Temporal coupling of plant and microbial nitrogen uptake and plant nitrogen reallocation improve grassland nitrogen retention under nitrogen addition

文献类型： 外文期刊

第一作者： Gong, Jirui

作者： Gong, Jirui;Zhang, Siqi;Zhang, Weiyuan;Dong, Jiaojiao;Dong, Xuede;Liu, Yingying;Wang, Biao;Zhang, Zihe;Song, Liangyuan;Yan, Yuchun

作者机构：

关键词： Nitrogen addition; N-15 labeling; Nitrogen partitioning; Semi-arid temperate steppe; Plants-microbial nitrogen competition; Nitrogen reallocation

期刊名称：JOURNAL OF ARID ENVIRONMENTS （ 影响因子：2.6； 五年影响因子：2.6 ）

ISSN： 0140-1963

年卷期： 2024 年 224 卷

页码：

收录情况： SCI

摘要： Efficient nitrogen (N) acquisition by plants and microbes and internal reallocation of plant N are crucial for improving ecosystem N retention. However, little is known about shifts in N use strategy between plants and microbes under N addition. We used a(15)N tracer to investigate effect of N addition (0-25 g N m(-2) yr(-1)) on the N use and retention of plant-microbe-soil system in a temperate Chinese steppe. Adding 2-5 g N m(-2) yr(-1) increased the ecosystem's ability to retain 15N (65-76%) after 1 year. Plant N demand during the peak growth period depended strongly on rapid N immobilization by microbes during 7 days (immobilized 45% of N-15 within 24 h). When root biomass exceeded 0.36 kg m(-2), plants competed more strongly for N than the microbes. N addition increased N reallocation from roots to support new shoot growth (79-88% of N), because increased shoot N demand triggered root N transfer when external N was supplied. Thus, the temporal coupling between plant and microbial N use and in N reallocation within plants significantly altered the semi-arid grassland N cycle, and better predicting impacts of future N deposition scenarios.

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