ABSTRACT

In defence against environmental constraints, plants respond by changing their morphology and/or physiology and this reaction can be a manifestation of a life strategy. Amphibious plants are good models to test for life strategies because they display plastic responses to aquatic and terrestrial conditions. In our study we investigated the architecture and phenotypic responses of the boreal plant Ranunculus reptans L. to water level changes by observing spontaneous aquatic populations during their flowering period and by conducting experimental transplantation. We interpret these data (1) in terms of adaptation to aquatic versus terrestrial conditions, and (2) as a manifestation of the life strategy. We document a radical change in R. reptans architecture and reproduction. Reduction of plant size, elongation of leaves and stolons, vegetative reproduction are characteristic of aquatic plants. Terrestrial plants are bigger, with wider lanceolate leaves and shorter stolons leading to higher density; they reproduce vegetatively and generatively. R. reptans appeared to follow the avoidance life strategy: (1) small growth form in aquatic conditions minimises the frontal area and diminishes the risk of uprooting; (2) elongated submerged leaves decrease hydraulic resistance and mechanical damages; (3) formation of individuals with multiple axes reduce the risk of uprooting by waves; (4) capacity to quickly reconfigure the architectural traits of aquatic and terrestrial plants adjusts them to changes in environmental conditions. Our findings thus suggest that R. reptans is phenotypically plastic and adjusts vegetatively to water level, essentially reflecting an avoidance strategy, while using complementarily terrestrial and aquatic conditions in its reproduction.

摘要

为了抵御环境限制，植物通过改变其形态和/或生理来作出反应，而这种反应可能是生命策略的体现。两栖植物是测试生命策略的好模型，因为它们对水生和陆地条件表现出可塑性响应。在我们的研究中，我们通过观察开花期自发水生种群并进行实验性移植，研究了北方植物毛an毛an的结构和表型对水位变化的反应。我们解释这些数据（1）适应水生和陆地条件，以及（2）作为生命策略的体现。我们记录了R. reptans的根本变化建筑与复制。减少植物的大小，叶片和茎的伸长，无性繁殖是水生植物的特征。陆生植物较大，披针形叶片较宽，茎较短，因此密度较高。它们无性繁殖和生殖繁殖。Reptans似乎遵循了回避生活策略：（1）在水生条件下小的生长形式使额叶面积最小化并减少了连根拔起的风险；（2）较长的浸没叶片降低了水力阻力和机械损伤；（3）组建多轴个人减少了因波浪连根拔起的风险；（4）快速重新配置水生和陆生植物的建筑特征的能力使其可以适应环境条件的变化。因此，我们的研究结果表明，瑞普雷氏菌在表型上是可塑性的，并且可以营养调节至水位，从根本上反映了一种避免策略，同时在繁殖过程中使用了陆生和水生条件。