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两种豆科植物及各器官对不同形态氮的吸收、分配研究

摘要: 豆科植物在氮素缺乏的荒漠生态系统中大量存在,是该生态系统提供有效氮的中心, 也是这一区域重要的先锋物种。然而,到目前为止,针对荒漠生态系统豆科植物对氮素吸收 利用的研究还鲜见报道。本研究选择古尔班通古特沙漠广泛分布的弯花黄芪(Astragalus flexus)和镰荚黄芪(Astragalus arpilobus)为研究对象,分别在0 ~ 5、5 ~ 15 cm 土层添加 3 种不同形态氮(15N-NH4 +、15N-NO3 -、15N-Glycine),研究两种植物及各器官对不同形态氮 素的吸收、分配策略。结果表明:(1)在不同土层中,两种植物均偏好吸收硝态氮,且弯 花黄芪、镰荚黄芪对硝态氮的最高吸收速率分别为3.26、2.59 g g1 h1。(2)在不同土 层中,植物各器官间均对不同氮源吸收及分配有显著性差异(P 15N-Glycine > 15N-NH4 +,且硝态氮对 弯花黄芪氮素吸收的贡献率在37% ~ 41%之间,而对镰荚黄芪氮素吸收的贡献率最高可达 45%。(4)植物各器官间均对不同形态氮的回收率存在显著性差异(P 茎>根,而5 ~ 15 cm 土层中,弯花黄芪表 现为:叶>根>茎。总体上,在古尔班通古特沙漠生态系统中,不同生活型豆科植物对氮素 吸收及分配能力既有一致性也有差异性,且受到不同土壤深度、氮形态的影响。该结果为新 疆干旱、半干旱区豆科植物的氮吸收利用及分配提供理论依据。

Abstract: Legumes are abundant in the nitrogen deficient desert ecosystems, which is the center of supplying available nitrogen and the important pioneer species in this region. However, the studies on nitrogen uptake and utilization by leguminous in desert ecosystems have rarely been reported so far. In this study Astragalus flexus and Astragalus arpilobus, which are widely distributed in the Gurbantunggut desert, were selected as the research object. Three different nitrogen forms (15N-NH4 +、15N-NO3 -、15N-Glycine) were added to 0 ~ 5 and 5 ~ 15 cm soil layers, respectively, to study the absorption and distribution strategies of different forms of nitrogen in two plants and their organs. The results showed that: (1) In different soil layers, both plants preferred to absorb nitrate nitrogen, and the maximum absorption rates of Astragalus flexus and Astragalus arpilobus were 3.26、2.59 g g1 h1, respectively. (2) In different soil layers, there were significant differences in the uptake and allocation of different nitrogen sources among plant organs (P 15N-Glycine > 15N-NH4 +, and the contribution rates of nitrate nitrogen to nitrogen absorption of Astragalus flexus were ranged from 37% to 41%, while the maximum contribution rate to the nitrogen absorption of Astragalus arpilobus was 45%. (4) There were significant differences in recovery rates of different nitrogen forms between different organs of plants (P stem > root, while in the 5 ~ 15 cm soil layer, the rate was leaf > root > stem. In general, in the Gurbantunggut desert ecosystem, different life forms legumes had both consistency and difference in nitrogen uptake and allocation capacity, and were affected by different soil depths and nitrogen forms. The results provided theoretical basis for nitrogen uptake, utilization and allocation of legumes in arid and semi-arid regions of Xinjiang.

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[V1] 2023-05-21 20:03:59 ChinaXiv:202305.00172V1 下载全文
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