根瘤菌

All the results suggested that peanut isolates are all belong to biovars of B. japonicum. They are designed as B. japonicum bivar arachis and B. japonicum bivar arachis .

由于供试花生根瘤菌与大豆慢生根瘤菌的参比菌株具有较高的遗传相似性，作者建议将供试根瘤菌分类地位的范围定为大豆慢生根瘤菌花生生物型Ⅰ和花生生物型Ⅱ。

To better understand the roles of LsrA protein in nodulation, a series of analyses of nodules using scanning electron microscopy, genetic and biochemical approaches have been carried out. Our analyses suggest that the lsrA1 nodules contain bacteroids in the invasion and establishing zone only. The lsrA gene expression is active early in the invasion zone and activated later than bacA genes. The lost of LsrA protein dramatically reduced the expression of nifA and fixK, and completely blocked the expression of the nifH gene for nitrogenase. LsrA protein functions early in the bacteroid development and it is essential for the development nitrogen fixing bacteroids.

前期的工作中，苜蓿中华根瘤菌Rm1021中90个候选LysR基因已经被定向插入突变，并筛选在自生生长时期、共生生长时期的表型，以期寻找更多在自生状态或共生固氮中有功能的LysR转录因子。1 针对前期鉴定出的共生固氮必需的lsrA基因，我们应用了一系列扫描电子显微镜技术、生物化学、分子遗传学等方法，发现lsrA基因主要在根瘤侵染区开始表达，表达时序也在侵染阶段左右，但晚于bacA基因表达；LsrA蛋白缺失后根瘤固氮区中缺乏具有固氮能力的类菌体，nifA和fixK基因的转录水平降低，nifH基因的转录被完全阻断，因此LsrA蛋白为根瘤发育所必需，是新的根瘤发育信号传导途径成员。2 通过表型筛选我们鉴定了苜蓿中华根瘤菌的oxyR基因，并研究了它的调节特性。oxyR突变后，苜蓿中华根瘤菌对过氧化氢敏感性提高，适应性降低。

In comparison,the rhizobia in mature infected cells were larger,greater in number,varied in shape,and distributed throughout the nodule cells.The rhizobia in the mature cells also had poly-hydroxy butanoic acid and curapos.

成熟侵染细胞中，根瘤菌个体较大，数量较多，多呈棒状，少数为球形或椭球形，有很多根瘤菌还呈现明显的"T"形、"Y"形或"V"形，菌体占满了整个细胞，这时的根瘤菌大多数含有聚羟基丁酸和聚磷酸盐颗粒。

The occurrences, relative abundance, relative density, most common and longest SSRs in the three species were analyzed and compared with each other. The results revealed that the SSRs number in B. japonicum, M. loti and S. meliloti genomes were 1410, 859 and 638, respectively. In the three genomes, tetra-, penta-and hexa-nucleotide repeats were more abundant, indicating higher mutation rates in these species.

大豆慢生根瘤菌、百脉根根瘤菌和苜蓿中华根瘤菌基因组中的SSRs分别为1410个、859个和638个，3种根瘤菌基因组中长重复的四、五、六核苷酸基序更为丰富，变异性更高。

Host plant could also influence the competitiveness of rhizobia which shown the interaction between rhizobium and plant.

同时，宿主植物对根瘤菌的竞争结瘤也有着明显的影响。在偏酸的条件下，慢生根瘤菌的生长状况较好竞争结瘤能力强而在偏碱的条件下，快生根瘤菌的竞争能力强。

With the found of new Rhizobium resources and development of science and technology,Rhizobium taxonomy has transfer from tradition classification to modern systematic taxonomy.

随着根瘤菌资源的不断发现和科学技术的不断发展，根瘤菌分类从以互接种族为依据的传统分类逐步过渡到了以系统发育关系为依据的现代系统分类，特别是近十几年来，生物技术应用于根瘤菌系统发育及其分类的研究进一步促进了根瘤菌资源的开发利用，使得根瘤菌的分类及其系统发育研究有了突破性进展。

Discussed the subject on the rich symbiont germplasm resource in China and on further research being necessary to exploitation and utilization of the benificial germplasm.

文摘：针对我国主要豆科作物大豆和花生的研究成果，并结合本身研究工作内容，(1)总结了与宿主共生的根瘤菌生物学多样性，包括大、小样本的土著根瘤菌群体数量、分离频率、类型与分布及其菌株―宿主共生混交性与亲和性；(2)评述了根瘤菌―宿主植物共生体双边固氮改良，包括优良菌株的选育、宿主品种资源共生特性的评价与利用及特异性状的选择；(3)讨论了我国这一类共生体资源的丰富性以及有必要进一步加大力度研究有益资源的开发和利用的问题。

Temporally, rhizobium abundance in root and pericarp is obviously higher at pod-bearing stage than any other growth stage. Rhizobium abundance in various floral organs rapidly increases after pollination. During ovary-to-legume germinative process, rhizobium abundance in ovary wall and ovule increases logarithmically. Endogenous rhizobia are found in ovule only after fertilization, and rhizobium abundance in young seeds is higher than in fertilized ovule. This implies that endogenous rhizobia can be transported and colonized in early germinated seedlings.

在时间上，结荚期根、荚果皮内的根瘤菌数量明显高于其他时期；花内各器官在授粉后根瘤菌数量迅速增加；由子房向荚果发育的过程中，子房壁和胚珠内的根瘤菌数量随时间呈对数增长；胚珠在受精后即存在有内生根瘤菌，并且幼嫩种子内生根瘤菌数量远高于受精胚珠，证明内生根瘤菌能被转运并定殖在发育早期的种子中。

Furthermore, there is a great phenotypic diversity among the new strains isolated from the same host. Different groups consisted of the new strains from the same host, some were Rhizobium, some were Bradyrhizobium, such as the new strains isolated from leguminous plants of AMkora Prain, Trifolium repens Lam, Aeachynomene Mica L, Indigofera bungeana Steud.

同时，攀西地区豆科植物根瘤菌的多样性还表现在某些来自同一种寄主植物根瘤菌的多样性方面，如分离自山槐、白车轴草、合萌、铁扫帚上的同一种寄主植物内的根瘤菌分别聚在不同的表观群；且来自山槐、合萌、铁扫帚上的根瘤菌既有快生型，又有慢生型。

For example, soybean is infected by Bradyrhizobium japonicum while peas nodulate with Rhizobium leguminosarum and clover with Rhizobium trifolii.

波顿（1984）根据对根瘤菌的专一性把豆类作物可分为45组，例如，大豆被大豆慢生根瘤菌细菌侵染，而豌豆被豌豆根瘤菌侵染结瘤，三叶草被三叶草根瘤菌侵染。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。