Allelopathic effect of aqueous extract from Galinsoga parviflora on seedling growth and photosynthesis of Vicia faba.
To explore the effect of Galinsoga parviflora Cav., an invasive plant on seedling growth and photosynthetic physiological characteristics of broad bean (Vicia faba L.), the pot experiments were conducted to study the effects of plant heights, leaf areas, biomass, chlorophyll contents, chlorophyll fluorescence parameters and gas exchange parameters of broad bean seedlings. The resulta showed that, after treating with the aqueous extracts of G. parviflora, the results showed that leaf areas had little change, and the plant heights and the biomass were dramatically inhibited by the aqueous extracts in a time-dependent but not concentration-dependent manner. And net photosynthetic rate (Pn) were decreased markedly (P<0.05). The chlorophyll contents, chlorophyll fluorescence parameters (ΦPs II and Fv/Fm) and transpiration rates (Tr) were not inhibited by the aqueous extracts of G. parviflora significantly (P>0.05). These results suggested that the aqueous extracts of G. parviflora inhibited the growth of recipient plants by inhibiting the ability of assimilation of CO2 and reducing the biomass.