摘要
IPCC(Intergovernmental Panel on Climate Change)报告预测,到2100年CO_(2)浓度会出现430~480、580~720、720~1000和>1000μmol·mol^(-1)4种不同情景,而目前同时探究所有CO_(2)情景下植物响应情况的研究很少。本试验利用开顶式气室分别探究自然大气浓度(约400μmol·mol^(-1))、550、750和1000μmol·mol^(-1)4个CO_(2)水平在生长季内对一年生木荷(Schima superba)幼苗气体交换参数、光合色素含量及生物量的影响。结果表明:熏气期间,550、750和1000μmol·mol^(-1)浓度下木荷幼苗净光合速率分别平均提升32.7%、66.7%、82.7%,胞间CO_(2)浓度分别平均增加60.3%、126.2%、223.9%,而高浓度CO_(2)对净光合速率的提升作用随着熏气时间延长,可能受叶片氮含量减少等非气孔因素的影响而降低;3个高浓度CO_(2)处理下气孔导度和蒸腾速率在5—7月均增加,而1000μmol·mol^(-1)下气孔导度和蒸腾速率在8—10月逐渐下降到与自然大气无显著差别;5—10月1000和750μmol·mol^(-1)处理下叶绿素a、叶绿素b、类胡萝卜素含量和叶片N含量下降程度高于550μmol·mol^(-1)处理;熏气7个月后550和750μmol·mol^(-1)处理下木荷生物量分别提高79.2%和48.9%,而1000μmol·mol^(-1)处理下生物量减少。因此,高浓度CO_(2)处理有助于木荷幼苗对大气中CO_(2)进行固定及保存水分,从而增加木荷幼苗对干旱环境的适应性,同时550和750μmol·mol^(-1)浓度下有利于木荷生物量积累。
Few studies have explored plant responses to all of CO_(2) scenarios including 430-480,580-720,720-1000 and more than 1000μmol·mol^(-1) which will be by 2100 predicted by the IPCC(Intergovernmental Panel on Climate Change).In this study,one-year-old seedlings of Schima superba were exposed to ambient air and three elevated CO_(2) concentrations of 550,750,1000μmol·mol^(-1) to investigate the changes of gas exchange parameters,photosynthetic pigment contents,and biomass by using Open Top Chambers during growing season.The results showed that net photosynthetic rate was increased by 32.7%,66.7%,and 82.7%,and intercellular CO_(2) concentration was increased by 60.3%,126.2%,223.9%at 550,750,and 1000μmol·mol^(-1),respectively.The improvement in net photosynthetic rate under elevated CO_(2) concentrations decreased as affected by non-stomatal factors(such as decreased leaf N content)after longer fumigation time.Stomatal conductance and transpiration rate increased under all elevated CO_(2) concentrations from May to July,while there was no significant difference between 1000μmol·mol^(-1) and ambient treatments from August to October.The reduction of the contents of chlorophyll a,chlorophyll b,carotenoids,and N in leaves under 750 and 1000μmol·mol^(-1) was higher than that under 550μmol·mol^(-1).Biomass under the treatments of 550 and 750μmol·mol^(-1) increased by 79.2%and 48.9%,respectively,but decreased under 1000μmol·mol^(-1).Therefore,it would be beneficial for S.superba to fix the increasing CO_(2) in atmosphere and preserve water in body under elevated CO_(2) concentrations.These benefits would increase the adaptability of S.superba seedlings to arid environments and enhance biomass accumulation under CO_(2) concentrations of 550 and 750μmol·mol^(-1).
作者
潘鸿
曹吉鑫
陈展
尚鹤
PAN Hong;CAO Ji-xin;CHEN Zhan;SHANG He(Research Institute of Forest Ecology,Environment and Protection,Chinese Academy of Forestry,Key Laboratory of Forest Ecology and Environment of National Forestry and Grassland Administration,Beijing 100091,China)
出处
《生态学杂志》
CAS
CSCD
北大核心
2022年第5期865-872,共8页
Chinese Journal of Ecology
基金
国家重点研发计划子课题(2016YFD0600202-3)
国家自然科学基金项目(31800526)资助。
