自然条件下胡杨叶片光合作用的气孔、非气孔限制  

Stomatal and no-stomatal limitations to photosynthesis of Populus euphratica leaves under natural conditions

作　　者：高冠龙[1,2,3] 冯起 刘贤德 GAO Guanlong;FENG Qi;LIU Xiande(Shanxi University,Taiyuan 030006,China;Shaanxi Key Laboratory of Land Consolidation,Xi'an 710075,China;Northwest Institute of Eco-Environment and Resources,CAS,Lanzhou 730000,China;Academy of Water Resources Conservation Forests in Qilian Mountains of Gansu Province,Zhangye 734000,China)

机构地区：[1]山西大学,太原030006 [2]陕西省土地整治重点实验室,西安710075 [3]中国科学院西北生态环境资源研究院,兰州730000 [4]甘肃省祁连山水源涵养林研究院,张掖734000

出　　处：《干旱区资源与环境》2020年第11期182-188,共7页Journal of Arid Land Resources and Environment

基　　金：山西省应用基础研究面上青年基金项目(201801D221286);中国博士后科学基金项目(2018M643769);中央高校基本科研业务费(自然科学类)资助项目(300102279505)共同资助。

摘　　要：文中分析了自然条件下胡杨叶片的外界环境因子及光合生理特征的日变化规律,探讨并剖析了自然条件下胡杨叶片光合作用的气孔和非气孔限制的特征。结果表明,在观测日内:1)净光合速率(Pn)总体呈先升高后降低的趋势,其中在6、8和9月正午前后出现了短暂的"光合午休"现象。气孔导度(gs)呈周期性波动,随着水汽压差(VPD)的增加而逐渐降低。胞间CO2浓度(Ci)基本呈现出早晚大、午间小的"V"型变化趋势。在所有观测日内,gs随着Pn的增大有增大的趋势。2)胡杨叶片光合作用的气孔限制值(Ls)在早上水平较低,在中午和下午呈现出相对较高水平;非气孔限制值(Ci/gs)水平在上午较小,下午慢慢增大,在16:00前后迅速升高。在"光合午休"时间段内,首先Ls逐渐升高并达到最大值,而此时Ci达到最低值,表现出明显的气孔限制。随后Ls逐渐减小而Ci/gs迅速升高,表现出明显的非气孔限制。3)相对气孔限制值(RLs)与Ls的变化趋势一致,可以反映气孔控制光合作用过程的相对重要性,但其值在下午略低于Ls,说明气孔限制因子在下午对光合作用的影响程度下降。In this paper,we analyzed diurnal variations of environmental and physiological factors of Populus euphratica leaves under natural conditions,and discussed characteristics of values of stomatal and non-stomatal limitations to photosynthesis.Results showed that in the observational days:(1)net photosynthetic rate(Pn)increased firstly,and then decreased.There was obvious phenomenon of"Midday Depression of Photosynthesis"(MDP)around noon in June,August and September.Stomatal conductance(gs)fluctuated periodically,it decreased with the enhancement of VPD.Sub-stomatal CO2 concentrations(Ci)showed a"V-shape"curve,it peaked in the morning or afternoon.In all the observational days,gs increased with the increase of Pn.(2)Values of stomatal limitation to photosynthesis(Ls)in the morning were lower than those at noon and in the afternoon,while the values of non-stomatal limitation to photosynthesis(Ci/gs)in the afternoon were much greater than those in the morning,and Ci/gs increased rapidly after 16:00.At the beginning of MDP,Ls peaked where its predominance was supported by Ci being at a minimum,stomatal limitation to photosynthesis was apparent.Thereafter,Ls decreased and Ci/gs increased sharply,indicating that the non-stomatal limitation to photosynthesis predominated.(3)The variations of relative stomatal limitation to photosynthesis(RLs)were agreed with those of Ls,and can be used to quantify the relative importance of the stomata in controlling the processes of photosynthesis.However,the RLs values in the afternoon were slightly lower than those of Ls,and this indicated that stomatal limitation factors had a decreased effect on photosynthesis in the afternoon.

关 键 词：光合作用 气孔限制 非气孔限制 胡杨 

分 类 号：Q945[生物学—植物学]