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酸雨胁迫对苦槠幼苗气体交换与叶绿素荧光的影响 被引量:25

Effects of acid rain stress on gas exchange and chlorophyll fluorescence of Castanopsis sclerophylla seedlings
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摘要 常绿阔叶树苦槠(Castanopsis sclerophylla)是亚热带地带性顶极群落的建群种之一,在区域森林资源保护和可持续利用方面具有重要的地位。在该区域日益严重的酸雨胁迫下,研究其对于胁迫的生理生态响应具有重要的理论价值和实践意义。该文以苦槠幼苗为研究材料,研究了酸雨胁迫对苦槠幼苗光合生理的影响。结果表明:(1)短时间内,pH2.5处理下的幼苗叶绿素相对含量最低,且与pH5.6处理下的存在显著性差异(p<0.05);经过一段时间处理后,pH4.0处理下的叶绿素相对含量最高,表明低浓度的酸雨会促进叶绿素相对含量的增加。(2)2007年4月,光合速率(Pn)、PSⅡ最大光化学效率(Fv/Fm)和PSⅡ的潜在活性(Fv/F0)在不同酸雨浓度处理下基本无变化。随着酸雨处理时间的延长,pH2.5处理下的Pn、光饱和点、光补偿点和暗呼吸速率有显著降低,且与pH5.6处理下的存在显著性差异(p<0.05)。pH2.5处理组与pH5.6处理组之间的Fv/Fm和Fv/F0差异性逐渐减小。表观量子效率和气孔导度变化规律不明显。综合来说,酸雨处理前期,高浓度的酸雨胁迫对苦槠幼苗叶绿素相对含量、光合生理参数有显著影响,但随着酸雨处理时间的增加,酸雨胁迫对苦槠幼苗的影响逐渐减小,表明其对外界不良环境具有一定的抵御能力和适应能力。 Aims Castanopsis sclerophylla is a constructive species in the zonal climax community of the subtropics. It is important for regional forest resource protection and sustainable use. With serious acid rain in this region,studies of physiological and ecological responses of C. sclerophylla to acid rain have important theoretical and practical value. My objective was to determine the effects of acid rain stress on photosynthetic and physiological characters of C. sclerophylla. Methods Three gradients of simulated acid rain treatments were applied to the species:pH = 2.5,4.0 and 5.6. Tests were done in April,July and October of both 2007 and 2008. Important findings In the pH 2.5 treatment,the relative chlorophyll content of C. sclerophylla seedlings was lowest during a short time,and there were significant differences between the pH 2.5 and 5.6 treatments (p 0.05). After a period of time for acid rain treatment processing,the relative chlorophyll content of C. sclerophylla seedlings was highest with pH 4.0,indicating that acid rain of low concentrations would increase the relative chlorophyll content. In April 2007,the net photosynthetic rate (Pn),maximal photochemical efficiency of photosystem II (Fv/Fm) and potential activity of photosystem II (Fv/F0) were almost unchanged under different acid rain treatments. With the extension of acid rain treatment,Pn,light compensation point (LCP),light saturation point (LSP) and dark respiration rate (Rd) were greatly reduced in the treatments with pH 2.5,and there were significant differences between the treatments with pH 2.5 and pH 5.6 (p 0.05). The differences of Fv/Fm and Fv/F0 between pH 2.5 and 5.6 were smaller than before. The changes of stomatal conductance (Gs) and apparent quantum yield (AQY) were not obvious. In the early phase of acid rain treatments,the high concentrations of acid rain stress significantly affected the relative chlorophyll content and photosynthetic physiological parameters,but with the processing of treatment,the effects of acid rain stress on C. sclerophylla seedlings reduced gradually,which showed that the seedlings have some resistance and adaptability to the detrimental environment stresses.
出处 《植物生态学报》 CAS CSCD 北大核心 2010年第9期1117-1124,共8页 Chinese Journal of Plant Ecology
基金 科技部973项目(2005CB422207和2005CB4-22208) 科技部国际合作项目(200073819) 国家自然科学基金项目(40671132) 国家科技部数据共享平台建设项目(2006DKA32300-08) 科技基础性工作专项(2007FY110300-08)资助
关键词 酸雨胁迫 苦槠幼苗 叶绿素荧光 气体交换 acid rain stress Castanopsis sclerophylla seedlings chlorophyll fluorescence gas exchange
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