毛乌素沙地典型固沙植物黑沙蒿和赖草叶片氮分配对最大净光合速率的影响  

Effect of leaf nitrogen allocation on maximum net photosynthetic rate of two common sand-fixing species,Artemisia ordosica and Leymus secalinus,in Mau Us Sandy Land

作　　者：赵洪贤 刘鹏 史曼英 徐铭泽 贾昕[1,2] 田赟 查天山[1,2] ZHAO Hong-Xian;LIU Peng;SHI Man-Ying;XU Ming-Ze;JIA Xin;TIAN Yun;ZHA Tian-Shan(School of Soil and Water Conservation,Yanchi Ecology Research Station of Mau Us Desert,Key Laboratory of State Forestry and Grassland Administration on Soil and Water Conservation,Beijing Forestry University,Beijing 100083,China;State Key Laboratory of Efficient Production of Forest Resources,Beijing 100083,China;Forest Seed and Seedling Management Station of Wudu District,Longnan,Gansu 746099,China;Observation and Research Station of Ecological Restoration for Chongqing Typical,Mining Areas Ministry of Natural Resources(Chongqing Institute of Geology and Mineral Resources),Chongqing 401120,China;College of Resources and Environmental Sciences,China Agricultural University,Beijing 100080,China)

机构地区：[1]北京林业大学水土保持学院,宁夏盐池毛乌素沙地生态系统国家定位观测研究站,北京林业大学水土保持国家林业和草原局重点实验室,北京100083 [2]林木资源高效生产全国重点实验室,北京100083 [3]陇南市武都区林木种苗管理站,甘肃陇南746099 [4]自然资源部重庆典型矿区生态修复野外科学观测研究站(重庆地质矿产研究院),重庆401120 [5]中国农业大学资源与环境学院,北京100080

出　　处：《植物生态学报》2025年第3期460-474,共15页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(32071842、32101588和32071843)。

摘　　要：探究气候变化背景下物种的适应机制是植物生理生态领域研究热点,研究半干旱区优势物种叶片氮分配对植物光合能力的影响,有利于理解气候变化背景下荒漠植物的适应能力。该研究于2021年5-10月,以宁夏盐池毛乌素沙地的主要建群种黑沙蒿(俗名:油蒿,Artemisia ordosica)和赖草(Leymus secalinus)为研究对象,通过测定黑沙蒿和赖草的光响应曲线、CO_(2)响应曲线和叶性状参数,计算叶片不同组分中的氮分配比例,结合同步观测的环境数据,探究两种固沙植物叶片氮分配相关参数对最大净光合速率(Amax)的影响。结果显示:在观测期内,黑沙蒿和赖草的单位质量叶片氮含量(Nmass)均值都为0.02 g·g^(-1),黑沙蒿Amax和叶氮在光合系统中的分配比例(Pp)均值分别为22.44μmol·m^(-2)·s^(-1)和42.9%,赖草Amax和Pp观测期内均值分别为11.99μmol·m^(-2)·s^(-1)和27.5%,相比黑沙蒿较低。在土壤水分亏缺的生长季中期,黑沙蒿Amax和Pp降低,而赖草的Amax和Pp并没有明显变化。相比于赖草,黑沙蒿Amax受叶片氮分配的影响更大,Pp和叶氮在羧化系统中的分配比例(Pc)分别是影响黑沙蒿和赖草Amax季节变异的主要叶片氮分配参数。在干旱胁迫期间,黑沙蒿和赖草叶片Nmass均降低,黑沙蒿叶片氮分配比例对土壤水分变化的敏感性较大,其光合氮利用效率(PNUE)降低,且投资更多的氮到非光合机构中来抵抗干旱,而赖草的叶片氮分配比例和PNUE的变化相对稳定,其Amax并没有显著下降。总之,黑沙蒿叶片对光合系统投入的氮比例相对较高,其光合能力在观测期内仍大于赖草。该研究表明,不同沙地物种对其生境的适应性存在差异,在未来干旱增加的条件下,该区域植被可能趋于以沙地灌木黑沙蒿为主的植被群落。Aims Studying the adaptation mechanisms of species in the context of climate change has been a concern in plant ecology.Investigating the effect of leaf nitrogen allocation of sand-fixing species on the photosynthetic capacity of plants help us to understand their adaptive capacity under changing climate.Methods In this study,we selected two common sand-fixing species,Artemisia ordosica and Leymus secalinus,in Yanchi,Northwest China.The effects of leaf nitrogen allocation on the maximum net photosynthetic rate(Amax)of the two species were analyzed using in situ measurements of photosynthetic light-and CO_(2)-response curves,leaf traits,and enviromental variables,from May to October,2021.Important findings The results showed that the mean leaf nitrogen content per unit mass(Nmass)was about 0.02 g·g^(-1)for both species.The mean values of Amax and the distribution proportion of leaf nitrogen in photosynthetic system(Pp)in A.ordosica were 22.44μmol·m^(-2)·s^(-1)and 42.9%,respectively.The mean values of Amax and Pp in L.secalinus were 11.99μmol·m^(-2)·s^(-1)and 27.5%,respectively,which were lower than those of A.ordosica.During the water deficit period in the middle growing season,Amax and Pp decreased in A.ordosica and remained relatively unchanged in L.secalinus.Comparing with L.secalinus,Amax of A.ordosica was more affected by leaf nitrogen distribution.The main controlling factors of Amax were Pp and leaf nitrogen distribution in carboxylation system(Pc)in A.ordosica and L.secalinus,respectively.In the middle growing season with low soil moisture,the Nmass decreased in both species.Photosynthetic nitrogen use efficiency(PNUE)decreased in A.ordosica due to its greater sensitivity of the nitrogen distribution ratio to soil moisture and more nitrogen investment in non-photosynthetic organisms and thus higher stress resistance,and remained relatively stable in L.secalinus.The Amax in A.ordosica was greater than L.secalinus during the observation period due to its relatively higher Pp.The differences between tw

关 键 词：半干旱区 叶片氮分配 光合氮利用效率 最大净光合速率 黑沙蒿 赖草 

分 类 号：Q945.78[生物学—植物学]