本研究从南京板桥镇的灰潮土中，筛选出了一株高效固氮解磷菌，命名为 JX14，其固氮酶活性达 C2H4 38.9 nmol/(h·ml)，对磷酸三钙的转化量达 96.19 mg/L。通过形态观察、生理生化特征及 16S rDNA 基因序列分析，确定 JX14 为贪噬菌属(Variovorax sp.)。在温室条件下进行花生盆栽试验，结果表明，接种 JX14 菌株的处理，土壤NH₄⁺ -N、NO₃^– -N、矿质氮含量较不接菌处理分别提高了 1.08、1.18、1.16 倍，土壤有效磷含量提高了 18.14%。花生根系总长、表面积、体积以及根尖数，较对照分别提高了 1.61、1.28、1.37、1.12 倍，花生根系变得更长更粗并且具有更多的分支，增强了根对土壤中营养元素的吸收，花生地上部鲜重、株高显著提高了 44.78%、14.10%，花生全氮磷钾含量分别显著提高了 35.14%、171.43%、133.33%。该结果为植物促生菌 JX14 在农业生产上的应用提供了理论依据和研究基础。

Plant growth-promoting bacteria (PGPB) can improve plant growth and play a major role in the development of plants. The present study was concerned with a PGPB (defined as JX14) isolated from calcareous alluvial soil and was analyzed for its plant growth-promoting effect on peanuts. The nitrogenase activity of JX14 was C2H4 38.9 nmol/(h·ml), the transformation amounts of tricalcium phosphate was 96.19 mg/L. Strain JX14 was identified as Variovorax sp. (GenBank Accession No. JX424612) based on the morphological, physiological and biochemical characteristics and 16S rRNA gene sequences analysis. In pot experiments, compared to the non-inoculated treatment, inoculation with JX14 significantly increased soil NH₄⁺ -N, NO₃^– -N, mineral N and available phosphorus concentrations by 1.08, 1.18, 1.16-fold and 18.14%, which led to 1.61, 1.28, 1.37, 1.12-fold significant increases in the root length, surface area, root volumes and root tips of peanuts, respectively. In addition, plant morphological characteristics such as wet weight and height significantly increased by 44.78% and 14.10%, and plant nutrient content such as total N, total P and total K of peanuts significantly increased by 35.14%, 171.43% and 133.33%, respectively. The IAA-producing bacterial strain JX14 has promising application in promoting plant growth in peanuts production.

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国家自然科学基金项目(30970537、41401274)资助