不同植被土壤好气性自生固氮菌的时空变化格局及其菌株的初步筛选  

Quantitative distribution and preliminary selecting strains of the soil azotobacter in forest with different vegetation types

作　　者：王贵[1,2] 赵骥民[2] 郝清玉[1] 覃青青[1] 黄良春[1] 

机构地区：[1]海南师范大学生命科学学院热带动植物生态学省部共建教育部重点实验室,海南海口571158 [2]长春师范学院生命科学学院,吉林长春130032

出　　处：《广东农业科学》2013年第13期60-64,共5页Guangdong Agricultural Sciences

基　　金：海南省自然科学基金(311048);国家科技支撑计划项目(2012BAC18B04);国家自然科学基金(31060092)

摘　　要：主要分析了青皮天然林与木麻黄人工林等其他植被类型在土壤好气性自生固氮菌数量分布方面的差异及较强固氮能力菌株的分离和筛选。在石梅湾的8种不同植被类型样地，于不同季节取样4次，每次均取0～10cm及10～20cnl两个土层的根际土与根外土，用改良阿须贝培养基、MPN法计数土壤好气性自生固氮菌并初步筛选具有较强固氮能力的菌株。结果表明：本区土壤好气性自生固氮菌的时间分布极不均匀，且空间分布明显受到时间的影响。从时间分布来看，在一个年周期中，4月固氮菌数量最多，而7月最少，两者差异显著，此后数量又逐渐增加；从空间分布来看，随采样时间不同，植被、取样深度、植物根系、样地地势等条件均对土壤好气性自生固氮菌数量分布也有所不同，这些条件归根到底是通过改变土壤的氮素营养供给，土壤的水、热、气条件来影响固氮菌的分布；同时各植被类型的好气性自生固氮菌数量季节变化幅度也有异，处于高级别演替阶段青皮过伐林及混交林的季节变化明显小于较低演替阶段的灌丛、次生青皮林及木麻黄林。研究还分离了15个具有潜在固氮能力的菌株，并筛选出4个固氮能力较强的菌株．为进一步在海防林的建设及青皮林的保护中研究利用植物促生菌做了初步探索和准备。Selected 8 plots with different vegetation types in the nature Reserve for Vatica mangachpoi forest in Shimei Bay, rhizosphere and non-rhizosphere soil samples of 0-10 cm and 10-20 cm in these plots was taken at April, July, October, and December. Then the most probable number （MPN） method was used to investigate the quantitative distribution, isolated and preliminai7 selected strains which had stronger Nitrogen-fixing ability with Ashby medium in this area. Results showed that： the quantitative distribution of the soil azotobacter in this area is heterogeneity both time and space, and the space distribution was effected obviously by time. Judging from the time, the number of soil azotobacter was least in July, then its number increase slowly, the number was most until April. In space distribution, it had different results in each time, and is effeeted by vegetation, sampling depth, plant root system and terrain of each plot, these factors were all effect the quantitative distribution of soil Azotobacter by change the Nitrogen supply, water, thermal, and air of soil. In this research, 15 strains of azotobacter were isolated and 4 strains which had stronger Nitrogen-fixing ability was selected, it was the prepare that to use PGPR in the research that construct coastal protection forest and protect Vatica mangachpoi forest.

关 键 词：土壤 好气性自生固氮菌 数量分布 MPN法 植物促生菌 

分 类 号：S154.381[农业科学—土壤学]