著下降时期 ,前期硬度下降快于后期 ;采后初期 ,PG活性上升较慢 ,后期则迅速增加 ,随之细胞壁中胶层逐渐降解消失 ,继而细胞壁纤维松散 ,细胞壁膨大 ,但质膜与细胞器仍完好 ,此期果实开始软熟 .不同品系中 ,耐贮性强的品系果实采后硬度下降缓慢 ,PG活性低 ,细胞壁与中胶层结构致密而均匀 ,中胶层降解慢 .硬果的后熟软化与 PG活性增加、果胶质水解引起的细胞壁结构破坏密切相关 ,而软果贮藏则可能取决于细胞膜的氧化伤害而引起的细胞衰老崩解进程
In order to further explore the mechanism of fruit softening and aging of kiwifruit and its control ways, taking the fruits of the kiwifruit variety with significant difference in storage resistance as the test material, the effect of postharvest fruit firmness, polygalacturonase (PG) The results showed that the postharvest firmness of fruit decreased obviously, and it could be divided into two periods of significant decrease, the early stage hardness decreased faster than the latter stage; PG activity increased slowly at the early post-harvest stage, The cell wall in the gradual degradation of the adhesive layer disappeared, and then the cell wall loose fibers, cell wall dilated, but the plasma membrane and organelles are still intact, the fruit began to soft-ripened strains of different strains, storability of the fruit postharvest firmness decreased slowly, PG The activity of cell wall and middle glue layer is dense and uniform, and the degradation of middle glue layer is slow.The postharvest softening of hard fruit is closely related to the increase of PG activity and the disruption of cell wall structure caused by pectin hydrolysis, while the soft fruit storage may depend on Cell membrane oxidative damage caused by the cell senescence disintegration process