Morphological plasticity of corms in enhancing invasion of Chromolaena odorata

In this paper, the researchers investigate the vegetative growth of Chromolaena odorata and the infl uence of light intensity on the understorey environment of Shorea robusta forest at Chitwan in south-central Terai, Nepal. C. odorata is a clonally growing shrub and typically consists of several clones with an underground “cormous organ” (a modifi ed stem to store food reserve; here after “corm”) belonging to an identical genet. In C. odorata, the biomass of such corms varied across the light gradient. The number of shoot demonstrated a strong logarithmic relation with biomass of corm. Under open forest canopy environment, corm biomass was strongly correlated with the number of shoots and the corm’s age. However, under dense forest canopy, there was no signifi cant relationship between corm biomass and its age. This result shows that corms of C. odorata were capable of maintaining their viability for a long period even under closed canopy environment. Any disturbances in forest canopy density would ultimately trigger its clonal growth capability. This plasticity of corms appeared to be a key strategy for invasion success of this species. Comparison of these results further indicates the importance of canopy density in determining invasion success of C. odorata.