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短期增强UV-B辐射对青榨槭幼苗生理特性的影响

左园园1,2 刘庆1 林波1 何海1,3   

  1. 1中国科学院成都生物研究所,成都 610041;2中国科学院研究生院,北京 100039;3重庆师范大学,重庆 400047
  • 收稿日期:2004-11-17 修回日期:2005-04-01 出版日期:2005-09-18

Physiological responses of 2-year-old Acer davidii seedlings to short-term enhanced UV-B radiation

ZUO Yuanyuan 1,2,LIU Qing 1,LIN Bo 1,HE Hai 1,3   

  1. 1Chengdu Institute of Biology,Chinese Academy of Sciences,Chengdu 610041,China;2Graduate School of Chinese Academy of Sciences,Beijing 100039,China;3 Chongqing Normal-University,Chongqing 400047,China

  • Received:2004-11-17 Revised:2005-04-01 Online:2005-09-18

摘要: 在中国科学院茂县生态站选择2年生青榨槭幼苗进行室外盆栽实验,以人工增强0.27 W·m-2(7.7 kJ·m-2·d-1)的UV-B辐射剂量,研究模拟当地平流层臭氧削减15%时近地面太阳UVB的增强对木本植物幼苗生理生态适应性的影响.处理50 d后,移除UV-B处理装置,就地测定气体交换参数和叶绿素荧光参数,并取样测定叶绿素及UV吸收物质含量.结果表明,增强UV-B辐射显著降低了青榨槭幼苗叶片最大净光合速率Pmax(对照为6.214,处理为4.452),显著增加叶片暗呼吸速率Rd(对照为0.413,处理为1.295)和光补偿点LCP(对照为21.629,处理为59.861),但对表观量子速率a(对照为0.021,处理为0.032)影响不明显;它降低青榨幼苗每日净光合速率和水分利用效率,以及原初光化学效率(Fv/Fm)和实际光化学量子产量(ΦPSП).此外,增强UV-B辐射使叶片叶绿素a、b含量降低(对照为16.23,5.39,处理为13.17,4.93),但对叶绿素b含量影响未达显著水平.增强UV-B处理降低了青榨槭幼苗UV吸收物质含量(对照为0.87,处理为0.79).光合指标、叶绿素荧光指标和叶绿素含量的变化有较好的一致性,表明增强UV-B对青榨槭幼苗的光合作用可能有一定的抑制作用.

关键词: 了哥王, 生物量, 光合速率, 形态特征, 营养成分

Abstract: At the Maoxian Ecological Experimental Station of Chinese Academy of Sciences in northwest Sichuan Province,2-year-old native maple(Acer davidii) seedlings were potted outdoors with enhanced UV-B radiation(280~320 nm) of 0.27 W·m-2(7.7 kJ·m-2·d-1),which was approximated to the predicted enhanced UV-B reaching the earth surface when stratosphere ozone was depleted by 15% in the local area,with the control plant received ambient UV-B.The gas exchange index and chlorophyll fluorescence,and the contents of chlorophyll and UV-absorbing compounds were examined after 50 days of the radiation.The results showed that enhanced UV-B radiation significantly lowered the maximal net photosynthetic rate(CK=6.214,TR=4.452),raised the dark respiration rate(CK=0.413,TR=1.295) and light compensation point(CK=21.629,TR=59.861),but had little effect on quantum yield(CK=0.021,TR=0.032).Under enhanced UV-B radiation,the diurnal changes in net photosynthetic rate,water use efficiency,quantum efficiency of photosystem Ⅱ centers(Fv/Fm),and quantum yield of photosystem Ⅱ photochemistry (ΦPSП) were reduced,chlorophyll a,total chlorophylls, and chlorophyll a/b(CK=16.23,5.39,TR=13.17,4.93) were also markedly reduced,but chlorophyll b remained nearly unchanged.Contrary to the previous studies,enhanced UV-B radiation decreased the content of UV-absorbing compounds(CK=0.87,TR=0.79) in 2-year-old Acer davidii seedling leaves,indicating that the measurement of leaf UV-B absorbing compounds didn't necessarily provide a good indicator of plant tolerance to UV-B.It could be concluded that enhanced UV-B radiation had some inhibitory effects on the photosynthesis of Acer davidii seedlings.Long-term researches are necessary to confirm this conclusion.

Key words: Wikstroemia indica, Biomass, Photosynthetic rate, Morphological characteristics, Nutrient composition