Qin Fangcuo, Yu Shixiao
State Key Laboratory of Biocontrol, Department of Ecology, School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
Front Plant Sci. 2021 Feb 12;12:616726. doi: 10.3389/fpls.2021.616726. eCollection 2021.
Mixed-species forest plantation is a sound option to facilitate ecological restoration, plant diversity and ecosystem functions. Compatible species combinations are conducive to reconstruct plant communities that can persist at a low cost without further management and even develop into natural forest communities. However, our understanding of how the compatibility of mycorrhizal types mediates species coexistence is still limited, especially in a novel agroforestry system. Here, we assessed the effects of mycorrhizal association type on the survival and growth of native woody species in mixed-species plantations. To uncover how mycorrhizal type regulates plant-soil feedbacks, we first conducted a pot experiments by treating distinct mycorrhizal plants with soil microbes from their own or other mycorrhizal types. We then compared the growth response of arbuscular mycorrhizal plants and ectomycorrhizal plants to different soil microbial compositions associated with plants. We found that the type of mycorrhizal association had a significant impact on the survival and growth of native tree species in the plantations. The strength and direction of the plant-soil feedbacks of focal tree species depended on mycorrhizal type. Non-mycorrhizal plants had consistent negative feedbacks with the highest survival in the plantations, whereas nitrogen-fixing plants had consistent positive feedbacks and the lowest survival. Arbuscular mycorrhizal and ectomycorrhizal plants performed varied feedback responses to soil microbes from distinct mycorrhizal plant species. Non-mycorrhizal plants grew better with soil microbes while nitrogen-fixing plants grew worse with their own conspecific soil microbes. Different soil microbial compositions of consistently increased the aboveground growth of arbuscular mycorrhizal plants, but the non-mycorrhizal microbial composition of the soil resulted in greater belowground growth of ectomycorrhizal plants. Overall, plants induced an unfavorable soil community, impeding coexistence with other mycorrhizal plants. Our study provides consistent observational and experimental evidence that mycorrhizal-mediated plant-microbial feedback on species coexistence among woody species. These findings are with important implications to optimize the species combinations for better design of mixed forest plantations.
混交林种植是促进生态恢复、植物多样性和生态系统功能的合理选择。兼容的物种组合有利于重建植物群落，这些群落能够以低成本持续存在，无需进一步管理，甚至可以发展成天然森林群落。然而，我们对菌根类型的兼容性如何介导物种共存的理解仍然有限，尤其是在新型农林业系统中。在这里，我们评估了菌根关联类型对混交林中本地木本物种存活和生长的影响。为了揭示菌根类型如何调节植物-土壤反馈，我们首先通过用来自自身或其他菌根类型的土壤微生物处理不同的菌根植物进行了盆栽实验。然后，我们比较了丛枝菌根植物和外生菌根植物对与植物相关的不同土壤微生物组成的生长反应。我们发现菌根关联类型对种植园中本地树种的存活和生长有显著影响。焦点树种的植物-土壤反馈的强度和方向取决于菌根类型。非菌根植物具有一致的负反馈，在种植园中存活率最高，而固氮植物具有一致的正反馈且存活率最低。丛枝菌根和外生菌根植物对来自不同菌根植物物种的土壤微生物表现出不同的反馈反应。非菌根植物与土壤微生物一起生长得更好，而固氮植物与它们自己的同种土壤微生物一起生长得更差。不同的土壤微生物组成持续增加了丛枝菌根植物的地上生长，但土壤的非菌根微生物组成导致外生菌根植物的地下生长更大。总体而言，植物诱导了一个不利的土壤群落，阻碍了与其他菌根植物的共存。我们的研究提供了一致的观察和实验证据，证明菌根介导的植物-微生物反馈对木本物种间的物种共存有影响。这些发现对于优化物种组合以更好地设计混交林种植具有重要意义。
