采后冷敏果蔬低温逆境下电解质外渗率测定的影响因素

Influencing factors of electrolyte leakage rate determination in cold-sensitive fruits and vegetables under post-harvest chilling stress

冷敏果蔬在不良贮藏环境中遭受损伤,最先影响细胞膜结构与功能,破坏其选择透过性,损伤严重程度影响果蔬货架期间表观品质劣变速度,从而影响其商品价值。果蔬遭受逆境损伤程度与细胞膜透性紧密相关,而细胞膜透性的大小,通常以电解质外渗率进行表征。本研究就渗透提取剂及浓度、振荡时间、组织圆片厚度、不同组织部位等测定影响因素,采用典型冷敏果蔬“申青”黄瓜、“绿丰”西葫芦以及“甜杂”青圆椒作为研究对象选取展开试验,得出0.2 mol·L^(–1)甘露醇溶液为果蔬组织圆片(黄瓜、西葫芦、青圆椒)等渗浓度提取剂,在电解质外渗率测定时选取振荡时间范围90~240 min,组织圆片厚度0.7~2 mm的中果皮作为合适的取样组织进行测定。该研究结果可以更好反映采后果蔬低温逆境下受冷害后细胞膜透性改变的规律。

Cold-sensitive fruits and vegetables are susceptible to damage in unfavorable storage environments,which first affects the cell membrane structure and function,destroying its selective permeability,and the severity of the damage affects the rate of apparent quality deterioration during the shelf life of fruits and vegetables,thereby affecting their commercial values.The degree of stress-induced damage to fruits and vegetables is closely related to the permeability of the cell membrane,which is usually characterized by the electrolyte leakage.This study focused on the factors that affect the determination of permeability extraction agents,including concentration,oscillation time,tissue slice thickness,and different tissue locations.Typical cold-sensitive fruits and vegetables,such as“Shenqing”cucumber,“Lvfeng”zucchini,and“Tianza”green pepper,were selected as research objects for the experiments.The results showed that a mannitol solution of 0.2 mol·L^(-1)was an appropriate concentration of extraction agent for fruit and vegetable tissue slices(cucumber,zucchini and green pepper).The oscillation time range of 90-240 min was chosen for the measurement of electrolyte leakage.Tissue slices with a thickness of 0.7-2 mm from the middle fruit peel were selected as suitable samples for measurement.The findings of this study can better reflect the changes in cell membrane permeability of postharvest fruits and vegetables under low temperature stress.