摘要
【目的】研究极端干旱条件下岩溶区不同植物的叶片生理特征和氢氧稳定同位素特征,为岩溶区应对气候变化、石漠化治理及生态系统的可持续发展提供理论依据。【方法】在2022年极端干旱条件下,选取漓江流域核心区域浪石地下河流域(上游为非岩溶区)和麻山庙地下河流域(全为岩溶区)为研究区域,以该区域典型植物沙糖橘、桂花树、构树和黄荆为研究对象,对4种植物叶片的生理特征(净光合速率、蒸腾速率、胞间CO_(2)浓度、水分利用效率)开展野外实地监测,利用液态水同位素分析仪分析植物叶片氢氧稳定同位素特征,探讨极端干旱条件下岩溶区植物的水分利用策略。【结果】浪石地下河流域4种植物的净光合速率均值[11.27μmol/(m^(2)·s)]和水分利用效率均值(3.65μmol/mmol)高于麻山庙地下河流域,麻山庙地下河流域的胞间CO_(2)浓度均值(264.36μmol/mol)高于浪石地下河流域,2个流域间4种植物蒸腾速率的空间差异较小。在植物叶片水氢氧稳定同位素空间分布中,浪石地下河流域桂花树、构树、黄荆的叶片水氢氧稳定同位素均高于麻山庙地下河流域,沙糖橘叶片水的氢稳定同位素(δ^(2)H)表现为浪石地下河流域高于麻山庙地下河流域,氧稳定同位素(δ^(18)O)则具有相反的空间分布格局。4种植物的叶片水氢氧稳定同位素动力分馏效应由强到弱依次为沙糖橘(0.89)、黄荆(0.90)、桂花树(1.40)和构树(1.52)。不同植物的氘盈余(d-excess)与叶片水氢氧稳定同位素均呈负相关。【结论】漓江流域极端干旱条件下,浪石地下河流域植物水分利用效率较高,叶片水氢氧稳定同位素富集。沙糖橘主要依赖人为供水干预,抗旱能力较弱;桂花树和构树通过较低的动力分馏效应和较高的水分利用效率表现出较强的干旱适应性;黄荆通过最低的水分利用效率和氢氧稳定同位素来适应干旱环境,体现灌木在岩溶山区的较强抗旱能力。
【Objective】The study aimed to study of leaf physiological properties and characteristics of hydrogen and oxygen stable isotopes of different plants in karst areas under extreme drought conditions,so as to provide a theoretical basis to cope with climate change,rocky desertification for the sustainable development of ecosystem of karst area.【Method】Under the extreme drought conditions of 2022,the Langshi Underground River Basin(non-karst upstream area)and the Mashanmiao Underground River Basin(wholly karst areas)in the core region of the Lijiang River Basin were selected as study areas.Using typical plants in these regions—Shatang mandarin,Osmanthus fragrans,Broussone-tia papyrifera,and Vitex negundo as study subjects,field monitoring was conducted on leaf physiological properties of different plants(net photosynthetic rate,transpiration rate,intercellular CO_(2) concentration,and water use efficiency).Liquid water isotope analyzer were used to assess characteristics of hydrogen and oxygen stable isotopes in plant leaf to discuss water use strategies of karst plants under extreme drought conditions.【Result】The average net photosynthetic rate[11.27μmol/(m^(2)·s)]and average water use efficiency(3.65μmol/mmol)of four plant species in the Langshi Underground River Basin were higher than those in the Mashanmiao Underground River Basin;the average intercellular CO_(2) concentration in the Mashanmiao Underground River Basin(264.36μmol/mol)was higher than that in the Langshi Underground River Basin;the spatial difference in transpiration rates of the four plants between the two river basins was relatively small.In the spatial distribution of hydrogen and oxygen stable isotopes in plant leaf water,the hydrogen and oxygen stable isotopes in leaf water of Osmanthus fragrans,Broussonetia papyrifera,and Vitex negundo in the Langshi Underground River Basin were higher than that of Mashanmiao Underground River Basin;the hydrogen stable isotope(δ^(2)H)in leaf water of Shatang mandarin was higher than that in the Langshi Underground River Basin compared to the Mashanmiao Underground River Basin,while the oxygen stable isotope(δ^(18)O)exhibited the opposite spatial distribution pattern.The kinetic fractionation effects of hydrogen and oxygen stable isotopes of leaf water in four plants,ranked from strongest to weakest as follows:Shatang mandarin(0.89),Vitex negundo(0.90),Osmanthus fragrans(1.40),and Broussonetia papyrifera(1.52).The deuterium excess(d-excess)of different plants was negatively correlated with hydrogen and oxygen stable isotopes in leaf water.【Conclusion】Under the extreme drought conditions,water use efficiency of plants in the Langshi Underground River Basin,and enrichment of hydrogen and oxygen stable isotopes in leaf water is more pronounced.The Shatang mandarin mainly relies on artificial water supply intervention and has a weak drought to-lerance.Osmanthus fragrans and Broussonetia papyrifera adapt well to drought through lower kinetic fractionation effects and higher water use efficiency.Vitex negundo adapts to drought environments through its lowest water use efficiency and hydrogen and oxygen stable isotopes,reflecting a stronger drought tolerance of the shrub in karst mountainous areas.
作者
赵欣滢
陈展图
黄芬
孙平安
郭永丽
刘绍华
汤庆佳
苗迎
肖琼
ZHAO Xin-ying;CHEN Zhan-tu;HUANG Fen;SUN Ping-an;GUO Yong-li;LIU Shao-hua;TANG Qing-jia;MIAO Ying;XIAO Qiong(Institute of Karst Geology,Chinese Academy of Geological Sciences/Key Laboratory of Karst Dynamics,Ministry of Natural Resources&Guangxi/International Research Center on Karst under the Auspices of UNESCO,Guilin,Guangxi 541004,China;College of Environment and Resources,Guangxi Normal University,Guilin,Guangxi 541006,China;Pingguo Guangxi,Karst Ecosystem,National Observation and Research Station,Baise,Guangxi 531406,China)
出处
《南方农业学报》
北大核心
2025年第10期3163-3175,共13页
Journal of Southern Agriculture
基金
广西科技计划项目(桂科AB25069498)
广西自然科学基金项目(2022GXNSFAA035604)
国家外国专家项目(DL2023055001L)
中国地质调查项目(DD20230547)。
关键词
漓江流域
极端干旱
植物叶片水
氢氧稳定同位素
氘盈余
Lijiang River Basin
extreme drought
plant leaf water
hydrogen and oxygen stable isotopes
d-excessFoundation
