摘要
采用开顶式有机玻璃罩(OTCs)及紫外灯分别模拟气候变暖和紫外辐射B(UV-B)增强,对位于气候变暖和UV-B增强突出的青藏高原东缘、高山峡谷地云杉(Picea asperata)幼苗的光合气体交换和叶绿素荧光参数进行测定分析,探讨云杉幼苗对气候变暖和UV-B增强的光合响应特性。结果显示:(1)UV-B辐射增强显著抑制了云杉幼苗茎和根的伸长生长以及生物量的累积,显著降低了云杉幼苗的净光合速率(Pn)、最大光合速率(Pmax)和表观量子产量(Φ),但是提高了光补偿点(LCP);UV-B辐射增强导致了云杉幼苗光合系统Ⅱ(PSⅡ)的光抑制,使PSⅡ有效量子产量(ΦPSⅡ)显著降低。(2)单纯OTC模拟增温显著提高了云杉幼苗的Pn和Pmax,而对气孔导度(Gs)、蒸腾速率(Tr)和Φ无显著影响。(3)模拟增温缓解了UV-B增强对云杉幼苗光合作用的抑制作用,显著提高了UV-B胁迫下幼苗的Pn、Pmax、PSⅡ的潜在量子效率(Fv/Fm)和有效量子产量(ΦPSⅡ),并且提高了UV-B胁迫下幼苗茎、根的生长以及生物量的累积。研究表明,在未来气候变暖和UV-B辐射增强同时存在时,气候变暖能够在一定程度上缓解UV-B增强对云杉林光合作用的抑制作用。
Using open-top Chambers（OTCs） and UV-lamps,we manipulated climate warming and enhanced UV-B radiation. The parameters of photosynthetic gas exchange and chlorophyll fluorescence of Picea as- perata seedlings in the eastern fringe of the Tibetan Plateau,where climate warming and enhanced UV-B radiation（UV-B） were severe,were measured to investigate its photosynthetic responses to the two worse- ning environmental factors. The results showed that： （1）Enhanced UV-B restrained the net photosynthetic rate （Pn）, the maximum photosynthetic rate（Pin,x） and the apparent quantum yield（Ф）. However,it increased the pho- tosynthetic light compensation point（LCP）. In addition,enhanced UV-B induced photo-inhibition of the photosyn- thetic system II（PS Il） in P. asperata seedlings, and it reduced the effective quantum yield of PS II（ФPSII ）. In the end,enhanced UV-B significantly inhibited shoot elongation, root growth and biomass accumulation. （2）OTCs warming significantly enhanced Pn and P but it had no effects on G ,Tr and Ф. （3）UV-B effects on pho- tosynthesis were amended by warming to some extent,which could be judging from the increased Pn ,P intrinsic effieiency（Fv/Fm） and ФPSII of PS II ,and the improved growth. In the end,warming could alleviate the harmful effects of enhanced UV-B on photosynthesis of P. asperata.
出处
《西北植物学报》
CAS
CSCD
北大核心
2014年第4期820-827,共8页
Acta Botanica Boreali-Occidentalia Sinica
基金
国家自然科学基金重点项目(30530630)
中国科学院知识创新工程重大项目(KSCX1-07-02-02)
“西部之光”人才计划资助项目(06C2051100)
关键词
气候变暖
UV—B辐射
云杉
光合作用
climate warming
UV-B radiation
Picea asperata
photosynthesis
