Why are some invasive plant species so successful in nutrient‐impoverished habitats in south‐western Australia: A perspective based on their phosphorus‐acquisition strategies

• Published in: Functional ecology Vol. 39; no. 2; pp. 635 - 652
• Main Authors: Tang, Dan, Yan, Li, Fisher, Judith L., Kang, Haibin, Dallongeville, Paul, Wasaki, Jun, Wang, Xiao, Lambers, Hans
• Format: Journal Article
• Language: English
• Published: London Wiley Subscription Services, Inc 01.02.2025
• Subjects: Arbuscular mycorrhizas; Australia; Biodiversity; Biodiversity hot spots; Biological invasions; Carboxylates; Exudation; Field investigations; Flowers & plants; Greenhouses; Hydroponics; Indigenous plants; Indigenous species; Introduced species; Invasive plants; Invasive species; leaf manganese; Leaves; Manganese; mycorrhiza; Nonnative species; Phosphorus; phosphorus acquisition; photosynthesis; photosynthetic phosphorus‐use efficiency; Plant species; Plants (botany); root carboxylate exudation; soil; species; vesicular arbuscular mycorrhizae; Australia
• ISSN: 0269-8463; 1365-2435
• DOI: 10.1111/1365-2435.14726

Invasive plants are a major cause of the global biodiversity crisis; it is therefore crucial to understand mechanisms that contribute to their success. South‐western Australia is a global biodiversity hotspot with extremely low soil phosphorus (P) concentrations. In this region, a large proportion of native plant species release carboxylates that mobilise soil P. Many widespread invasive plant species in south‐western Australia are arbuscular mycorrhizal (AM). We hypothesised that some of these invasive AM plant species exhibit similar P‐acquisition strategies as native carboxylate‐releasing P‐mobilising species which allows them to thrive in P‐impoverished soils. To test this hypothesis, we collected 23 common invasive species in the field and assessed their leaf manganese concentration [Mn], relative to that of native reference species at different locations, as a proxy for carboxylate release. In addition, we cultivated seven of the invasive species in hydroponics at different P supply to measure their root carboxylate exudation. Furthermore, we measured leaf P concentration and photosynthetic P‐use efficiency (PPUE) of five invasive species in the glasshouse. In the field investigation, almost all invasive species exhibited significantly higher leaf [Mn] than the negative references, which do not release carboxylates, indicating carboxylate release of the invasive plants. Leaf [Mn] of a few invasives even exceeded that of positive references, which exhibit significant carboxylate release, indicating substantial carboxylate release of these invasives. All glasshouse‐grown invasive species with high field leaf [Mn] released root carboxylates under low P supply. Most of the tested invasive plant species also exhibited greater PPUE than native plants under low P supply. Invasive AM plant species exhibited root exudation of carboxylates as a P‐acquisition strategy, which very likely allows their successful invasion of severely P‐impoverished habitats. Read the free Plain Language Summary for this article on the Journal blog. 摘要 入侵植物是造成全球生物多样性危机的一个主要原因。因此，了解其成功入侵的机制至关重要。澳大利亚西南部是全球生物多样性热点地区，并且土壤磷有效性极低。在这里，很大一部分本土植物通过释放根系羧酸盐来获取土壤中的磷；与此同时，许多广泛分布的入侵植物都具有丛枝菌根共生(AM)。我们推测，其中一些入侵的AM植物表现出与本土物种类似的磷获取策略，而这使它们能够在磷贫瘠的土壤中生长良好。 为了验证这一假设，我们在野外采集了23种常见入侵植物，评估了它们的叶片锰浓度[Mn]，并将其与不同地点的本土参考物种叶片[Mn]相对比，作为判断羧酸盐释放的指标。此外，我们在水培实验中以不同的磷供应量培养了七种入侵植物，以测量它们根部的羧酸盐释放。此外，我们还在温室中测定了五种入侵植物的叶片磷浓度和光合磷利用效率(PPUE)。 在野外调查中，几乎所有入侵植物的叶片[Mn]都明显高于不释放羧酸盐的阴性参照物，表明入侵植物释放了羧酸盐。部分入侵植物的叶片[Mn]甚至超过了有大量羧酸盐释放的阳性参照物，表明这些入侵植物有大量的羧酸盐释放。在低磷条件下，所有温室种植的入侵物种都释放了根系羧酸盐，这与它们野外叶片的高[Mn]相一致。在低磷条件下，大多数受测入侵植物的PPUE也高于本土植物。 入侵的菌根共生植物表现出释放根系羧酸盐来获取磷的策略，这促使它们能够成功入侵磷严重缺乏的生境。 Read the free Plain Language Summary for this article on the Journal blog.