Studees On Appilication Of Symbionts In The Introduction And Cultivation Of The Endangered Ammopiptanthus Mongolicus

Thirty two soil samples from four field sites, where the endangered evergreen shrub Ammopiptanthus mongolicus resides in the desert region of north-west China, were collected and multiplied on Trifolium pratense under greenhouse condition for one or two cycle. Five kinds of arbuscular mycorrhiza fungi(AMF) spores with higher density were isolated from the multiplied soil sample of DengKou, one of the four study sites, by wet sieving method. The spores extracted were set up monospecific or mix culture in pot using sorghum as host to produce inoculum for further study. The nodule of A. mongolicus are greatly diversified in its shape and, from which 3 strains of rhizobia were isolated on the YAM plate.In the case of container seedling culture, to each pot add a mycorrhizal "inoculum" of one of three types: (l)soil around the roots system of A. mongolicus and its roots mixture collected from the sample field, (2)water filt of the former mixture, (3) the steam sterilized soil mixture. Seedlings of A. mongolicus were significantly increased in plant hight and stem diameter after inoculate with the(1) or (2) inoculum, but with no significant effect between them. It can be infered that once altering the nutrient environment of the indigenous AMF, which is well adapted to the nutrient poor soils of the arid desert region , does alter the mutualistic balance sheet. Another reason for this phenomenon is that the AM propagules in the soil are inadequate for the colonization of the fungi to set up a mutulistic relationship that mostly benefits the host.At the same time, four speices of AM fungi in the genera of Glomus obtained from the Research Institute of Agriculture and Forest Science of Beijing were used in container seedling culture procedure. Results show that the growth of A. mongolicus were significantly enhanced after inoculated with the G. mosseae or G. versiforme compared with the uninoculated, while the G. etunicatum or G. diaphanum were not showing significant effect. Therefore, for the relatively fertile soil, the AM fungi species frequently used in agriculture and horticulture might gain more reasonable result than the native AM fungi.Further, in order to introduce this shrub with beautiful flower to the gardens of north China, this thesis also deals with the cultivation techniques and maintenance of A. mongolicus in Beijing where the precipitation were three times more than its habitat.