Adaptive photosynthetic strategies of the invasive plant and its hybrid to a low-light environment.

In stressful environments, invasive plants acclimate more efficiently than native plants and hybridization mainly contributes to this process. We examined changes in the morphological characteristics, photosynthetic characteristics, and antioxidant capacity of and its hybrids in a low-light environment to explore their invasiveness, with serving as the control. The morphological plasticity of was not dominant, the maximal photochemical efficiency of PSII, actual quantum yield of PSII, and electron transport rate of PSII increased and nonphotochemical quenching decreased, while and the hybrid produced opposite results. showed fewer spots stained for reactive oxygen species in tissues, with an increase in superoxide dismutase activity. Although is a heliophilous plant, we found that the shade tolerance of and the hybrid were stronger than that of , which may be one important mechanism of invasion.