Abstract:Being native to Central and South America,Mikania micrantha H.B.K is a perennial herb or semi woody vine of Compositae.This plant has been considered one of the worst noxious weeds around the world and caused huge economic losses,serious ecological problems and biodiversity losses.The vegetative growth and reproduction is one of the most important reproduction strategies of M.micrantha.In this trial,the vegetative reproduction and biomass allocation characteristics of M.micrantha with two factor experiments of different growth periods (40 d,30 d,20 d and 10 d) and nutrient solutions (1 Hoagland’s,water+soil and water) were studied.The results showed that:(1)The growth period and nutrient had significant effect on stem survival rate and stem net biomass percentage of M.micrantha,respectively,but no significant effects of other indicators.Except the interaction between growth period and nutrient had no obvious impacts on root survival rate and stem branch number of M.micrantha,it had obvious effects of other indicators.(2)The survival rate of M.micrantha root in all treatments was 0 and the branch number of M.micrantha stem was not significantly different in all treatments.（3）The survival rate,biomass and branch length of M.micrantha stem were increased with increase in growth period and nutrient,and similarly survival rate,biomass,branch length,and branch number of M.micrantha leaf were improved too.However,the medium nutrient was more favorably increased survival rate,branch length,branch number,and biomass of M.micrantha leaf with shorter growth period than those with longer growth period.All these shows that the vegetative organs of M.micrantha have various survival rate,morphological plasticity and biomass allocation in different growth periods and nutrient solutions.