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

[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.

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

[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 resis-tance 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 ca-rotenoid 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 radia-tion 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 over 120 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 en-hanced 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.