Guo Da-Gang, Li Fei, Gao Xiao-Dong, He Na-Na, Zhao Xi-Ning
Ministry of Education Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Northwest A&F University, Yangling 712100, Shaanxi, China; College of Water Resources and Architectural Engineering, Northwest A&F University, Yangling 712100, Shaanxi, China.
Ministry of Education Key Laboratory of Agricultural Soil and Water Engineering in Arid and Semiarid Areas, Northwest A&F University, Yangling 712100, Shaanxi, China; Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, Shaanxi, China.
Ying Yong Sheng Tai Xue Bao. 2022 Apr;33(4):995-1002. doi: 10.13287/j.1001-9332.202204.033.
Exploring the impacts of CO and soil water availability on the photosynthetic performance and water use efficiency of three green manure plants could provide theoretical basis for the adaptive management of grassland ecosystems under future climate change. An experiment was conducted in an artificial climate chamber with precisely controled CO concentrations of 400 (natural atmospheric) and 800 μmol·mol (doubled), and four water treatments, 80% field water holding capacity (FC) (full irrigation control group), 55%-60% FC (mild water deficit), 35%-40% FC (moderate water deficit), <35% FC (severe water deficit) to investigate the impacts of increasing CO concentration and water deficit on chlorophyll content, gas exchange variables, and water use efficiency (WUE) of oilseed rape (), white clover (), and alfalfa (). The results showed that under the same CO concentration, when soil moisture was less than 40% FC, the chlorophyll content and gas exchange parameters of three plants were significantly decreased. The treatment of 55%-60% FC did not alter the total chlorophyll content of three species, but reduced the photosynthetic rate () and transpiration rate () of white clover and alfalfa by 6%-25% and did not affect their WUE. Compared with atmospheric CO concentration, the doubled CO concentration significantly decreased the of oilseed rape by 21.5% under the full irrigation treatment, increased the of three species under mild water deficit, increased the of oilseed rape and alfalfa under moderate water deficit, but only improved the of alfalfa under severe water deficit. The doubled CO concentration significantly increased WUE of white clover and alfalfa under all water deficit conditions, but only increased WUE of oilseed rape under mild water deficit. Increasing CO concentration and water deficit significantly interacted to affect of three species and the WUE of oilseed rape. In summary, the three species differed in their responses to doubled atmospheric CO concentration and different levels of water deficit. Our results suggested that elevated CO concentration could improve the adverse effects of mild water deficit on photosynthetic performance and WUE of three species, but only improve the photosynthetic performance of alfalfa under severe water deficit.
探究一氧化碳（CO）和土壤水分有效性对三种绿肥植物光合性能及水分利用效率的影响，可为未来气候变化下草地生态系统的适应性管理提供理论依据。在人工气候箱中进行了一项实验，精确控制CO浓度为400（自然大气浓度）和800 μmol·mol（加倍浓度），并设置了四种水分处理，分别为田间持水量（FC）的80%（充分灌溉对照组）、55%-60% FC（轻度水分亏缺）、35%-40% FC（中度水分亏缺）、<35% FC（重度水分亏缺），以研究CO浓度升高和水分亏缺对油菜、白三叶和苜蓿叶绿素含量、气体交换参数及水分利用效率（WUE）的影响。结果表明，在相同CO浓度下，当土壤湿度低于40% FC时，三种植物的叶绿素含量和气体交换参数显著降低。55%-60% FC处理未改变三种植物的总叶绿素含量，但使白三叶和苜蓿的光合速率（Pn）和蒸腾速率（Tr）降低了6%-25%，且未影响其WUE。与大气CO浓度相比，加倍的CO浓度在充分灌溉处理下使油菜的Pn显著降低了21.5%，在轻度水分亏缺下提高了三种植物的Pn，在中度水分亏缺下提高了油菜和苜蓿的Pn，但仅在重度水分亏缺下提高了苜蓿的Pn。加倍的CO浓度在所有水分亏缺条件下均显著提高了白三叶和苜蓿的WUE，但仅在轻度水分亏缺下提高了油菜的WUE。CO浓度升高和水分亏缺对三种植物的Pn和油菜的WUE有显著的交互作用。总之，三种植物对大气CO浓度加倍和不同程度水分亏缺的响应存在差异。我们的结果表明，升高的CO浓度可改善轻度水分亏缺对三种植物光合性能和WUE的不利影响，但仅在重度水分亏缺下提高苜蓿的光合性能。
