The Relationship Between Algal Crust And Seed Plants In Songnen Grassland

Songnen grassland is one of the important areas of animal husbandry development in our country,influenced by human disturbance in recent years,grassland degradation is becoming more and more serious.In Songnen grassland widely distributed algae crust, it has attracted much attention because of its important ecological functions.We chose Leymus chinensis community,Puccinellia tenuiflora community,Chloris virgata community,Artemisia anethifolia community,Suaeda corniculata community,the algal crusts lived under the plant community and the algal crust lived in Alkali spots for the experiment.Focuses on seed plants’ influence on cyanobacteria species composition of algal crusts,and algal crusts’ influence on seed plants settlement and growth,and explore its mechanism.Includes the following several aspects:the cyanobacteria species composition identification of algal crusts from different plant community types in Songnen Leymus chinensis grassland;Through field investigation and indoor simulation to study algal crust effect on seed plants’ settlement and growth;Algal crust aqueous extracts’ effects on seed plants germination.The study results show that:there are 34 species of cyanobacteria belong to 11 genera and 8 families in total from different plant community types.Microcoleus vaginatus is widely distributed and dominant species.The species composition in different environments are varying;Natural conditions,the exist of algal crusts depress perennials’ settlement like Leymus chinensis and Puccinellia tenuiflora,promote annuals’ settlement like Chloris virgata, Artemisia anethifolia and Suaeda corniculata.To analyze the reason is crusts influence soil surface’s ability to capture the seeds.The exist of algal crusts increase soil nutrients and promote seed plants’ growth;The simulation experiment results show that the exist of algal crusts depress seed plants emergence,promote plants’ height and photosynthetic pigment content and single plant’s biomass;The impact of algal crusts’ aqueous extracts from different plant community types on different seed plants’ germination rate is varying.Most of algal crusts’ aqueous extracts promote seed plants’ height(except Suaeda corniculata) and single plant’s biomass(except Puccinellia tenuiflora and Chloris virgata).The study discuss the relationship between algal crusts and seed plants in Songnen grassland,has theoretical significance on algal crust ecological function of grassland ecosystems.