Huang Yulin, Du Liushan, Lei Yanbao, Liang Jiye
China-Croatia "Belt and Road" Joint Laboratory on Biodiversity and Ecosystem Services, CAS Key Laboratory of Mountain Ecological Restoration and Bioresource Utilization & Ecological Restoration and Biodiversity Conservation Key Laboratory of Sichuan Province, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu 610041, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Plants (Basel). 2023 Feb 13;12(4):838. doi: 10.3390/plants12040838.
Plant nitrogen (N) uptake preference is a key factor affecting plant nutrient acquisition, vegetation composition and ecosystem function. However, few studies have investigated the contribution of different N sources to plant N strategies, especially during the process of primary succession of a glacial retreat area. By measuring the natural abundance of N isotopes (δN) of dominant plants and soil, we estimated the relative contribution of different N forms (ammonium-NH, nitrate-NO and soluble organic N-DON) and absorption preferences of nine dominant plants of three stages (12, 40 and 120 years old) of the Hailuogou glacier retreat area. Along with the chronosequence of primary succession, dominant plants preferred to absorb NO in the early (73.5%) and middle (46.5%) stages. At the late stage, soil NH contributed more than 60.0%, In addition, the contribution of DON to the total N uptake of plants was nearly 19.4%. Thus, the dominant plants' preference for NO in the first two stages changes to NH in the late stages during primary succession. The contribution of DON to the N source of dominant plants should not be ignored. It suggests that the shift of N uptake preference of dominant plants may reflect the adjustment of their N acquisition strategy, in response to the changes in their physiological traits and soil nutrient conditions. Better knowledge of plant preferences for different N forms could significantly improve our understanding on the potential feedbacks of plant N acquisition strategies to environmental changes, and provide valuable suggestions for the sustainable management of plantations during different successional stages.
植物对氮（N）的吸收偏好是影响植物养分获取、植被组成和生态系统功能的关键因素。然而，很少有研究调查不同氮源对植物氮素策略的贡献，特别是在冰川退缩区的初级演替过程中。通过测量优势植物和土壤中氮同位素（δN）的自然丰度，我们估算了海螺沟冰川退缩区三个阶段（12年、40年和120年）的九种优势植物对不同氮形态（铵态氮-NH、硝态氮-NO和可溶性有机氮-DON）的相对贡献和吸收偏好。随着初级演替时间序列的推进，优势植物在早期（73.5%）和中期（46.5%）阶段更倾向于吸收硝态氮。在后期，土壤铵态氮的贡献超过60.0%。此外，可溶性有机氮对植物总氮吸收的贡献接近19.4%。因此，在初级演替过程中，优势植物在前两个阶段对硝态氮的偏好转变为后期对铵态氮的偏好。可溶性有机氮对优势植物氮源的贡献不容忽视。这表明优势植物氮吸收偏好的转变可能反映了其氮获取策略的调整，以响应其生理特征和土壤养分条件的变化。更好地了解植物对不同氮形态的偏好，能够显著增进我们对植物氮获取策略对环境变化潜在反馈的理解，并为不同演替阶段人工林的可持续管理提供有价值的建议。
