作 者 ：黄梅玲,江洪*,金清,余树全
期 刊 ：生态学报 2010年 30卷 8期 页码：1998~2009
关键词：UV-B辐射胁迫；木本植物；生长量；光合特征；进化；
Keywords:UV-B radiation stress, ligneous plants, growth increment, photosynthetic characteristic, evolution,
摘 要 ：平流层臭氧的减薄导致到达地表UV\|B辐射增强是全球所面临的环境问题之一。UV\|B辐射胁迫对植物的生物学效应研究成为继全球大气二氧化碳浓度升高对植物影响研究之后的又一热点领域。设置了UV\|B滤光减弱组、UV\|B辐射增强组和自然光对照组3组大田实验，选择不同起源时期的乐东拟单性木兰(Parakmeria lotungensi)、青冈(Cyclobalanopsis glauca)、山核桃(Carya cathayensis)幼苗为实验材料，测定每组中3种植物的生长量与光合特征参数，通过对比组间和种间差异，研究不同起源时期的3种木本植物对UV\|B辐射胁迫的响应模式，分析3种植物对于UV\|B辐射胁迫的适应性与自身起源和进化时间的关系，为“起源时间越早的木本植物生长发育和光合生理能否更好地适应UV\|B辐射胁迫”这一科学命题的探讨提供一定实验参考。得到如下结果：（1）相对于自然光照条件，增强UV\|B辐射胁迫对3种木本植物的地径和株高都有抑制作用；对乐东拟单性木兰、青冈的Pn和Amax有一定的抑制作用，对山核桃Pn和Amax则具有一定的促进作用。减弱UV\|B辐射胁迫对3种木本植物的地径起到抑制作用，对乐东拟单性木兰、青冈幼苗的株高生长有促进作用，但对山核桃的株高却具有抑制作用；对乐东拟单性木兰以及山核桃的Pn和Amax有一定的抑制作用，而对青冈Pn和Amax则有促进作用。（2）对比种间差异，发现3种不同的UV\|B光照条件下青冈的地径生长量都最大，乐东拟单性木兰次之，山核桃最小；株高生长量种间大小排序不一致；相对于自然光照条件，增强UV\|B辐射强度下山核桃Pn、Amax的比值都最大，青冈次之，乐东拟单性木兰最小；减弱UV\|B辐射强度下青冈的Pn、Amax的比值都最大，乐东拟单性木兰次之，山核桃最小；表明不同起源时间对植物抗UV\|B辐射胁迫能力有一定的影响，但不是决定性因素。UV\|B辐射增强和过滤减弱胁迫对3个树种幼苗的生长发育、光合作用、叶绿素均有影响，但不同起源时期3种木本植物幼苗光合特征参数的响应模式不一，其机制尚待进一步开展实验进行求证。本研究结果可丰富和补充UV\|B辐射胁迫对木本植物的影响研究，为从进化角度筛选UV\|B胁迫抗性较强的植物提供了一定的依据。
Abstract:Due to stratospheric ozone depletion, increase of solar UV\|B reaching the surface of the earth was one of the most important environment problems in the worldwide scope. Elevated solar UV\|B radiation exerted effects on plant through actions on photosynthetic system，protein，DNA, membrane system and phytohormone. The responses of plant physioecology and growth to ultraviolet radiation enhancement got more and more attention in the scientific community. Three treatments, including an exclusive UV\|B radiation group, an ambient UV\|B radiation group and a supplementary UV\|B radiation group were set up for the field experiment of Parakmeria lotungensi, Cyclobalanopsis glauca and Carya cathayensis seedlings originating from different time. The growth and photosynthetic parameters of three tree seedlings were measured under different solar UV\|B radiation conditions. Furthermore, the response of three tree seedlings originating from different time to UV\|B radiation stress were studied through comparing the difference of traits among the interspecies and groups. At last, the relationship between the adaptation capability and origin time of three tree seedlings was analyzed. It would provide the experiment reference data for the scientific proposition whether the characteristics of growth and photosynthetic physiology of more early evolutionary terrestrial plant groups should be well adapted to a high UV\|B radiation condition. The results indicated: (1) The height and diameter of three tree seedlings were impacted under the supplementary UV\|B radiation, Pn and Amax of Parakmeria lotungensi and Cyclobalanopsis glauca were inhibited while Carya cathayensis was promoted to compare with the ambient UV\|B radiation group (CK). The diameter of three tree seedlings were inhibited under the exclusive UV\|B radiation; only the height of Carya cathayensis was decreased while Parakmeria lotungensi and Cyclobalanopsis glauca were promoted; Pn and Amax of Parakmeria lotungensi and Carya cathayensis were decreased, while Cyclobalanopsis glauca was promoted. (2) The results of inter\|specific difference revealed that the diameter of Cyclobalanopsis glauca was increment and it was the biggest among three tree seedlings under three lighting conditions, followed were Parakmeria lotungensi and Carya cathayensis; the height increment of species order was not consistent; Compared with the ambient UV\|B radiation group, the ratios of Pn and Amax of Carya cathayensis under the supplementary UV\|B radiation were the biggest among three tree seedlings, followed were Cyclobalanopsis glauca and Parakmeria lotungensi; the ratios of Pn and Amax of Cyclobalanopsis glauca under the exclusive UV\|B radiation group were the biggest, followed were Parakmeria lotungensi and Carya cathayensis. It manifested that original time might have some influence on the resistance to UV\|B radiation stress, but the evolutionary was not the determining factor. The exclusive UV\|B radiation group and the supplementary UV\|B radiation group had an influence on the parameters of growth, photosynthetic activity and chlorophyll for three tree seedlings, but there were different patterns of three tree seedlings originating from different time. It is necessary to study the mechanisms by conducting more experiments in the future. The reported results would enrich and complement the response of woody species to UV\|B radiation stress, as well as provide information for selecting plant with strong resistance ability to UV\|B radiation stress.
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