乙烯信号参与水杨酸提高采后李果实抗冷性的研究

为了研究水杨酸(salicylic acid,SA)对采后李果实抗冷能力的影响及其与乙烯信号的关系。本试验以采后中熟期"布朗"李果实为材料,分别对其进行1.0 mmol/L SA、1.0 μL/L 1-甲基环丙烯(1-methylcyclopropene,1-MCP)和1.0 mmol/L SA结合1.0 μL/L 1-MCP处理,以蒸馏水处理作为对照,分析以上处理对李果实在4℃贮藏条件下冷害发生率、冷害指数、过氧化物酶(peroxidase,POD)、多酚氧化酶(polyphenol oxidase,PPO)、细胞膜渗透率、丙二醛(malondialdehyde,MDA)含量、超氧化物歧化酶(superoxide dismutase,SOD)和过氧化氢酶(catalase,CAT)活性的影响。结果表明:SA处理显著降低李果实的冷害发生率和冷害指数(P<0.05),并推迟POD和PPO活性上升,延缓果肉褐变,减轻果实冷害现象,显著提高果实中SOD和CAT(P<0.05),维持较低水平的细胞膜渗透率和MDA含量,对细胞膜脂过氧化的发生起到一定的抑制作用。试验还发现:SA结合1-MCP处理显著抑制贮藏中期果实的冷害发生(P<0.05),但冷害积累速度高于SA处理,1-MCP处理加速了果实的冷害积累。上述结果表明,适宜浓度外源SA处理能够增强李果实采后的抗冷性,乙烯信号参与了该作用过程,但并非依赖性因素。

Ethylene Signals Involved in Salicylic Acid to Improve Cold Resistance of Postharvest Plum Fruits

In order to study the effect of salicylic acid on the cold resistance of postharvest plum fruits and its relationship with ethylene signal,in this study,medium-maturation(Bulang)plum fruits were used as materials. It were treated with 1.0 mmol/L SA and 1.0 μL/L 1-MCP separately and in combination,and treated with distilled water as a control group. The effects of the above treatment on the chilling injury rate,chilling injury index,peroxidase(POD),polyphenol oxidase(PPO),cell membrane permeability,malondialdehyde(MDA)content,superoxide dismutase(SOD)and catalase(CAT)activities of plum fruits under storage conditions at 4℃ were analyzed. The results showed that SA treatment could significantly reduce the chilling injury rate and chilling injury index(P<0.05),delay the increase of POD and PPO activity,delay flesh browning,mitigate chilling injury symptoms. Moreover,it could also augment the activities of SOD and CAT(P<0.05),and maintain lower levels of cell membrane permeability and MDA. Thereby,it had a certain inhibitory effect on the occurrence of cell membrane lipid peroxidation. The experiment also found that SA combined with 1-MCP treatment significantly inhibited the occurrence of chilling injury in the middle of storage(P<0.05),but the accumulation rate of chilling injury was higher than that of SA treatment,and 1-MCP treatment accelerated the accumulation of chilling damage. The above results indicate that the appropriate concentration of exogenous SA treatment can enhance the cold resistance of plum fruit after harvest,and ethylene signal participates in the process,but it is not a dependent factor.