热水处理诱导香蕉采后抗病性及其对相关酶活性的影响

Hot water dipping induced resistance to disease Colletotrichum musae on banana fruits and its effect on related enzymes

该文探讨了热处理对采后香蕉果实软化、褪绿转黄、炭疽病病斑大小及相关防御酶活性变化的影响。香蕉果实用52℃热水处理10min后在25℃下贮藏,在12d内果实软化和褪绿转黄不明显,而未经热处理的对照果实在12d内明显软化和转黄。接种外源炭疽菌孢子可促进果实的软化和褪绿,但热处理果实的软化和褪绿速度仍然慢于对照果实。接种炭疽菌孢子后,对照果实病斑扩展迅速,而热处理果实病斑扩展缓慢。热处理导致果皮多酚氧化酶(PPO),过氧化物酶(POD)和超氧化歧化酶(SOD)活性的下降,诱导了酯氧合酶(LOX)活性大幅度提高,对苯丙氨酸解氨酶(PAL)活性影响不显著。这些结果表明,热处理可诱导采后香蕉的抗病性并具有一定延缓果实后熟的作用。该文还对香蕉果实抗病性的提高与相关防御酶活性的关系进行了讨论。

The influences of hot water dipping treatment on fruit softening, degreening, size of lesion, activities of several relevant defense enzymes in postharvest banana fruit were investigated. Softening and degreening are not evident for the fruits treated with 52℃ hot water dipping（HWD） for 10 min, and stored at 25℃（2 for 12 days, while the control fruit softens and degreens obviously under the same condition. Inoculating fruit with spore suspension of Colletotrichum musae softening and degreening process of the control fruit is accelerated and its size of lesion expands quickly, whereas HWD treated fruit presents slower softening, degreening and lesion expansion. Compared with the control, in the peel of HWD treated fruit, the activities of Polyphenol Oxidase（PPO）, Peroxidase（POD） and Superoxide Dismutase（SOD） decrease, the activity of Phenylalanine Ammonialyase（PAL） displays no difference, while the activity of Lipoxygenase（LOX） increases dramatically. The above results indicate that HWD treatment delays fruit ripening and induces disease resistance of banana fruit. The relationship between the increased disease resistance and the activities of the relevant enzyme was discussed.