Genetic Diversity of Stratiotes aloides L. (Hydrocharitaceae) Stands across Europe.

Barbara Turner,Karl-Georg Bernhardt,Andreas Hudler,Steffen Hameister

doi:10.3390/plants10050863

Abstract

Intense land use and river regulations have led to the destruction of wetland habitats in the past 150 years. One plant that is affected by the reduction in appropriate habitats is the macrophyte Stratiotes aloides which has become rare in several areas. The preservation of genetic diversity within a species is a prerequisite for survival under changing environmental conditions. To evaluate the level of genetic diversity within and among populations of Stratiotes aloides, we investigated samples from waterbodies across Europe using AFLP. Low genetic diversity among samples from the same population was found, proving that stands consist of few clones which propagate clonally. Nevertheless, most populations showed differences compared to other populations indicating that there is genetic diversity within the species. The analyzed samples formed two groups in STRUCTURE analyses. The two groups can be further subdivided and mainly follow the major river systems. For conserving the genetic diversity of Stratiotes aloides, it would thus be preferable to focus on conserving individuals from many different populations rather than conserving selected populations with a higher number of individuals per population. For reintroductions, samples from the same river system could serve as founder individuals.

Highlights

The monotypic genus Stratiotes includes the sole living species S. aloides L. and is a member of the Hydrocharitaceae which belong to the order Alismatales within monocots
In this study, we aim to investigate the genetic diversity of Stratiotes aloides populations across Europe to obtain insights into the circumference of the genepool of the species
In this study, we examined the genetic diversity of Stratiotes aloides populations from different water systems across Europe

Summary

Introduction

The monotypic genus Stratiotes includes the sole living species S. aloides L. (water soldier) and is a member of the Hydrocharitaceae which belong to the order Alismatales within monocots. During the Tertiary and Quaternary periods, there were up to twenty different species of the genus Stratiotes in Europe and Asia [1] (and references therein). During the vegetative and reproductive period of a year, the plants are mostly emergent with the rhizoids free in the water or loosely attached to the soil. The plant submerges in order to overwinter at the bottom of the water until the following spring [2]. Since vegetative reproduction is much more common in S. aloides, stands in one waterbody are often formed by clonal individuals of the same sex [2,3]. As long as individuals from different sexes are not transferred from one waterbody to another by floods and high waters, sexual reproduction is very rare. As a typical flood plain species, it inhabits slow-moving or stagnant waters such as ponds, canals, ditches and oxbow waters where it often dominates macrophyte communities [1]

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