植物叶片和植物个体的水-碳耦合及其关系  

Water-carbon Coupling of Plant Leaf and Whole-plant and Their Relationship

作　　者：郭鑫 张永娥 魏小燕 李永福 魏天兴[1] 张晓明[2] GUO Xin;ZHANG Yong-e;WEI Xiao-yan;LI Yong-fu;WEI Tian-xing;ZHANG Xiao-ming(School of Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;China Institute of Water Resources and Hydropower Research,Beijing 100038,China;Ningxia Soil and Water Conservation Monitoring Station,Yinchuan 750002,Ningxia,China)

机构地区：[1]北京林业大学水土保持学院,北京100083 [2]中国水利水电科学研究院,北京100038 [3]宁夏回族自治区水土保持监测总站,宁夏银川750002

出　　处：《地球科学与环境学报》2023年第4期991-1001,共11页Journal of Earth Sciences and Environment

基　　金：国家自然科学基金项目(51979290,51879281,42107375);宁夏回族自治区水利科技项目(SBZZ-J-2021-13);水利部重大科技项目(SKR-2022076)。

摘　　要：研究植物叶片和植物个体的水-碳耦合及其关系,可以为整合多尺度间水-碳耦合提供理论支撑,加深对植物生理调节适应的认识。以北京西山侧柏幼树为研究对象,设置3个大气CO_(2)浓度和5个土壤含水量梯度,在人工气候箱中进行控制试验;采用气体交换法、包裹式茎流计、静态同化箱等方法测定植物叶片和植物个体的固碳、耗水速率和光合生理特征,进而以水分利用效率为切入点,分析多尺度间水-碳过程及其耦合变化特征,探讨植物叶片和植物个体的水-碳耦合关系。结果表明:①除过量灌溉外,在其他土壤含水量条件下,植物叶片和植物个体蒸腾速率和净光合速率均随土壤含水量的增加而增大,其中蒸腾速率一般在大气CO_(2)浓度为400μmol·mol^(-1)时最大,净光合速率一般在大气CO_(2)浓度为800μmol·mol^(-1)时最大。②除严重干旱胁迫外,在其他土壤含水量条件下,植物叶片和植物个体瞬时水分利用效率均随土壤含水量的增加而降低;在相同土壤含水量条件下,植物叶片和植物个体瞬时水分利用效率均表现为在大气CO_(2)浓度为800μmol·mol^(-1)时最高;植物叶片与植物个体瞬时水分利用效率成极显著正相关关系。综上所述,高的大气CO_(2)浓度可缓解水分亏缺对植物叶片和植物个体光合生理过程的不利限制,提高其水分利用效率;在相同的时间尺度、种内冠层特性相似时,植物叶片瞬时水分利用效率可以较好地预测植物个体瞬时水分利用效率。The study on water-carbon coupling of plant leaf and whole-plant and their relationship can provide theoretical support for integrating water-carbon coupling among multiple scales,and deepen the understanding of plant physiological regulation of adaptation.Platycladus Orientalis saplings in the western mountains of Beijing were cultured in an artificial climate chamber with three atmospheric CO_(2) concentrations(C a)and five soil water content(SWC)gradients for interactive treatment.The carbon sequestration and water consumption rate,and the photosynthetic physiological characteristics of plant leaves and whole-plants were measured by exchange method,mini-lysimeters and static assimilation chamber;and then,the water and carbon processes of plant leaf and whole-plant and their coupling mechanism were analyzed with water use efficiency,and the relationship between water-carbon coupling of plant leaf and whole-plant was explored.The results show that①with the exception of excessive-watered,the transpiration rate and net photosynthetic rate of plant leaf and whole-plant increase with SWC;the transpiration rate is generally maximum at C a of 400μmol·mol^(-1),and the net photosynthetic rate is generally maximum at C a of 800μmol·mol^(-1);②the instantaneous water use efficiencies of plant leaf(WUE leaf)and whole-plant(WUE tree)decrease with the increase of SWC except for severe drought condition;under the same SWC condition,the WUE leaf and WUE tree reach maximum at C a of 800μmol·mol^(-1);the WUE leaf shows a highly significant positive correlation with WUE tree.In summary,high C a can offset the photosynthetic physiological impairment of plant leaf and whole-plant caused by restricted soilwater availability,and improve the water use efficiency of Platycladus Orientalis saplings.Within species,WUE leaf is a suitable predictor for WUE tree at the same time scale when canopy characteristics are similar.

关 键 词：水分利用效率 植物叶片 植物个体 CO_(2)浓度 土壤含水量 侧柏 光合生理 

分 类 号：Q948.1[生物学—植物学]