甘肃省部分地区豆科植物根瘤菌资源调查

对甘肃庆阳、平凉、白银、兰州、临夏、定西、天水、甘南和陇南等地区的豆科植物及其共生根瘤菌资源进行了调查,共采集到豆科植物根瘤标本800多份,分别属于34属82种及变种,分离得到根瘤菌790余株;采集的根瘤形状以球形、棒形和掌形为主,部分呈现珊瑚形;根瘤颜色以土黄色、白色、浅褐色和粉红色为主,部分为红色或深褐色。研究发现,根瘤着生部位与寄主基因型有很大关系,调查的豆科植物中92．6％的根瘤着生在侧根上, 其余着生在主根或主侧根上;属内种间根瘤的形状、大小、颜色和着生部位相似,但是不同属间根瘤的形状、颜色、大小和着生部位存在明显差异;根瘤菌的分布与外界因素有密切联系,海拔、土壤水分和土壤肥力均会影响根瘤的分布和数量。在甘肃省大部分地区,豆科植物及其伴生植物在分布上也表现出一定的规律性,光线好、水分多的区域及阳坡、水渠边和路边均有大量豆科植物分布,伴生植物种类单一,以禾本科和菊科植物居多,但数量较少;同时发现,在调查地区,豆科植物被广泛用于防止水土流失和防止土壤沙漠化。

Investigation of leguminous plants and rhizobial resources in some areas of Gansu province

The nodulation and nitrogen-fixing resources of legumes plants from 31 counties of Gansu province were investigated ;meanwhile the corresponding rhizobia were isolated. The 31 counties belong to Qingyang, Pingliang, Baiyin, Lanzhou, Linxia, Dingxi, Tianshui, Gannan and Longnan. In total, 790 strains were isolated from 800 nodule samples ,whose hosts belong to 34 genera ,82 species or varieties. These nodules are mainly round,ellipse and eoralloid in shape,pink and yellow in color,with size ranging from 1 mm to 10 ram. The shape is determined by meristem,if it has meristem,it will be ellipse and eoralloid ;if not,it will be round. The color of the nodules are decided by legohomoglobin,whieh is very important in the process of nitrogen-fixing. It is found that the shape,size and color of nodules are similar among different species,which belong to the same genus,but there are great differences if these nodules belong to different genera. The color,shape and size are deeply affected by soil condition. In addition the relationship between the distribution of rhizobia and the natural factors is very close,namely soil moisture,soil temperature and elevation. To some extent ,the distribution of legumes and their associated plants show some principle ,the legumes almost live in the place with enough light, moisture and nutrition. The diversity of associated plants is relatively limited ,and the number is limited. Additionally ,it is found that many legumes are used in soil and water conservation,in preventing the soil from desertifieation.