Seed Biological Characteristics And Rhizosphere Nitrogen Distribution Of Several Leguminous Plants

Wild legume resources in Qinghai province were investigated to elaborate on their distribution.The seed dormancy of 10 leguminous species,Vicia cracca L,Vicia sativa L,Melilotus albus Desr,Melilotus officinalis L,Trifolium hybridum L,Trifolium glanduliferum Boiss,Medicago sativa L,Tibetania himalaica Baker,Lotus corniculatus L,Lupineus micranthus Guss,were analyzed by morphology characters of seed and seed coat,anatomical structure of seed coat and a seed germination test.Important reference could be provided for the feasibility of introducing such leguminous plants in alpine regions by cultivation experiments.The vertical and horizontal distribution of soil nitrogen in rhizosphere of 4 wild leguminous species were analyzed to initially obtain their regularities.The experimental results were as follows:(1)There were 19 genera and 187 species of wild leguminous plants in Qinghai Province.Few of them were forage legume plants which mainly distributed below the altitude of 3500 miters.Both of the forage legume plants' height and their aboveground biomass were low.(2)The hard seeds rate of Vicia cracca L,Melilotus albus Desr,Melilotus officinalis L,Tibetia himalaica Baker and Lupinus micranthus Guss was very high.And all of their hard seeds rate was more than 88%.In addition to the cultivated species of Lupinus micranthus Guss' s hard seed rate was 94%,the hardness of cultivated species was generally lower than that of wild species.The seed germination of 10 leguminous plants was not uniform.(3)In addition to Vicia sativa L and Lotus corniculatus L,the other 8 kinds of leguminous plants generally had seed cuticle,palisade layer,stone columnar cell layer and spongy tissue cells of the 4 layer cell structure.The hard rate was not only related to the composition of cell layer,but also with the thickness and the degree of compactness of each cell layer.Cuticle,palisade layer and columnar cell layer might be the main reason for the formation of hard seeds.(4)In the 10 species of leguminous plants who were planted in Henan county,three kinds of New Zealand plants(Trifolium hybridum L,Trifolium glanduliferum Boiss and Lotus corniculatus L)could not adapt the Henan county's climate,and their growth performance was poor.But Lupinus micranthus Guss which was originated from New Zealand had a good growth performance.And the same to 5kinds of plants who originate from Qinghai province.(5)There was no significant increase in nitrogen content in rhizosphere soil of4 wild leguminous plants in Henan county and Zeku county.The nitrogen content of rhizosphere soil of Oxytropis ochrocephala Bunge was relatively stable.Nitrogen content of Oxytropis coerulea(pall)DC decreased significantly at the 5 centimeter to 15 centimeter.The change range of rhizosphere soil nitrogen content around the root of Melilotoides archiducis-nicolai Sirj was small.The Tibetia himalaica Baker's root from 0 to 15 centimeter could improve the nitrogen content of rhizosphere soil.