摘要
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 。
The changes of fruit firmness,polygalacturonase (PG) activities and the ultrastructure of the cell wall during postharvest ripening of 2 kiwifruit [Actinidia deliciosa (A.Chev) C.F.Liang et A.R.Fergusm] clones were studied.The results show that the fruit firmness decreases rapidly after being picked with 2 obvious decrease periods.The firmness decreases faster in the first period than in the second period.The PG activities increase slowly in the early storage period,but in the later storage period,the activities increase quickly with the gradual dissolving and disappearing of the middle colloidal layer of cell wall.The fibre of cell wall relaxes,and the cell plasm begins to dispers,but the plasma membrane and the cell organelle keep in good conditions when the fruit begins to get soft.Among different varieties,the clone of better storeability has the characteristics of slower increase of PG activities,slower decrease of fruit firmness,better cell wall and middle colloidial layer structure,and slower dissolving of middle collodial layer.The softening of hard fruit in the late storage period has close relation with the increase of PG activities and the dissolving of cell wall caused by the hydrolyzation of pectic substance,while the time of fruit storage is determined by the procedure of cell's senility and dissolving caused by the damage to cell plasm by oxidation.
出处
《湖南农业大学学报（自然科学版）》
CAS
CSCD
2000年第6期457-460,共4页
Journal of Hunan Agricultural University(Natural Sciences)
基金
湖南省自然科学基金资助项目! (94- 2 6 )
