适应性的表型可塑性对外来植物入侵性的影响及其机制

The effects of phenotypic plasticity on invasiveness of introduced plant species are still not clear, while it is one of the earliest invasion theories. The problems in study methods of references may give a possible explanation for that. Plasticity in some traits may not be adaptive and can not facilitate invasion success of introduced plant species. To the best of our knowledge, however, no study has scientifically estimated the adaptive significance of functional traits when testing the relationships between plasticity and invasiveness. Furthermore, no effort has been made to consider the effects of resource availability and resource requirements of introduced species on the relationships between invasiveness and plasticity of functional traits. We will compare the differences in plastic responses to water and nutrient levels between six noxious invasive plant species and their phylogenetically related native species. Firstly, we will quantificationally estimate the adaptive significance of functional traits by phenotypic selection analysis. Then, we will explore the effects of adaptive and non-adaptive phenotypic plasticity on invasiveness of introduced plants and the underlying mechanisms, the effects of resource availability on adaptive significance of phenotypic plasticity and on the relationships between phenotypic plasticity and invasiveness of different alien plants that prefer to invade different habitats. We hypothesize that either higher or lower phenotypic plasticity can contribute to invasion success of alien plants, depending on trait itself, resource availability, and the resource requirements of target invasive plant. This is different with previous studies, which generally hypothesized that invasive plants have higher plasticity than natives. Our program may change people's idea about the relationships between plasticity and invasiveness, and stimulate related studies.

表型可塑性是最早提出的生物入侵机制之一，但至今其与外来植物入侵性的关系尚不明确，研究方法不当是重要原因。只有适应性的表型可塑性才可能促进外来植物入侵，但已有的研究并未考虑如何界定表型可塑性的适应意义，也忽视了环境资源水平和入侵种资源需求的影响。针对这些问题，本项目拟比较研究入侵不同生境的恶性外来入侵植物（3类6种）与本地近缘植物对土壤水分和养分可塑性响应的差异及其与入侵性的关系。通过表型选择分析，科学判断各性状表型可塑性的适应意义，据此，探讨适应性和非适应性的表型可塑性对外来植物入侵性的影响及其机制、资源水平对表型可塑性的适应意义的影响及对表型可塑性与不同类型外来植物入侵性关系的影响等。与以往研究不同，本项目假设高或低的表型可塑性均可能促进外来植物入侵，依性状本身、环境资源水平以及外来植物对资源的需求而定，这将改变人们对表型可塑性与入侵性关系的看法，促进相关研究工作的开展。

表型可塑性是最早提出的生物入侵机制之一，但至今其与外来植物入侵性的关系仍不明确。已有研究未考虑表型可塑性的适应意义、资源水平和入侵种资源需求对二者关系的影响。针对这些问题，项目比较研究了不同资源需求的外来入侵植物与同域本地近缘植物对5种养分和4种水分的可塑性响应的差异。我们首先通过表型选择分析，科学判断各性状表型可塑性的适应意义，之后探讨各功能性状可塑性的适应意义、环境资源水平和植物资源需求对可塑性与入侵性关系的影响。理论上，我们提出了研究表性可塑性与外来入侵植物入侵性关系的概念模型；探讨了3种常用的表型可塑性指标在相关研究中应用的可能性，证明反应规范斜率更实用。发现大部分功能性状的可塑性都是中性的，少数是适应性或非适应性的，因物种、性状及资源水平而异；用不同的适合度性状指标也影响功能性状可塑性的适应意义以及适合度可塑性与入侵性的关系；表型可塑性与外来植物入侵的关系依性状本身、环境资源水平以及外来植物对资源的需求而异。这将改变人们对可塑性与入侵性关系的看法，激发相关研究热情。项目共发表论文10篇，其中SCI论文8篇，累计影响因子32.965，单篇最高影响因子7.672；培养研究生7人。