石漠化地区豆科植物根瘤菌降解碳酸钙、镁能力研究

微生物对岩溶地区岩石风化、成土具有明显的促进作用，为了筛选出能够促进碳酸盐岩风化、加快成土速率的优势根瘤菌菌株，将其与豆科植物建立共生体系，进行石漠化地区修复与治理，实验以分离自云南石漠化地区的9株豆科植物根瘤菌为研究对象，将9株根瘤菌接种于加有难溶性碳酸钙或碳酸镁的液体培养液中，28.5℃、160 r·min-1摇床培养15 d，于0、1、3、6、10、15 d取样2 mL，每个样3个平行；将样品加入到10 mL体积比5∶1的硝酸高氯酸消化液中浸泡过夜，放在电热板上缓慢加热至溶液澄清透明，分别用含La3＋2%的盐酸溶液定容至10 mL，空白用同样方法处理；最后采用原子火焰吸收方法测定样品中Ca2＋和Mg2＋含量，筛选出对碳酸盐岩主要成分碳酸钙和碳酸镁具有强降解作用的根瘤菌菌株。结果表明：热带根瘤菌Rhizobium tropici （SWFU09）和根瘤菌Rhizobium sp.（SWFU02）对碳酸钙降解作用最强；对碳酸镁降解作用最好的菌株为根瘤菌Rhizobiumsp.（SWFU03）、热带根瘤菌Rhizobium tropici（SWFU05）和慢生根瘤菌Bradyrhizobium sp.（SWFU01）。溶液pH值对碳酸镁降解作用具重要的影响，对碳酸钙降解作用影响不大，说明根瘤菌代谢产生的酸性物质（有机酸、氨基酸）对碳酸钙和碳酸镁降解作用有一定影响，但不是唯一影响因素；也可能是微生物代谢产生的有机配体（基）吸附碳酸钙和碳酸镁表面，与水体中的成分形成复合物，改变溶解的平衡，置换出Ca2＋和Mg2＋。

Leguminous Plants Rhizobia Degradation of Calcium Carbonate and Magnesium Carbonate

Microorganism played an obvious role in facilitating the reaction rate of rock weathering and soil formation, in order to attain dominant rhizobium strains promoted the rock weathering and speed up the rate of soil rhizobium, the dominant rhizobium strains established the symbiotic system with leguminous plants to repair and manage the rocky desertification areas, the thesis studied on the 9 strains from leguminous plants rhizobia by the test of doing the strains in liquid medium with difficult soluble calcium carbonate or magnesium carbonate, then, handled with 28.5℃, 160 r·min-1 and 15 d table culture, sampled 2 ml of three at 0, 1, 3, 6, 10, 15 d. Samples added into the 10 mL digestive juices for a night, nitric acid and perchloric acid volume ratio was 5 to 1 of the digestive juices, heating Slowly, get clear solutions, the capacity to 10 mL by adding 2% hydrochloric acid solution which contain La3＋,the same do with blank,used the flame atomic absorption method to determin contents of Ca2＋ and Mg2＋ in the samples parallel. We eagered to obtain the certain strains had strong degradation of calcium carbonate or magnesium carbonate. The results showed that the best calcium carbonate degradation strains wereRhizobium tropici （SWFU09） andRhizobium sp. （SWFU02）, the best strains of magnesium carbonate degradation wereRhizobiumsp. （SWFU03）, Rhizobium tropici（SWFU05） andBradyrhizobium sp. （SWFU01）. The solution pH had an important influence on degradation of magnesium carbonate, but not obvious on calcium carbonate degradation. We could have a conclusion： acid producted by microbial metabolism had a certain influence on degradations of calcium carbonate and magnesium carbonate, but it was not the only factor. Organic ligand （base） also producted by microbial metabolism might adsorpt on calcium carbonate or magnesium carbonate surface, it could form compounds with ingredients in the water, change the balance of dissolution, Ca2＋ and Mg2＋were replaced.