Key Laboratory of Genetics and Germplasm Innovation of Tropical Special Forest Trees and Ornamental Plants, Ministry of Education, College of Forestry, Hainan University, Haikou, 570228, China.
State Key Laboratory of Biocontrol and School of Life Sciences, Sun Yat-Sen University, Guangzhou, 510275, China.
New Phytol. 2023 Apr;238(1):393-404. doi: 10.1111/nph.18737. Epub 2023 Feb 7.
Plant-soil feedbacks (PSFs) are an important mechanism of species coexistence in forest communities. However, evidence remains limited for how light availability regulates PSFs in species with different shade tolerance via changes in plant-microbial interactions. Here we tested in a glasshouse experiment how PSFs changed as a function of light availability and tree shade tolerance. Soil bacterial and fungal communities were profiled using the 16S rRNA and ITS2 gene sequencing, respectively. Under low light, individual PSFs were positively related to shade tolerance, while the least shade-tolerant species produced the most positive PSFs under high light. Pairwise PSFs between species with contrasting shade tolerance were strongly positive under high light but negative under low light, thereby promoting the dominance of less shade-tolerant species in forest gaps and species coexistence under closed canopy, respectively. Under high light, PSFs were related to soil microbial composition and diversity, with the relative abundance of arbuscular mycorrhizal fungi being the primary driver of PSFs. Under low light, none of soil microbial properties were significantly related to PSFs. These findings indicate PSFs and plant shade tolerance interact to promote species coexistence and improve our understanding of how soil microbes contribute to variation in PSFs.
植物-土壤反馈（PSFs）是森林群落中物种共存的一个重要机制。然而，关于光照可用性如何通过植物-微生物相互作用的变化来调节不同耐荫性物种的 PSFs 的证据仍然有限。在这里，我们通过温室实验测试了 PSFs 如何随光照可用性和树木耐荫性的变化而变化。分别使用 16S rRNA 和 ITS2 基因测序对土壤细菌和真菌群落进行了分析。在低光下，个体 PSFs 与耐荫性呈正相关，而在高光下最不耐荫的物种产生了最积极的 PSFs。在高光下，具有相反耐荫性的物种之间的成对 PSFs 呈强烈正相关，但在低光下呈负相关，从而分别促进了森林空隙中较少耐荫物种的优势和树冠闭合下的物种共存。在高光下，PSFs 与土壤微生物组成和多样性有关，丛枝菌根真菌的相对丰度是 PSFs 的主要驱动因素。在低光下，土壤微生物特性与 PSFs 均无显著相关性。这些发现表明 PSFs 和植物耐荫性相互作用，促进了物种共存，并提高了我们对土壤微生物如何促进 PSFs 变化的理解。
