Abstract

Aims

Global changes such as atmospheric CO₂ enrichment often facilitate exotic plant invasions and alter soil arbuscular mycorrhizal fungi (AMF) community. However, it is still unclear whether the effects of CO₂ enrichment on exotic plant invasions are associated with its effects on root-AMF symbiosis of invasive and native plants.

Methods

To address this issue, the annual invasive plant Xanthium strumarium and two phylogenetically related annual natives were compared under ambient and elevated CO₂ concentrations for three consecutive years.

Important Findings

Atmospheric CO₂ enrichment increased AMF colonization rates for the species only in few cases, and the invader did not benefit more from CO₂ enrichment in terms of AMF colonization. Under ambient CO₂ concentration, however, the invader had a higher AMF colonization rate than the natives in the first year of the study, which disappeared in the second and third year of the study due to the increase of AMF colonization rates in the natives but not in the invader. The influences of species, CO₂ concentrations and planting year on AMF colonization were associated with their effects on both soil nutrient and AMF community, and the former may be more important as it also influenced the latter. Our results indicate that the invader could more quickly form symbiosis with soil AMF, contributing to adaptation and occupation of new habitats, and that it is necessary to consider the roles of AMF and the effects of time when determining the effects of global changes such as atmospheric CO₂ enrichment on exotic plant invasions.

中文翻译：

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在不同二氧化碳浓度下生长三年的温带入侵者和共生本地人的 AMF 定植和群落

摘要

宗旨

大气 CO ₂富集等全球变化通常会促进外来植物入侵并改变土壤丛枝菌根真菌 (AMF) 群落。然而，目前尚不清楚CO ₂富集对外来植物入侵的影响是否与其对入侵植物和本地植物根-AMF共生的影响有关。

方法

为了解决这个问题，连续三年在环境和升高的 CO ₂浓度下对一年生入侵植物 Xanthium strumarium 和两个系统发育相关的一年生本地植物进行了比较。

重要发现

大气 CO ₂富集仅在少数情况下增加了该物种的 AMF 定植率，并且入侵者在 AMF 定植方面并未从 CO ₂富集中获益更多。然而，在环境 CO ₂浓度下，入侵者在研究的第一年具有比本地人更高的 AMF 定植率，在研究的第二年和第三年由于本地人 AMF 定植率的增加而消失，但不在入侵者中。物种的影响，CO ₂AMF 定植的浓度和种植年份与其对土壤养分和 AMF 群落的影响有关，前者可能更重要，因为它也影响了后者。我们的结果表明，入侵者可以更快地与土壤 AMF 形成共生关系，有助于适应和占领新的栖息地，并且在确定大气等全球变化的影响时，有必要考虑 AMF 的作用和时间的影响。 CO ₂富集对外来植物入侵。