Photoblastic Germination Of An Invasive Species Of Eupatorium Adenophorum

Eupatorium adenophorum Spreng, which is perennial with woody rootstock and numerous upright branching stems, is one of the worst worldwide—spread invasive weed. To explore the impacts of this weed invasion on huge environmental catastrophe of our country, we systematically research on photoblastic germination of an invasive species of Eupatorium adenophorum. As the first step colonizing in a new habitat, seed germination and growth of seedlings should be related to its strong invasiveness. Combining experiments on different light intensity and different traditional dormancy-breaking treatments were carried out in this paper. We are aiming to answer two questions, i.e., whether or not germination of this weed is light-required, and how traditional dormancy-breaking methods and light intensity interactively affect germination and seedling growth. Next we have further specifically studied light quality and quantity influence on germination and seedling status of an invasive species, E. adenophorum.These findings found different color lights have significantly influence on parameters of seedling sprouting, such as, yellow light, orange light and etc, and these lights of the longer wavelength were more suitable for facilitating seed germination rate (74.3%～83.3%), while the shorter wavelength lights(<570nm, violet, blue and green light) had a significant lower seed germination (62.3%～66.7%)(p<0.05). Light intensity had markedly more regularity on seed germination and seedling status than the color of the light. Under the condition of darkness, germination percentage was22%. Along with the light enhancement in transmittaece, both germination and length of roots are increasing gradually. Appropriate radiation of red light (630nm) and far-infrared light (730nm) can break and cause dormancy. The exposure amount of red light linearly related with germination increase with reference to dark control (r2=0.98), while the amount of far-infrared light was linearly correlated with germination decrease with reference to control (r-=0.92). This indicates that light-demanding seed germination of E. adenophorum is a phytochromes-induced process.Our results may provide some meaningful advice for biological control. This species is much successful in sunny environment. Seed germination and seedling growth requires a certain amount of light. Therefore, we should make effective measures to reduce light intensity in the forest to prohibit high germination rate of the seeds of E.eupatorium. Besides, we can plan much plantations, especially mixed plantations so as to enhance far red, reducing the incidence of red light, which achieves the purpose of controlling, inhibiting its further spread of the population.