Responses of biomass allocation of Lagotis brachystachya to degradation ofsoil nutrition bank in alpine meadow

In order to understand responses of biomass allocation of Lagotis brachystachya to degradation of soil nutrition bank in highcold meadow, three plots with differences in nutritional composition of soil and in vegetable community characteristics caused by different utilizing methods of grassland were selected to investigate the biomass allocation of L. brachystachya in clonal plants in the source region of the Yangtze and Yellow Rivers. The results indicated that the biomass allocation of L. brachystachya to each clonal component was affected by soil nutrient resource heterogeneity obviously. L. brachystachya allocated more biomass to the roots of genet, while less biomass was gained in the leaves of genet and ramet under richer soil nutritional resource. The contrary trend was found under poorer soil nutrient resource. However, under moderate soil nutrient resource level, L. brachystachya tended to allocate the highest biomass to stolons, but the lowest in both richer and poorer soil nutrient condition. The pattern of biomass allocation varied with the change of soil nutrient resource, which was one of the ecological strategies that clonal plants exploited soil resource heterogeneous distribution effectively.