滤除自然光中UV-B辐射成分对高山植物美丽风毛菊光合生理的影响  

Effects of UV-B exclusion on photosynthetic physiology in alpine plant Saussurea superba

作　　者：师生波[1,2] 尚艳霞[2] 朱鹏锦[2] 张德罡[1] 

机构地区：[1]甘肃农业大学草业学院,草业生态系统教育部重点实验室(甘肃农业大学),中-美草地畜牧业可持续发展研究中心,兰州730070 [2]中国科学院西北高原生物研究所,高原生物适应与进化重点实验室,西宁810001

出　　处：《植物生态学报》2011年第2期176-186,共11页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金资助项目(30670307、30570270和30170154);国际科技合作重点项目计划(2002CB714006)资助

摘　　要：采用滤除自然光谱中UV-B辐射成分的方法,探讨了高山植物美丽风毛菊(Saussurea superba)光合机构对青藏高原强UV-B辐射的响应和适应特性。结果表明,强太阳光中的UV-B成分能引起净光合速率的降低。连续16天不同天气下的观测表明,滤除UV-B处理时3min暗适应的光化学量子效率有升高的趋势;晴天下稳态光化学效率的分析也显示滤除UV-B处理的实际光化学量子效率和光化学猝灭系数有升高趋势,意味着自然光中的UV-B成分可限制美丽风毛菊叶片PSII反应中心的激发能捕获效率。PSII有效光化学量子效率的增加和非光化学猝灭系数的降低进一步表明,UV-B辐射能导致有效光化学效率的降低和非光化学能量耗散的增加。由上可知,自然强UV-B辐射是限制美丽风毛菊叶片光合作用的一个因素。滤除UV-B辐射处理对光合色素含量的影响较小,无论以叶面积还是叶鲜重为基础的滤除UV-B处理仅有微弱的增加趋势,说明强UV-B辐射具有加速光合色素的光氧化进程,促进细胞成熟和叶片衰亡的潜在作用。同样UV-B吸收物质的含量也几乎没有变化,表明强太阳辐射环境下生活的高山植物美丽风毛菊叶表皮层中已具有较多的紫外线屏蔽物质,足以抵御目前环境中强太阳UV-B辐射可能引起的伤害,较少受UV-B辐射波动的影响。Aims In the Qinghai-Tibet area, high levels of UV-B radiation reach the earth’s surface as part of strong solar radiation. It is therefore important to examine the response and adaptation of native alpine plants to strong UV-B radiation. Our objective was to determine the physiological response of the photosynthetic apparatus to current ambient UV-B intensity. Methods UV-B-exclusion experiments were conducted on a field site with UV-B-excluding and UV-B-trans-mitting filters. The two filters transmitted similar levels of photosynthetically active radiation, and there were no differences in air temperature and relative humidity under these metal-frame suspended plastic filters. The ex-periments were performed in alpine Kobresia humilis meadow with the native alpine species Saussurea superba. Pulse-modulated in vivo chlorophyll fluorescence was mainly used to obtain rapid information on UV-B effects on photosynthetic processes. The trials lasted 15 or 16 days during the growing season of July and August in 2008 and 2009. We measured the 3-min dark-adapted quantum efficiency of PSII photochemistry （F（v）/F（m））, PSII pho-tochemistry efficiency and photosynthetic gas exchange parameters under natural sunlight. The contents of pho-tosynthetic pigments and UV-B-absorbing compounds were analyzed in terms of both leaf area and leaf fresh weight units. Important findings Net photosynthetic rate, significantly increased after removal of UV-B components from natural sunlight. Although there was no significant difference, the F（v）/F（m） was increased in low UV-B treatment compared with the ambient UV-B control. Both the coefficient of photochemical quenching and actual photo-chemical efficiency of PSII in the light were higher in low UV-B treatment compared to ambient UV-B during the 16 days of continuous measurement during clear days. Variation of PSII maximum efficiency in the light and nonphotochemical quenching further confirmed that the decrease in PSII photochemistry efficiency and increase in nonpho

关 键 词：高山植物 叶绿素荧光 光化学效率 青藏高原 UV-B辐射 

分 类 号：Q945.11[生物学—植物学]