Small islands of safety promote the performance of a clonal plant in cadmium-contaminated soil

AimsSmall islands of safety, accompanied by clonal integration, could have important impacts on plant performance in stressful environments. Although the effects of environmental heterogeneity and clonal integration on clonal plant growth have been well studied, little attention has been paid to the impacts of islands of safety and the interaction with clonal integration on plant performance in the context of soil contamination.MethodsWe conducted an experiment consisting of two soil treatments (with/without an island of safety, i.e., a patch with uncontaminated soil, located in the middle of cadmium-contaminated soil) and two stolon connection statuses (stolon between the mother ramets and their daughter ramets was either severed or kept connected) using the stoloniferous clonal plant Glechoma longituba.ResultsOverall, the presence of the safe island significantly increased the number of ramets, total mass, leaf mass, and stolon mass of the daughter ramets and the whole clone. Clonal integration significantly decreased the number of ramets, total mass, leaf mass, and stolon mass of mother ramets. The presence of the island of safety enhanced total mass, leaf mass, and stolon mass of the mother ramet in the group with severed stolons and root mass and root to shoot ratio in the group with connected stolons.ConclusionsBuilding islands of safety can contribute to daughter ramet growth in a contaminated ecosystem, which suggests assembling smaller safe islands coupled with clonal plants with strong clonal integration may be a promising measure to vegetation restoration in heavy metal contaminated ecosystem.

Automated summary

This study found that establishing small islands of safety in contaminated soil can greatly enhance plant growth performance, especially for clonal plants. The presence of safe islands increased the number of branches and total mass of clonal plants, and promoted the growth of mother plants.