核桃根际解磷.doc

核桃根际解磷、解钾、固氮菌株的筛选及分布特征研究森林保护学：崔晓亮 指导教师：朱天辉 教授微生物肥料作为一种绿色无公害的肥料，具有改善作物营养，提高土壤肥力，促进土壤中其它生命活动的进行和物质的转化，且无毒无害、无污染、成本低等特点，正越来越受到人们的重视，研制微生物肥料成为实现绿色农业的主要手段之一。目前，所有菌肥菌种绝大多数是从自然界中直接分离并经筛选得到的，有学者指出我国应成立国家生物肥料菌种资源库，将自然界中存在的具有某一特定功能如固氮、解磷、解钾等功能的菌株，作为一种特定的菌种资源，通过专门机构广泛收集菌种，组织科技人员在各种自然环境下筛选出新菌株，成立生物肥料菌种资源库。本试验结合四川核桃生产特点，在全省核桃主要产区，从核桃根际土壤中筛选出具有解磷、解钾、固氮功能的微生物肥料原始菌株，测定了菌株效价，对作用明显的优良菌株进行分类鉴定，并对其分布特征进行了探索，结果如下：（1）采用选择性培养基平板初筛和测定效价进行复筛相结合的方法，共筛选到微生物肥料菌株431株，从筛选得到的菌种数量看，解有机磷细菌解钾细菌解无机磷细菌固氮细菌，分别为134株，114株，94株和89株。经测定，在这431株细菌中，有132株效价较好，作为进一步研究的对象。（2）根据微生物的培养性状、培养特征、生理生化特征等指标，对所分离、纯化的各种微生物肥料菌株进行初步分类鉴定，对部分效价强的菌种采用16S rDNA技术进行分子生物学水平的鉴定，得到18个属50种，其中解无机磷细菌共8个属、解有机磷细菌6个属、固氮细菌7个属、解钾细菌4个属。（3）在各种功能菌的分布情况上，解有机磷细菌最丰富，平均值达20.9588105cfu/g，其次为解无机磷的细菌，而分离出最少的为解钾细菌，平均值仅为13.5632105cfu/g。微生物肥料菌株总生物量的最高值出现在土壤pH值在为7.04的南江，生物量为104.5765105cfu/g，而最低值出现在土壤pH值为8.60的汉源，仅为29.4834105cfu/g。（4）各地解无机磷细菌的生物量与土壤有机质呈显著正相关，而各地固氮细菌与土壤有机质是极显著正相关，而解有机磷细菌和解钾细菌则和土壤有机质相关性不大。而各种微生物肥料菌株生物量与土壤全N、全P和全K的相关性中，仅解钾细菌的生物量和土壤全K为显著相关性，其他均相关性不大（5）各种微生物肥料菌株，在各地的种群丰富度和多样性为：汉源、黑水两地的解无机磷细菌种群丰富，其多样性和丰富度指数均较大；汉源的解有机磷细菌种群丰富，其多样性和丰富度指数均较大；北川的解钾细菌种群丰富，其多样性和丰富度指数均较大；南江和兴文两地的固氮细菌种群丰富，其多样性和丰富度指数均较大。关键词：微生物肥料 解磷细菌 解钾细菌 固氮细菌 筛选AbstractAs a non-nuisance and green fertilizer, Microbial Fertilizer could improve crop nutrition, soil fertility and accelerate the process of other life activities in soil and material transformation. They also have many characteristics such as innocuity, harmless, non-pollution, low cost and so on. In these circumstances ，people have attached more and more importance to Microbial Fertilizer. Producing Microbial Fertilizer has become one of the central method to achieve green agriculture. At present, most Microbial Fertilizer and strains have been separated and filtrated from nature. Some scholars have pointed out that China should set up a national resource library of bacteria bio-fertilizer, collect the strains as a specifical resources in nature ,which with a particular function such as releasing Phosphorus,releasing Kalium and fixing nitrogen. Combined with juglans production in Sichuan,The research have screened the Microbial Fertilizers strains which with a particular function such as releasing Phosphoru, releasing Kalium and fixing nitrogen from Rhizosphere Soil of Juglans in the major production areas of Juglans in Sichuan, detected the ability of strains and identified the strains which has conspicuous effect. The results as follows: (1)By screenning from the selective medium and detecting the ability of strains，the research have screened 431 strains of Microbial Fertilizer. From the number of obtained strains, decomposing organic phosphorus bacteriadecomposing potassium bacteriadecomposing inorganic phosphorus bacterianitrogen-fixing bacteria. Their number were 134，114，94 and 89 classes separately. By measuring, there have 132 classes with better effect in the 431 strains to be the object of further study.(2)According to the target of cultivating characters, cultivating features, physiological and biochemical characteristics of microbe, the separated and purified strains of Microbial Fertilizer have been preliminarily classify and identified. For some strains with better effect, it used 16S rDNA technique to identify the level of molecular biology, and found 18 generas with 50 species. Among those, decomposing inorganic phosphorus bacterium with 8 generas, decomposing organic phosphorus bacterium 6 generas, nitrogen-fixing bacteria 7 generas,decomposing potassium bacteria 4 generas.(3) In the distribution of bacteria with various functions, decomposing organic phosphorus bacteria was most abundant, its average was 20.9588105cfu/g. The followed bacteria was decomposing inorganic phosphorus bacteria. Decomposing potassium bacteria was the least, its average was 13.5632105cfu/g only. The highest total biomass of Microbial fertilizer strains present toNanjiang with pH 7.04, its biomass was 104.5765105cfu/g. While the lowest in the soil with pH 8.60, its biomass was 29.4834105cfu/g only. (4)In all places,the biomass of decomposing inorganic phosphorus bacteria were significant positive correlation to the soil organic matter. The biomass of nitrogen-fixing bacteria were extremely significant positive correlation to the soil organic matter. While decomposing organic phosphorus bacteria and decomposing potassium bacteria have little relevance. In the relativities of Microbial Fertilizers strains with total nitrogen , total microbes and total kalium, the biomass of decomposing potassium bacteria has significant positive correlation to the soil total kalium. Other relativities were not distinct. (5)The population diversities and enrichness of the Microbial Fertilizers strains in each place showed as follows. The population diversities and enrichness of decomposing inorganic phosphorus bacteria were higher than others in Hanyuan and Heishui. the population diversities and enrichness of decomposing organic phosphorus bacteria were higher than others in Hanyuan. The population diversities and enrichness of decomposing potassium bacteria were higher than others i