中国生态农业学报2017，Vol.25Issue(5)：708-719,12.DOI:10.13930/j.cnki.cjea.160801
全生育期UV-B辐射增强对棉花生长及光合作用的影响
Effect of enhanced UV-B radiation on cotton growth and photosynthesis
摘要
Abstract
It has been shown that the thinning of ozone layer continuously enhances ambient ultraviolet-B (UV-B) radiation. En-hanced UV-B radiation influences the growth, development and metabolism of crops, of which photosystem is the initial and most important target. In this study, UV-B radiation was increased by 20% and 40% by using ultraviolet lamp during the whole growth period of cotton under field condition, and its effect on cotton morphology, dry matter accumulation, photosynthetic pigment content and seed cotton yield were analyzed. The influencing mechanism of enhanced UV-B radiation on photosynthesis was also investigated by determining gas exchange parameters and chlorophyll fluorescence parameters in functional leaves. The results showed that the growth of cotton stems, leaves and dry matter accumulation were significantly inhibited by enhanced UV-B ra-diation. The inhibition effects of enhanced UV-B radiation on cotton were more obvious at seedling stage than that at later growth stages. Seed cotton yield also remarkably decreased with increasing UV-B radiation. The contents of chlorophyll a (Chla) and chlorophyll b (Chlb) increased under the treatment of 20% above ambient UV-B radiation and there was no change in Chla/Chlb. When UV-B radiation increased to 40% above ambient UV-B radiation, Chla, Chlb and Chla/Chlb significantly decreased. With increasing UV-B radiation, net photosynthetic rate (Pn) of functional leaves on cotton main stem significantly decreased. Although there were no change in stomatal conductance (Gs) and transpiration rate (Tr) under 40% increase in UV-B radiation, while inter-cellular CO2 concentration (Ci) increased, which indicated that the decline in photosynthesis was mainly caused by non-stomatal limitation factors. The results of chlorophyll fluorescence parameters analysis showed that with increasing UV-B radiation, maximum quantum efficiency (Fv/Fm), operating efficiency (ΦPSⅡ), linear electron transport rate (ETR) and photochemical quenching (qP) of PSIIremarkably decreased, but non-photochemical quenching (NPQ)increased. All the chlorophyll fluores-cence parameters were significantly correlated withPn changes. Slowly relaxing NPQ (NPQS) and its proportion in NPQ signifi-cantly increased under enhanced UV-B radiation, which indicated that the photochemical efficiency of PSⅡ decreased as its reaction center was damaged by elevated UV-B radiation. The results demonstrated that photosynthetic leaf area, chlorophyll content and photosynthetic rate of cotton dropped under enhanced UV-B radiation during the cotton growth period. This inhibited cotton growth, material accumulation and seed cotton yield. Decrease inPn due to enhanced UV-B radiation was closely related with the destruction of PSⅡ reaction center.关键词
UV-B辐射增强/棉花生长/气体交换/光系统Ⅱ(PSⅡ)/叶绿素荧光参数/慢速弛豫NPQKey words
Enhanced UV-B radiation/Cotton growth/Gas exchange/PhotosystemⅡ (PSⅡ)/Chlorophyll fluorescence pa-rameters/Lowly relaxing NPQ分类
农业科技引用本文复制引用
祁虹,段留生,王树林,王燕,张谦,冯国艺,杜海英,梁青龙,林永增..全生育期UV-B辐射增强对棉花生长及光合作用的影响[J].中国生态农业学报,2017,25(5):708-719,12.基金项目
国家自然科学基金项目(31171491)和现代农业产业技术体系建设专项资金(CARS-18-21)资助 This work was supported by the National Natural Science Foundation of China (31171491) and the Special Fund for the Industrail Technol-ogy System Construction of Modem Agriculture (CARS-18-21). （31171491）
