An integrated belowground trait-based understanding of nitrogen-driven plant diversity loss

作  者:Tian QY, Lu P, Zhai XF, Zhang RF, Zheng Y, Wang H, Nie B, Bai WM, Niu SL, Shi PL, Yang YH, Li KH, Yang DL, Stevens C*, Lambers H, Zhang WH*
影响因子:11.716
刊物名称:Global Change Biology
出版年份:2022
卷:  期:  页码:DOI: 10.1111/gcb.16147

论文摘要:

Belowground plant traits play important roles in plant diversity loss driven by atmospheric nitrogen (N) deposition. However, the way N enrichment shapes plant microhabitats by patterning belowground traits and finally determines aboveground responses is poorly understood. Here, we investigated the rhizosheath trait of 74 plant species in seven N-addition simulation experiments across multiple grassland ecosystems in China. We found that rhizosheath formation differed among plant functional groups and contributed to changes in plant community composition induced by N enrichment. Compared with forb species, grass and sedge species exhibited distinct rhizosheaths; moreover, grasses and sedges expanded their rhizosheaths with increasing N-addition rate which allowed them to colonize belowground habitats. Grasses also shaped a different microenvironment around their roots compared with forbs by affecting the physicochemical, biological, and stress-avoiding properties of their rhizosphere soil. Rhizosheaths act as a “biofilm-like shield” by the accumulation of protective compounds, carboxylic anions and polysaccharides, determined by both plants and microorganisms. This enhanced the tolerance of grasses and sedges to stresses induced by N enrichment. Conversely, forbs lacked the protective rhizosheaths which renders their roots sensitive to stresses induced by N enrichment, thus contributing to their disappearance under N-enriched conditions. This study uncovers the processes by which belowground facilitation and trait matching affect aboveground responses under conditions of N enrichment, which advances our mechanistic understanding of the contribution of competitive exclusion and environmental tolerance to plant diversity loss caused by N deposition.

全文链接:https://doi.org/10.1111/gcb.16147