水稻根际土壤溶磷菌的分离、鉴定及对水稻的促生作用

【目的】为明确水稻根际溶磷菌株溶磷能力及其对水稻植株及根际土壤磷含量的影响。【方法】利用溶磷圈法从水稻根际土壤中分离获得具有较强溶解Ca3(PO4)2能力的2株细菌NDW1和NDW3,根据16S r DNA对菌株进行鉴定。以NBRIP为基础培养基,通过正交试验对2株菌株利用氮源、碳源及初始p H进行优化,鉴定菌株的吲哚乙酸(IAA)分泌量,研究溶磷菌对水稻的促生作用,以及对土壤速效磷和水稻幼苗全磷含量的影响。【结果】菌株NDW1和菌株NDW3分别被鉴定为Enterobacter sp.和Serratia sp.,2株菌株溶磷的最佳条件组合均为葡萄糖、蛋白胨及初始p H 6。2株菌株24 h内最高溶磷量分别为294.95和312.93μg·m L-1,且都可分泌IAA。土培和沙培条件下,溶磷菌NDW3对水稻株高、根长、最大叶长及地上干质量都有明显的促进作用,并且NDW3在2种种植条件下均显著增加了根际土壤速效磷及水稻植株全磷含量。【结论】从水稻根际土壤分离获得2株溶磷能力较好的细菌菌株Enterobacter sp.NDW1和Serratia sp.NDW3,菌株NDW3对水稻的促生作用强于菌株NDW1。

Isolation and identification of phosphate solubilizing bacteria from rice rhizosphere soil, and promoting effect on rice plant growth

Objective] To determine the ability of phosphate dissolving of phosphate solubilizing bacteria ( PSB) in rice rhizosphere, and study the effect of PSB on soluble phosphorus contents in rice plants and rhizosphere soil. Method] Two bacteria strains NDW1 and NDW3 with strong ability of dissolving Ca3 ( PO4 ) 2 were isolated from rice rhizosphere soil based on the halo zone formation on media due to phosphate solubilization, and identified by 16S rDNA method. Phosphorus dissolving conditions of two strains were optimized by orthogonal test with NBRIP as the basic medium. The production of indole-3-acetic acid( IAA) were determined. The effects of NDW1 and NDW3 on promotion of rice growth, the soil available phosphorus contents and plant total phosphorus contents were studied. Result]NDW1 and NDW3 were identified as Enterobacter sp. and Serratia sp. . The best combination of carbon, nitrogen source and pH for phosphate solubilition by NDW1 and NDW3 were both the combination of glucose, peptone and pH 6 . The highest phosphorus contents dissolved by NDW1 and NDW3 were 294. 95 and 312. 93 μg · mL-1 after 24 h incubation, respectively. Both PSB could produce IAA. NDW3 significantly increased the shoot height, root length, maximum leaf length and above-ground dry mass of rice plant in both soil culture and sand culture. NDW3 also significantly increased the contents of soil available phosphorus and rice total phosphorus under both culture conditions.Conclusion]Enterobacter sp. NDW1 and Serratia sp. NDW3 isolated from rice rhizosphere soil have strong ability of phosphate dissolving. The growth promoting effect of NDW3 for rice plant is better than that of NDW1.