Strategies of resource sharing in clonal plants: A conceptual model and an example of contrasting strategies in two closely related species

Abstract

Background and AimsClonal growth helps plants to cope with environmental heterogeneity through resource integration via connecting organs. Such integration is considered to balance heterogeneity by the translocation of resources from rich to poor patches. However, such an ‘equalisation’ strategy is only one of several possible strategies, as we discuss in a brief conceptual analysis. Under certain conditions, a strategy emphasising acropetal movement and exploration of new areas or a strategy accumulating resources in older ramets may be preferred. The optimal strategy may be determined by environmental conditions, such as resource availability and level of light competition. Therefore, species from different habitats may exhibit distinct resource translocation strategies.MethodsResource translocation was compared between two closely related species from different habitats with contrasting productivity. The study examined the bidirectional translocation of carbon and nitrogen in pairs of mother and daughter ramets grown under light heterogeneity (one ramet shaded) at two developmental stages using stable-isotope labelling.Key resultsAt the early developmental stage, both species translocated resources toward daughters and the translocation was modified by shading. Later, the species of low-productivity habitats,Fragaria viridis, translocated carbon to shaded ramets, according to the ‘equalisation’ strategy. The species of high-productivity habitats,Potentilla reptans, did not support shaded older ramets. Nitrogen translocation remained mainly acropetal in both species. These findings confirmed our expectations.ConclusionsThe two studied species exhibited different translocation strategies, which may be linked to the habitat conditions experienced by each species. The ‘equalisation’ strategy may occur in habitats with lower productivity and lower light competition, than the strategy emphasising acropetal movement. The results indicate that we need to consider different possible strategies. We emphasise the importance of bidirectional tracing in translocation studies and the need for further studies to investigate the translocation patterns in species from contrasting habitats.