阶段降温对冷藏黄瓜耐冷性的诱导作用

Induction of chilling tolerance in cold-stored cucumbers by slowly cooling treatment

黄瓜是冷敏型蔬菜,其果实在冷藏期间容易发生冷害,从而严重影响采后果实的商品性。为了探究阶段降温处理对冷藏黄瓜耐冷性的诱导作用,在采后黄瓜冷藏前,依次于10℃处理24 h、5℃处理48 h。结果表明,阶段降温处理显著降低了冷藏黄瓜的冷害指数、相对电导率、次生病害病情指数,显著提高了PSⅡ原初光能转化效率(Fv/Fm),表明阶段降温处理有效诱导了冷藏黄瓜的耐冷性,从而减轻了冷藏黄瓜的冷害程度。阶段降温处理明显增加了冷藏黄瓜的总可溶性固形物含量和总可溶性蛋白质含量,降低了冷藏黄瓜的丙二醛含量、过氧化氢含量及超氧阴离子自由基产生速率,显著增强了冷藏黄瓜的超氧化物歧化酶活性、过氧化氢酶活性和过氧化物酶活性,提高了相关酶基因的表达量。由研究结果可知,阶段降温处理诱导的黄瓜耐冷性与渗透调节物质的积累及黄瓜抗氧化系统被激活有关。

Cucumber is a kind of cold-sensitive vegetable,the fruits are easy to occur chilling injury during cold storage periods,and the commercial quality of postharvest fruits can be seriously affected.To explore the induction of slowly cooling treatment on chilling tolerance of cold-stored cucumbers,postharvest cucumbers were treated at 10℃for 24 h and 5℃for 48 h successively before cold storage.The results showed that slowly cooling treatment significantly reduced the chilling injury index,relative conductivity,secondary disease index of cold-stored cucumbers,and significantly increased the efficiency of primary light energy of PSⅡ(Fv/Fm),suggesting that slowly cooling treatment effectively induced chilling tolerance of cold-stored cucumbers,thus relieved the degree of chilling injury in cucumbers.Slowly cooling treatment obviously increased the contents of total soluble solids and total soluble proteins,reduced the contents of H2O2 and malondialdehyde(MDA),and O2·-production rate in cold-stored cucumbers,while activities of superoxide dismutase,catalase and peroxidase and relative enzyme gene expression were significantly enhanced.It can be seen from the results that chilling tolerance of cucumbers induced by slowly cooling treatment is related to the accumulation of osmotic adjustment substances and the activation of antioxidant system in cucumbers.