Support from mother ramets declines with increasing independence of daughter ramets in submerged clonal Vallisneria natans

Abstract

Many aquatic plants are characterized by clonal growth through which the mother ramet can support offspring ramets by providing resources. The capacities of exploring space, sampling environment and overcoming establishment risks for offspring ramets could be enhanced with the resource support of the mother plant, which may change over time. This study aimed to investigate whether there is a change of clonal integration between mother ramets and offspring ramets in the submerged macrophyte Vallisneria natans with growth time. The stolons between mother ramets and daughter ramets were severed or intact at different growth times (7th day, 17th day, or 27th day after planting). The anatomical structure of the stolons and the morphological, biomass and nitrogen traits of the plants were measured. The results showed that the anatomical structure of the stolon changed significantly over time. The growth and clonal reproduction of daughter ramets were markedly improved by clonal integration on the 14th day but not on the 24th day or 34th day. In addition, there was no significant cost to support daughter ramets in terms of the total biomass of mother ramets. Our results highlight that the growth and clonal reproduction of daughter ramets of V. natans relies on mother ramets in the early stage and support from mother ramets declines with increasing independence of daughter ramets.