桃冷害细胞学表现与品质劣变关系的研究

Studies on the Relationship between Cell Deformation and Quality Deterioration of Peach by Chilling Injury

用电子显微镜观察新鲜桃果实及不同条件下贮藏后的果实发现,成熟桃果肉组织的共同特征是:细胞明显液泡化,液泡占细胞体积的90％以上。细胞壁、细胞核、叶绿体、线粒体等亚细胞结构完整。常温(28℃)条件下自然衰老及高二氧化碳环境中贮藏的桃,末观察到细胞壁加厚、胞间连丝增加及内含物穿壁流动现象。不同品种果实在0℃恒温下冷藏细胞学表现不同,绿化9号和北京13号桃,贮后口感质地细嫩、风味浓郁,在一定期限内未观察到细胞壁加厚、胞间连丝增多增粗。大久保桃贮后表现质地生硬、木渣化,风味丧失等严重冷害症状,其细胞超微结构表现为:胞间连丝增多、加粗,细胞之间相互贯通,细胞内含物在其中流动;细胞壁局部缢缩或不均匀加厚,细胞变形。由此认为,细胞间通道剧增,细胞内含物大量外泄,细胞壁次生增厚是低温引起的细胞伤害,是冷害造成果实品质劣变的直接原因。

The ultrastructure of peach mesocarp cell was observed by a transmission electron mi-croscope before or after cold storage.A common characteristic of mature fresh peach was that the mesocarp cell largely vacuolated with cytoplasm confined to a narrow layer adjacent to the cell wall. The cellular contents, cell membranes and cell wall remained intact. Cell wall thickening and plasmodesmus strengthening were not observed in the peach of normal sene-scence at 28℃and stored in the high CO2 (above 12%) environment. Beijing 13 and Luhua 9 peach was tender and juicy after cold storage, and thickened walls and strengthened plasmodesmus were not observed; but thickened walls and deformed cells in Dajiubao peach were very evident; the plasmodesmus strengthened, the cellular contents exchanged between cells, the ability to ripen lost, the flesh woodliness was serious, and the taste was insipid. Therefore, cell deformation caused by low temperature was the direct reason that chill injury resulted in peach quality deterioration.