摘　要：本研究从湖南省7个主要花生种植区采集的新鲜花生根瘤进行根瘤菌分离、纯化，共获得7株根瘤菌菌株。分别以湖南地方花生品种安化小籽花生、常宁小籽花生为测试品种，通过温室盆栽接种试验进行筛选，7株根瘤菌均能在两个花生品种上有效结瘤，其中R3-2、R4-6固氮能力最强。通过16S rDNA基因测序及序列比对，初步鉴定菌株R3-2属于日本慢生根瘤菌（Bradyrhizobium japonicum）。室内耐酸试验结果显示，菌株R3-2具有一定的耐酸性能，在pH为 5.4 （含pH>5.4 ）的改良的Keyser和Munns培养基上生长良好，且具有一定的重金属耐受性。在原生环境中进行的田间小区试验结果表明，70%常规施氮量并接种R3-2根瘤菌的处理组花生生长最佳，产量比对照组（常规施氮无接种根瘤菌）提高28.54%。菌株R3-2在固氮的同时具有一定的抵抗土壤中氢离子和重金属胁迫的能力，为我国南方花生栽培应用根瘤菌提供了一种新的选择。
关键词：花生；日本慢生根瘤菌；耐酸；产量；生物固氮
中图分类号：Q939.36                   　文献标志码：A                DOI：10.3969/j.issn.1007-7146.2025.01.006

Abstract: In this study, fresh peanut nodules were collected from seven major peanut growing areas in Hunan Province, and a total of 7 rhizobia strains were isolated and purified. The local peanut varieties Anhua small-seeded peanut and Changning small-seeded peanut varieties in Hunan Province were selected to test the capability of the 7 rhizobia strains by greenhouse pot inoculation experiments, and all 7 rhizobia strains could effectively form nodulation on the two peanut varieties, among which R3-2 and R4-6 showed the strongest nitrogen-fixing capability. Through 16S rDNA gene sequencing and sequence alignment, strain R3-2 was preliminarily identified as belonging to Bradyrhizobium japonicum. Further experiments demonstrated that the strain R3-2 had certain acid resistance and it grew well in modified Keyser and Munns medium while the pH is equal to 5.4 (including pH>5.4), and holding a certain tolerance to heavy metals. Finally, field experiments were carried out in the native environment of R3-2, and the results showed that peanut yield of the treatment group with 70% conventional nitrogen application and R3-2 rhizobia inoculation was the highest, which was 28.54% higher than that of the control group which is with conventional nitrogen application without rhizobia inoculation. With the fine effect on nitrogen fixation, as well as its positive tolerances on hydrogen ion and heavy metals, strain R3-2 is the potential rhizobium utilized in peanut cultivation in southern China.
Key words: Arachis hypogaea L.; Bradyrhizobium japonicum; tolerance of acids; yield; biological nitrogen fixation
（Acta Laser Biology Sinica, 2025, 34(1): 045-053）