Stable isotope analyses of nitrogen source and preference for ammonium versus nitrate of riparian plants during the plant growing season in Taihu Lake Basin
Stable isotope analyses of nitrogen source and preference for ammonium versus nitrate of riparian plants during the plant growing season in Taihu Lake Basin
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太湖流域河岸植物生长季氮源及铵态氮与硝态氮偏好的稳定同位素分析
DOI：
10.1016/j.scitotenv.2020.143029
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发表时间：
2021
影响因子：
9.8
通讯作者：
Tang Sijing
中科院分区：
文献类型：
--
作者：
Qian Jin;Jin Wen;Hu Jing;Wang Peifang;Wang Chao;Lu Bianhe;Li Kun;He Xixian;Tang Sijing
植物是河岸带氮素循环的重要组成部分。了解河岸植物的氮素吸收策略，包括氮的来源和氮素形态的偏好(氨氮(NH_4+)与硝酸盐(NO_3-−))，对于加深我们对植物在调节河岸地区营养物质生物地球化学循环中的作用的认识是至关重要的。本研究在太湖流域植物生长季(6-9月)测定了3种河岸植物--芦笋、美人掌和芦荟的稳定氮同位素(δ15N)，以及不同来源的NH_4~+和NO_3的δ~(15)N和−。河水、地下水、雨水和土壤中的溶解无机氮(DIN)被认为是河岸生态系统中植物的主要氮源。结果表明，土壤是植物氮素营养的最大来源，土壤对植物氮素营养的贡献率在不同树种间差异显著(P<；P<0.05)，其贡献率分别为80.5%±24.1%、73.9%±22.8%和58.7%±66.1%。Calamus、C.India和P.南方种)。同时，复杂的水网、浅层地下水位和雨水中的高DIN含量导致了河流水、地下水和雨水对植物的氮贡献是不可忽视的。地下水对氮肥的贡献率较高。南方(12.8%±33.2%)Thana。Calamus(6.1±91.9%)ANDC。籼型(8.0%±11.5%)，这可能归因于更深的根OFP。澳大利亚人。在整个生长季节，所有植物对NO3-−表现出相似的氮素偏好。外部环境条件和植物特性以及对更丰富的土壤NO_3-−含量的适应是可能的解释。本研究可为河岸带生态恢复过程中的植被选择提供重要信息。合理的植被选择对植物生长和水质管理至关重要，特别是在农业流域，由于氮肥的广泛使用，农业流域的农业径流中氮含量相对较高。
Plants are vital components of the nitrogen (N) cycling in the riparian zones. Understanding of N uptake strategies of riparian plants, including N sources and preference in N forms (ammonium (NH4+) vs. nitrate (NO3−)), is essential to advance our knowledge on the role that plants play in regulating nutrient biogeochemical cyclings in the riparian areas. In this study, stable N isotopes (δ15N) of three riparian plants, includingAcorus calamus,Canna indicaandPhragmites australis, and theδ15Nof NH4+and NO3−in different sources were measured during the plant growing season (June–September) in the Taihu Lake Basin. The dissolved inorganic N (DIN) from river water, groundwater, rainwater and soil were considered as the major N sources for plants in the riparian ecosystem. Our results indicated that soil was the largest source for plant N nutrition, with significantly different (P< 0.05) contributions from soil observed among plant species (80.5 ± 4.1, 73.9 ± 2.8 and 58.7 ± 6.1% forA. calamus,C. indica, andP. australis, respectively). Meanwhile, complex water networks, shallow water tables, and high DIN content in rainwater lead to nonignorable N contributions from river water, groundwater and rainwater to plants. Groundwater contributed more percentage of N toP. australis(12.8 ± 3.2%) thanA. calamus(6.1 ± 1.9%) andC. indica(8.0 ± 1.5%), which is likely attributed to the deeper roots ofP. australis. All plants showed similar N preference for NO3−during the growing season. External environmental conditions and plant characteristics and adaption to more abundant soil NO3−content are possible explanations. Our research could provide important information for vegetation selections during the process of riparian ecological restoration. Reasonable choice of vegetation is essential to plant growth and water quality management, especially in agricultural watersheds where N concentrations are relatively high in agricultural runoff due to the wide uses of N fertilizers.