Abstract: In order to research and develop plant growth promoting rhizobacteria (PGPR) microcapsules,and to investigate its effects on the growth of alfalfa and oats,this study used sodium alginate (SA) as the embedding agent,calcium chloride as the crosslinking agent,immobilization by embedding of single and complex strains. Evaluation indexes were microcapsule operational and sphericity,and the embedding rate,viable count and multiplication ratio were measured,to determine the best proportion. Salt and alkali tolerance of microcapsules was determined by using a liquid dosage form as a reference. Pot experiment was conducted to determine the effects of PGPR microcapsule on root length,root surface area,root diameter and root volume of alfalfa and oat. The results showed that:The PGPR microcapsules by treatment with SA 3%-CaCl₂ 4% had better mechanical strength. The embedding rate reached 91.70%,and the number of viable microcapsules after proliferation reached 1.08×10¹⁰ cfu·g^-1,which was proliferated 9.19 times. The concentration of PGPR microcapsules was higher than that of liquid bacteria at different saline-alkali concentrations,significantly improved the tolerance of strains to saline-alkali stress. The PGPR microcapsules can promote the growth of alfalfa and oat. The use of microcapsules increased alfalfa plant height by 31.79%,total root length,root surface area and root volume increased by 35.25%,40.02% and 30.43%,respectively. The plant height of oats was increased by 11.60%,the total root length,root surface area and root volume increased by 41.56%,25.01% and 105.83%,respectively. The optimal formula of PGPR microcapsule was SA 3%-CaCl₂ 4%. The plant height of alfalfa and oat could be significantly increased by PGPR microcapsules by increasing total root length at different root diameters,and improving root morphology. The effects on root growth of alfalfa and oats was better than liquid and solid microbial preparation.

Key words: Plant growth promoting rhizobacteria, Microcapsules, Alfalfa, Oats, Promoting effect

摘要： 为研制促生菌（Plant growth promoting rhizobacteria，PGPR）微胶囊剂，探究其对苜蓿、燕麦的促生效果，本研究以海藻酸钠（Sodium alginate，SA）为包埋剂，CaCl₂为交联剂，对单一菌株和复合菌株进行包埋，以微胶囊操作性和成球性为评价指标，并进行包埋率、活菌数及增殖倍数测定，确定最佳配比。以液体剂型为参比，测定微胶囊菌剂的耐盐和耐碱性，并对微胶囊菌剂进行盆栽试验，测定PGPR微胶囊剂对苜蓿和燕麦株高、总根长、根表面积、根平均直径和根体积的影响。结果表明：处理SA 3%-CaCl₂ 4%制作的微胶囊菌剂机械强度较好，包埋率达到91.70%，增殖后的微胶囊活菌数达到1.08×10¹⁰ cfu·g^-1，增殖9.19倍。不同盐碱浓度下微胶囊菌剂菌液浓度均高于液体菌剂，显著提高了菌株对盐碱胁迫的耐受能力。PGPR微胶囊剂对苜蓿和燕麦的促生效果显著，施用微胶囊菌剂使苜蓿株高增加31.79%，总根长、根表面积和根体积增加35.25%，40.02%和30.43%；使燕麦株高增加11.60%，总根长、根平均直径和根体积增加41.56%，25.01%和105.83%。确定PGPR微胶囊剂最佳配方为SA 3%-CaCl₂ 4%，施用PGPR微胶囊剂可明显提高苜蓿和燕麦的株高，以及不同根直径下的总根长，并改善根系形态，对苜蓿和燕麦根系生长的促生效果好于液体菌剂和固体菌剂。

关键词: 根际促生菌, 微胶囊, 苜蓿, 燕麦, 促生效果