‘台农一号’芒果成年树在增强UV-B辐射处理下的损伤及其抗氧化响应

Damages and Responses on Antioxidance of ‘Tainong No 1' Mango Adult Trees Under Treatment of Enhanced UV-B Radiation

通过在花果生长发育期内连续对‘台农一号’芒果成年树进行人工模拟增强UV-B辐射处理,研究芒果成年树在不同剂量的增强UV-B辐射处理下的损伤及其抗氧化反应。以自然光照射为对照(CK),设置6个增强UV-B辐射处理水平(20、40、80、120、160、200 W),在田间对芒果成年树进行照射,田间测产和实验室测定成年叶生理生化指标,比较不同处理与CK的相互差异。160、200W处理株产低于CK,其余各处理株产均与CK无显著差异;叶片丙二醛(MDA)含量和相对电导率随增强UV-B辐射剂量的增加而升高,80W及以上辐射处理的MDA含量和相对电导率显著或极显著高于CK;叶片超氧化物歧化酶(SOD)、过氧化物酶(POD)、氧化氢酶(CAT)活性随增强UV-B辐射剂量的增加而呈先升高后降低的变化趋势,80 W及以上处理酶活性与CK差异显著或极显著;类黄酮、多酚、还原型谷胱甘肽(GSH)等含量随增强UV-B辐射剂量的增加而升高,维生素C含量则下降,上述4个指标的80W及以上处理与CK差异显著或极显著。80W增强UV-B辐射就能引起芒果树损伤,此后随着增强UV-B辐射剂量的增加而损伤愈趋严重,并表现出增强UV-B辐射处理的剂量效应和积累效应;叶片抗氧化生理生化指标除维生素C含量外均随着增强UV-B辐射处理剂量的增加而升高,进而尽量减轻活性氧损伤,并显示出剂量效应。

The antioxidance of ‘Tainong No 1＇ mango adult trees under different doses of enhanced UV-B radiation during the development of flowers and fruits was studied. The UV-B irradiation of the natural environment was used as the control group（CK）, and a series enhance UV-B irradiation（20, 40, 80, 120, 160, 200 W） was designed to treat the adult trees of ‘Tainong No.1＇ mango in the field. The yield of a single tree and the physiological and biochemical indexes of the adult leaves were detected and compared between the treatments and CK. The yields of the treatments 160 W and 200 W were lower than that of CK, and those of the other treatments was not significantly different from that of CK. The contents of MDA and the relative conductivity increased with the increase of the enhanced UV-B irradiation intensities, and the differences were significant between the treatments above 80 W and CK were significant or extremely significant. The activity of SOD, POD and CAT enzymes in leaves increased first and then decreased with the increase of UV-B irradiation, and the differences between the treatments above 80 W and CK were significant or extremely significant. The contents of the flavonoids, polyphenols, and reduced GSH increased with the increases of the enhanced UV-B irradiation, and those of vitamin C and carotenoids decreased, and the differences between the treatments above 80 W and CK were significant or extremely significant. The UV-B irradiation of 80 W could cause the damage of mango trees, after that, with the increase of UV-B irradiation dose, the damage became more serious, and showed an accumulation effect. In addition to the vitamin C content, the anti-oxidative physiological and biochemical indexes of leaves increased with the increase of the dosage of UV-B irradiation, thus minimizing the reactive oxygen damage and showing the dosage effect.