MeJA和乙烯利对鲜切山药伤害防御的响应

Stress Defense Response to Methyl Jasmonate(MeJA)and Ethephon for Cold Storage Fresh-cut Chinese Yam

以4℃冷藏条件下的鲜切山药为试验材料,研究在外源信号分子茉莉酸甲酯(MeJA)和乙烯利分别对冷藏鲜切山药伤害防御的响应。通过分析山药中过氧化氢酶(CAT)、过氧化物酶(POD)、抗坏血酸过氧化物酶(APX)、超氧化物歧化酶(SOD)和多酚氧化酶(PPO)活性随贮藏时间延长的变化规律,反映其伤害防御的响应效果。研究表明,经茉莉酸甲酯和乙烯利处理过的鲜切山药与对照组(CK)相比,显著提高SOD活性,降低CAT和APX活性下降速率,抑制PPO和POD催化山药组织中的酚类物质产生褐变现象,有效保持山药的色泽风味,延缓山药组织的衰老。乙烯利处理组后期不如茉莉酸甲酯处理组的防御效果好,可能是信号分子在果蔬不同部位的响应机制有所差异,从而造成防御响应结果不一致。茉莉酸甲酯和乙烯利处理均激发冷藏鲜切山药体内酶活性的协同效应,有效对机械损伤进行防御响应,而茉莉酸甲酯的诱导防御效果更为明显。

The response of exogenous signaling molecules,methyl jasmonate(MeJA)and ethephon to the injury defense of fresh-cut Chinese yam was studied.The changes of catalase(CAT),peroxidase(POD),ascorbic acid peroxidase(APX),superoxide dismutase(SOD)and polyphenol oxidase(PPO)activities with storage time were analyzed to reflect the response effect of injury defense.The results showed that fresh-cut Chinese yam treated with methyl jasmonate and ethephon significantly increased the activity of SOD(p<0.05),decreased the activity of CAT and APX,inhibited the browning of phenolic substances in Chinese yam tissues catalyzed by PPO and POD,effectively maintained the color and flavor of Chinese yam,and delayed the activity of CAT and APX.The defense effect of ethephon treatment was not as good as that of methyl jasmonate treatment at the later stage.It might be that the response mechanism of signal molecules in different parts of fruits and vegetables was different,which resulted in the inconsistency of defense response results.Both methyl jasmonate and ethephon treatment stimulated the synergistic effect of enzyme activity in fresh-cut Chinese yam stored in cold storage,effectively responded to mechanical damage,and methyl jasmonate induced defense effect was more obvious.