Phenotypic plasticity affords invasive plant species the ability to
colonize a wide range of habitats, but physiological plasticity of their
stems is seldom recognized. Investigation of the stem plasticity of
invasive plant species could lead to a better understanding of their
invasiveness. We performed a pot experiment involving defoliation
treatments and an isolated culture experiment to determine whether the
invasive species Mikania micrantha exhibits greater plasticity in the
stems than do three native species that co-occur in southern China and
then explored the mechanism underlying the modification of its stem
photosynthesis. Our results showed that the stems of M. micrantha
exhibited higher plasticity in terms of either net or gross
photosynthesis in response to the defoliation treatment. These effects
were positively related to an increased stem elongation rate. The
enhancement of stem photosynthesis in M. micrantha resulted from the
comprehensive action involving increases in the Chl a/b ratio, D1
protein and stomatal aperture, changes in chloroplast morphology and a
decrease in anthocyanins. Increased plasticity of stem photosynthesis
may improve the survival of M. micrantha under harsh conditions and
allow it to rapidly recover from defoliation injuries. Our results
highlight that phenotypic plasticity promotes the invasion success of
alien plant invaders.
Stem photosynthesis: new evidence highlights the contribution of phenotypic plasticity to the invasion success of Mikania micrantha
