Study on modular biomass dynamic changes of Leymus secalinus population in sexual reproductive stage

In this study，the dynamic changes and configuration pattern changes of modular biomass and rootshoot ratio of Leymus secalimus，a common grass in Yinchuan Plain were explored by field sampling and laboratory analysis. The results showed that the modular biomass and root-shoot ratio of L. secalimus population reflected the dynamic changes in sexual reproduction stage. The timely adjustment of biomass distribution reflected its investment allocation strategy，which continued for the species to survive and reproduce. In allocation pattern dynamics of the modular biomass，allocation ratio of stem biomass，flower and seed biomass showed inverted“ V” type variation；rhizome biomass（belowground biomass）accounted for a large configuration，reflecting“ V” type change；allocation ratio of leaf biomass reflected little change. In terms of the dynamic changes of modular biomass，leaf biomass had the volatility decline，stem biomass showed a single peak curve，monthly flower and seed biomass of allocation pattern showed inverted“V”type，rhizome biomass showed a slow downward trend，the change of total biomass also showed a downward trend，from June to September followed by 116.02 g/m2，105.66 g/m2，98.22 g/m2，73.23 g/m2. Root-shoot ratios were 1.1882，1.0461，0.7933，1.0742 from June to September，reflecting seasonal fluctuations. In June，the underground biomass was the maximum，root-shoot ratio also displayed the maximum. In August，the aboveground biomass was the maximum，root-shoot ratio shows the opposite result.