不同UV-B辐射对杧果树果实品质及其抗氧化的影响

Effects of Mango Trees Fruit Quality and Antioxidant Under Different UV-B Radiation Treatments

以‘台农一号’杧果树为试验材料,自然光为对照(CK),研究不同UV-B辐射[24、96 kJ/(m^2·d)]对杧果果实的损伤及其抗氧化的影响,并监测株产、果实品质和生理损伤、抗氧化保护机制等有关的生理生化指标的动态变化。结果表明:与CK相比,96 kJ/(m^2·d)的杧果树体株产和单果重均显著下降,其果实可溶性糖下降、可滴定酸含量升高继而糖酸比下降,导致果实品质变劣。2个UV-B辐射处理的果皮丙二醛含量与CK无显著差异,而果肉则显著高于CK。96 kJ/(m^2·d)处理的果皮维生素C和未知化合物含量均显著高于CK,而过氧化物酶(POD)活性显著低于CK,对其他抗氧化酶活性和还原性保护性成分含量则一直无显著影响。2个UV-B辐射处理的果肉抗氧化酶活性及还原型GSH含量随时间均呈先上升后下降的趋势。与CK相比,2个UV-B辐射处理的果肉超氧化物歧化酶和过氧化氢酶活性均显著下降,96 kJ/(m^2·d)处理的果肉POD活性、类黄酮和还原型GSH含量均显著低于CK,而24 kJ/(m^2·d)处理的POD活性与CK无显著差异,类黄酮和还原型GSH含量仅在后熟期显著低于CK,而多酚含量几乎不受影响。可见,增强UV-B辐射[96 kJ/(m^2·d)]对树体和果肉引起损伤,对果皮无损伤。

In order to evaluate the injures and responses of the anti-oxidation of mango fruits under two different doses of enhanced UV-B radiation treatments,the adult trees of the variety‘Tainong No.1’in the field were treated with enhanced UV-B radiation at the levels of 24 kJ/(m^2·d)and 96 kJ/(m^2·d),and those with natural sunlight were used as the control(CK).The dynamic changes of physiological and biochemical indexes related to plant yield,fruit quality and physiological damage,antioxidant protection mechanism,etc.were observed.The results showed that the yield per tree and single fruit weight of 96 kJ/(m^2·d)was significantly decreased compared with CK,and the fruit soluble sugar was decreased,titratable acid content was increased,and then the sugar-acid ratio was decreased,resulting in the fruit quality was worse.The content of MDA in the pericarp of two UV-B radiation treatments was not significantly different from CK,but the flesh was significantly higher than the CK.The contents of vitamin C and unknown compounds in pericarp treated with 96 kJ/(m^2·d)were significantly higher than the CK,while the POD activity was significantly lower than the CK,and there was no significant effect on the activity of other antioxidant enzymes and content of reductive protective components.The antioxidant enzyme activity and reduced GSH content of the flesh treated with two UV-B radiations increased first and then decreased with time.Compared with CK,the activity of SOD and CAT in the flesh treated with UV-B radiation were significantly decreased.POD activities,flavonoids and reduced GSH contents in the flesh treated by 96 kJ/(m^2·d)were significantly lower than the CK,while POD activities treated by 24 kJ/(m^2·d)showed no significant difference from CK.Flavonoids and reduced GSH contents was significantly lower than the CK only in the post-ripping stage,while polyphenol contents was almost unaffected.It can be seen that enhanced UV-B radiation[96 kJ/(m^2·d)]caused damage to the tree body and flesh,but no damage to the pericarp.