Clonal fragments of stoloniferous invasive plants benefit more from stolon storage than their congeneric native species

Abstract

Plants with clonal growth may suffer from great fragmentation risk due to frequent disturbance. Meanwhile, storage capacity of clonal organs (stolon or rhizome) is important for survival and growth of clonal fragments. However, few studies have compared the difference in the regeneration capacity of clonal fragments between invasive clonal plants and congeneric native species. More studies between invasive plants and their congeneric native species are needed to provide insight into traits that contribute to invasiveness. Single-node fragments with stolon internode of different length were used to investigate the effects of stolon storage on survival and growth of three stoloniferous invasive plants (Wedelia trilobata, Alternanthera philoxeroides and Hydrocotyle vulgaris) and their congeneric native species (Wedelia chinensis, Alternanthera sessilis and Hydrocotyle sibthorpioides). Soluble sugar, starch and soluble protein contents of stolon internode per unit length were significantly greater in the three invasive plants than in their congeneric native species. During the experiment, regeneration of clonal fragments was not observed in A. sessilis. With increasing of stolon internode length, accumulative emergence rate of clonal fragments and biomass of their regenerated ramets significantly increased in the other five species. Accumulative emergence rate of clonal fragments and biomass of their regenerated ramets were significantly greater in invasive plant H. vulgaris than in its congeneric native species. A similar pattern was observed in the clonal fragments with stolon internode of long and medium length for Wedelia species pair. In the experiment, regeneration capacity of clonal fragments varied with species and stolon internode length. Clonal fragments of stoloniferous invasive plants benefit more from stolon storage than their congeneric native species. It is suggested that clonal storage may be an important trait for invasiveness of stoloniferous invasive plants. Therefore, intentional fragmentation should be carefully employed to manage stoloniferous invasive plants and avoid the dispersal of generative clonal fragments.