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;它降低青榨槭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.
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 UVoB 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 UVoB 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（ФPSП） 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.
出处
《应用生态学报》
CAS
CSCD
北大核心
2005年第9期1682-1686,共5页
Chinese Journal of Applied Ecology
基金
国家重点基础研究发展规划项目(G2000046802-05)
中国科学院知识创新工程重大项目(KSCX1-07-02)
国家"十五"科技攻关资助项目(2001BA606A-05-01).
关键词
UV-B辐射
青榨槭
生理生态
UV-B radiation, Acer davidii, Physiological response.
