分离自牧草根际四株促生菌株(PGPR)互作效应研究

摘要

利用钼蓝比色、显色和Salkowski比色等方法测定了筛选自苜蓿、白三叶和红三叶根际的4株优良PGPR菌株间的拮抗反应、单独和混合培养菌株的溶磷和分泌植物生长素(IAA)能力、培养液pH值和有机酸总量变化及其彼此之间的相关性.结果表明,各菌株间无拮抗反应,可以混合使用.无机磷培养液中,菌株Hsg+lhs11组合处理有效磷增量(536.2 mg/L)最大,Hsg+ ls1-3+ lhs11组合次之(475.6 mg/L).Hsg+lhs11组合菌株处理有效磷增量呈现“1+1＞2”的加成效应,Hsg+ ls1-3+ lhs11处理有效磷增量较单菌株处理时显著提高(P＜0.01),但未表现“1+1+1＞3”的溶磷效果.有机磷培养液中,lhs11处理有效磷增量(11.11 mg/L)最大,Hsg+ ls1-3+ lhs11组合次之(9.20 mg/L),Hsg+ls1-3+ lhs11组合有效磷增量显著高于其他组合处理.各处理菌株培养液有效磷增量与pH值、有效磷增量与总有机酸量、pH值和总有机酸量之间存在线性相关.单菌株及菌株组合均具有分泌IAA的能力,分泌量在0.212～9.331 μg/mL,Hsg+ lhs11组合菌株培养液IAA含量显著高于单菌株Hsg和lhs11(P＜0.01),并呈现“1+1＞2”的加成效果.综合各处理的促生特性,组合Hsg+ lhs11和Hsg+ ls1-3+ lhs11菌株间互作效应较强,有望成为研制复合菌肥的最佳菌株组合.%Four PGPRs (plant growth promoting rhizobacteria) were isolated and screened from the rhizo-spheres of Medicago sativa , Trifolium repens and Trifolium pratense. Antagonistic reactions, the ability of solubilizing phosphate and the production of IAA (Indoleacetic Acid) by strains in both single and compound culture, together with the pH values of culture solutions and total contents of organic acid were tested. The a-bility to solubilize phosphate and produce IAA were determined by molybdenum-bule and Salkowski colorime-try. The relativity of isolated bacterial strains was analyzed. The results showed that there was no antagonistic reaction between different single strains so that compound strains could be utilized. In a bio-phosphorus culture solution, the Hsg+lhsll compound strain had the highest increment of effective-phosphorus (536. 2 mg/L), while the Hsg + lsl-3 + lhsll compound strain was second (475. 6 mg/L). Effective-phosphorus increments gave additional effects of "1 + 1＞2" in Hsg+lhsll compound strains. Effective-phosphorus increased in Hsg + lsl-3 + lhsll compounding strains compared with single strain treatmenst (P＜0. 01), but there was no additional effect with "1 + 1 + 1＞3" Hsg+lsl-3 + lhsll compound strains. In organic phosphorus culture solution, the lhsll strain had the highest effective-phosphorus increment (11. 11 mg/L), and Hsg+lsl-3 + lhsll compound strains was second (9. 20 mg/L). The effective-phosphorus increment with the Hsg+lsl-3 + lhsll compound strains was higher than in other compounding treatments. There were linear correlations between effective-phosphorus increment and pH value, effective phosphorus increment and total content of organic acid, pH value and total content of organic acid. Single strains and compound strains both had the ability to produce IAA, between 0. 212 - 9. 331 mg/L. The IAA content in the Hsg+lhsll compound treatment was higher than that of the single strain Hsg or lhsll treatments (P<0. 01), both of which presented a "1 + 1＞2" additional effect. Consider the growth-promoting effects of different treatments, the Hsg+lhsll compound strains and Hsg+lsl-3 + lhsll compound strains had better interaction effects so they have the potential to develop the optimal compound strain fertilizer.