School of Earth and Environmental Sciences, The University of Manchester, Oxford Road, Manchester, M13 9PT, UK.
Department of Botany, Institute of Ecology and Earth Sciences, University of Tartu, Lai 40, Tartu, 51005, Estonia.
New Phytol. 2017 Oct;216(1):90-98. doi: 10.1111/nph.14653. Epub 2017 Jun 13.
Plant genetic diversity can affect ecosystem functioning by enhancing productivity, litter decomposition and resistance to natural enemies. However, the mechanisms underlying these effects remain poorly understood. We hypothesized that genetic diversity may influence ecosystem processes by eliciting functional plasticity among individuals encountering kin or genetically diverse neighbourhoods. We used soil conditioned by groups of closely related (siblings) and diverse genotypes of Deschampsia cespitosa - a species known to exhibit kin recognition via root exudation - to investigate the consequences of kin interactions for root litter decomposition and negative feedback between plants and soil biota. Genetically diverse groups produced root litter that had higher nitrogen (N) content, decomposed faster and resulted in greater N uptake by the next generation of seedlings compared with litter produced by sibling groups. However, a similar degree of negative soil feedback on plant productivity was observed in soil conditioned by siblings and genetically diverse groups. This suggests that characteristics of roots produced by sibling groups slow down N cycling but moderate the expected negative impact of soil pathogens in low-diversity stands. These findings highlight interactions between neighbouring genotypes as an overlooked mechanism by which genetic diversity can affect biotic soil feedback and nutrient cycling.
植物遗传多样性可以通过提高生产力、凋落物分解和抵御天敌来影响生态系统功能。然而，这些影响的机制仍知之甚少。我们假设，遗传多样性可以通过在遇到亲缘或遗传多样性的个体中引发功能可塑性，从而影响生态系统过程。我们使用由亲缘关系密切的（兄弟姐妹）和多样性基因型的羊茅组成的群体产生的土壤来研究亲缘关系相互作用对根凋落物分解和植物与土壤生物群之间的负反馈的影响。与由兄弟姐妹群体产生的凋落物相比，遗传多样性群体产生的根凋落物具有更高的氮（N）含量，分解速度更快，导致下一代幼苗吸收更多的 N。然而，在由兄弟姐妹和遗传多样性群体产生的土壤中，观察到对植物生产力的类似程度的负土壤反馈。这表明，由兄弟姐妹群体产生的根的特征会减缓氮循环，但可以减轻在低多样性林分中土壤病原体的预期负面影响。这些发现强调了相邻基因型之间的相互作用是遗传多样性影响生物土壤反馈和养分循环的一个被忽视的机制。
