5个常见绿化树种对极端高温的光合响应特征  

Photosynthetic characteristics of five common tree species in response to extreme heat

作　　者：张宇鹏[1,2] 周国模[1,2] 周宇峰[1,2] 施拥军[1,2] 李翀[1,2] 李梦[1,2] 吕玉龙[3] 何莹[3] 

机构地区：[1]浙江农林大学浙江省森林生态系统碳循环与固碳减排重点实验室,浙江临安311300 [2]浙江农林大学亚热带森林培育国家重点实验室培育基地,浙江临安311300 [3]浙江省安吉县林业局,浙江安吉311300

出　　处：《浙江农林大学学报》2017年第2期301-309,共9页Journal of Zhejiang A&F University

基　　金：国家自然科学基金重大项目(61190114/F0102);国家自然科学基金资助项目(31070564;61303236);国家林业局引进国际先进农业科学技术计划("948"计划)项目(2013-4-71);浙江省科技计划项目重大科技专项(2012C13011-1)

摘　　要：光合作用对环境因子的响应高度敏感,同时也相应地受到环境因子不同程度的影响。利用LCPRO+便携式光合测定仪,在2013年8月高温夏季和2014年8月正常夏季气温下测定浙北地区5个常见绿化树种(银杏Ginkgo biloba,樟树Cinnamomam camphora,乐昌含笑Michelia chapensis,广玉兰Magnolia grandiflora,玉兰Magnolia denudata)气体交换特征,研究极端高温天气对其光合作用日变化特征的影响。结果表明:不同树种对极端高温天气的光合响应特征存在差异,但变化趋势相同,正常夏季在12:00左右出现光合"午休",极端高温天气在8:00左右出现光合"午休"之后净光合速率(Pn)保持较低水平并无午休恢复现象。2013年高温造成蒸腾速率(Tr)升高,气孔导度(Gs)迅速下降,5树种较低的Pn值以及较高的胞间二氧化碳摩尔分数(Ci)等说明高温降低了树种叶片光合作用酶促反应活性。分析2013年和2014年不同树种光合生理参数发现,不同树种间光合生理差异受到树种叶片Ci的影响显著(P<0.05),环境因子对不同树种光合作用参数Pn(P<0.01),Tr(P<0.05),Gs(P<0.02)造成的影响显著。水分利用效率(EWUE)变化幅度最小的是樟树(20.32%),达到35℃最适气温时樟树Pn值明显高于其他树种,结合Pn值光响应曲线认为樟树较其他试验树种更能够适应极端高温天气。Plant photosynthesis is most sensitive to environmental factors and physiological processes, and it is subject to varying degrees of external environmental impacts. In August 2013 with high summer temperatures and in August 2014 with normal summer temperatures, daily dynamics of photosynthetic characteristics in five common tree species（Ginkgo biloba, Cinnamomam camphora, Michelia chapensis, Magnolia grandiflora, Magnolia denudata） were monitored using a Portable LCPRO＋ Photosynthesis System（LCPRO＋, ADC Bioscientific）. Results showed that with extremely hot temperatures photosynthetic response characteristics of different species differed, but overall they had the same pattern. In a normal summer the ＂ midday depression＂ appeared around 12：00 noon, but for extremely high temperatures it occurred around 08：00 with the net photosynthetic rate（Pn） remaining low after noon and having no recovery phenomenon. In 2013 elevated temperatures caused the transpiration rate（Tr） and stomatal conductance（Gs） to decrease rapidly with all five species having lower Pnand higher intercellular CO2concentration（Ci）. For photosynthetic parameters, analysis of species in different years showed that physiological differences between different species were significantly influenced by Ci（P〈0.05）; whereas, the impact of environmental factors on photosynthetic parameters showed significance with Pn（P〈0.01）, Tr（P〈0.05）, and Gs（P〈0.02） in different species. For ecosystem water use efficiency（EWUE） the smallest change was with camphor trees（20.3%）. When the temperature reached the optimum temperature of 35 ℃, camphor Pnwas significantly higher than the other species. Thus, the camphor tree was more able to adapt to extremely hot weather than other test species.

关 键 词：植物生理学 绿化树种 光合速率 极端高温 光合“午休” 

分 类 号：S718.43[农业科学—林学]