Abstract:The biomass of root, stem, leaf and flower, as well as the relationship of biomass allocation were studied from 60 flowering plants of Aster subulatus Michx. in the field. The results showed that the module biomass of A. subulatus was decreased in the order of stem>flower>root>leaf at flowering stage. Their variation coefficient was 57.15%, 64.66%, 57.65%, and 55.2%, respectively, which exhibited high phenotypic plasticity. The variation coefficient of biomass ratio was higher in flower than in other organs, which showed that this weed had high ability to adjusting reproduction allocation. Plant height had significant positive correlation with each module biomass and increased in the power function with the latter increment. Biomass allocation of flower had significant positive correlation with total biomass, but did not that of other organs. The biomass allocation was transferred from nutrition module, supporting module and photosynthesis module to reproduction module. In summary, A. subulatus had better assignment strategy for resource and stronger adaptive ability to heterogeneous environment.