增强UV-B辐射对芒果成年树光合作用及其产量与常规品质的影响

Effects of enhanced UV-B radiation treatment on photosynthesis,yield and conventional quality of adult mango tree

【目的】了解增强UV-B辐射对芒果成年树光合作用、产量和常规品质的影响,为制定芒果抗增强UV-B辐射栽培技术提供理论依据。【方法】以台农一号芒果成年树为试验材料,设6个增强UV-B辐射(采用UV-B紫外灯进行照射)处理(20、40、80、120、160和200 W),以自然光照射为对照(CK),测定分析各处理成熟叶片的光合指标、果实产量和常规品质。【结果】增强UV-B辐射处理芒果成熟叶片的叶绿素含量、类胡萝卜素含量、净光合速率(Pn)、蒸腾速率(Tr)和气孔导度(Gs)总体上均随增强UV-B辐射剂量的增加而下降,且表现增强UV-B辐射积累效应和剂量效应。160和200 W处理芒果的株产低于CK,其余增强UV-B辐射处理的株产与CK相当;可溶性糖含量、果实糖酸比和维生素C(Vc)含量总体上随增强UV-B辐射剂量的增加而降低,且除第2造果的200 W处理外其他处理果实的糖酸比、80 W以上处理的可溶性糖含量及120 W以上处理的Vc含量均显著低于CK(P<0.5,下同);可滴定酸含量总体上随增强UV-B辐射剂量的增加而升高,其中80 W以上处理显著高于CK。【结论】芒果成年树受增强UV-B辐射后其叶片光合作用受到抑制,果实可溶性糖含量、糖酸比和Vc含量降低,且具有增强UV-B辐射积累效应和剂量效应,引起果实减产和品质变劣。

【Objective】Effects of enhanced UV-B radiation treatments on the photosynthesis,yield and conventional quality of adult mango trees were studied to provide theoretical reference to formulate cultivation technology of the resistance of mango trees to enhanced UV-B radiation.【Method】Tainong No.1 mango adult tree was used as experiment material and treated（under 20,40,80,120,160 and 200 W）by six enhanced UV-B radiation（irradiation by UV-B）ultraviolet lamp）. And the sunlight irradiation was used as CK to measure and analyze the photosynthetic index of mature leaves,yield and ordinary quality of fruits.【Result】After treated by enhanced UV-B radiation,the contents of chlorophyll and carotenoid in the mature leaves of mango trees,net photosynthetic rate（Pn）,transpiration rate（Tr）and stomatal conductance（Gs）of mature mango leaves decreased with the increase of enhanced UV-B radiation,showing accumulation effects and dose effects of enhanced UV-B radiation. The yield of mango tree under treatment 160 and 200 W were lower than that of CK,while the yield of mango tree under other treatments made no obvious difference from that of CK. Content of soluble sugar,the ratio of sugar/acid in fruits and vitamin C（Vc）content decreased with the increase of the enhanced UV-B radiation amount. Meanwhile,the ratio of sugar/acid in fruits under all treatments except for the second harvest under 200 W treatment,content of the soluble sugar in fruits under treatment over 80 W and content of Vc in fruits under treatment over120 W were significantly less than those of CK（P〈0.05,the same below）. Content of titratable acids in fruits increased with the increase of the enhanced UV-B radiation intensity and was significantly more than that of CK when under the treatment over 80 W.【Conclusion】Photosynthesis of the mature leaves in adult mango trees can be inhibited under enhanced UV-B radiation,and content of soluble sugar,the ratio of sugar/acid in fruits and Vc content decrease. Accumulative effects and dose effects of enhanced UV-B radiation are presented which results in reducing yield and worsening fruit quality.