解磷菌(Phosphate-solubilizing microorganisms)能够提高土壤中有效磷含量,增加土壤肥力,促进植物生长,缓解作物连作障碍。本研究从植物根际分离得到一株高效解磷菌并对其进行菌株鉴定,同时测定了其解磷和吲哚乙酸(indole acetic acid,IAA)分泌能力,及其对连作西瓜(Citrullus lanatus)幼苗生长的影响。经鉴定,筛选得到的菌株CL01为鞘氨醇单胞菌(Sphingomonas sp.),解磷能力强,最大解磷量可达到642.60 mg/L,其IAA最大分泌量可达到22.87 mg/L,经OD600=0.5浓度菌液处理后,连作西瓜幼苗的根干重、根长、根体积、根尖个数和毛根(d=0.0~0.5 mm)比例显著增加,根系平均直径显著降低。经OD600=1.0浓度菌液处理后,连作西瓜幼苗根尖数和毛根(d=0.0~0.5 mm)比例显著增加,西瓜幼苗根系平均直径显著降低;相比较而言,低浓度菌液对连作西瓜幼苗的促生效果更好。本研究表明,经筛选鉴定的鞘氨醇单胞菌菌株Sphingomonas sp.CL01具有较高的解磷能力,可分泌IAA,且能够优化西瓜根系形态,改善根系组成,在缓解西瓜连作障碍方面具有较好的应用前景。 Phosphate-solubilizing microorganisms can increase available phosphorus in soil, increase soil fertility, promote plant growth and alleviate obstacles in continuous cropping. In this study, a highly efficient phosphate-solubilizing bacterium was isolated from the plant rhizosphere and its strain was identified. Meanwhile, its ability to release phosphorus and indole acetic acid (IAA) was measured and its effects on the production of Citrullus lanatus Effect of seedling growth. The strain CL01 was identified as Sphingomonas sp., And its ability to dissolve phosphorous was high. The maximum amount of phosphorus solubilized reached 642.60 mg / L, and its maximum IAA secretion reached 22.87 mg / L. After OD600 = 0.5, the root dry weight, root length, root volume, root tip number and the proportion of hair root (d = 0.0-0.5 mm) increased remarkably in the continuous watermelon seedlings, and the mean root diameter decreased significantly. After OD600 = 1.0, the proportion of root tips and hairy roots (d = 0.0-0.5 mm) increased significantly and the average root diameter of watermelon seedlings decreased significantly. In contrast, Promote the growth of seedlings better. This study showed that the Sphingomonas sp. CL01 identified by screening has a higher ability to dissolve phosphorus, can secrete IAA, and can optimize the root morphology of watermelon to improve root composition, watermelon in the process to ease the obstacles to the succession have more Good application prospects.