Dong Yan, Yang Zhi-xian, Dong Kun, Tang Li, Zheng Yi, Hu Guo-bin
College of Resources and Environment, Yunnan Agricultural Universi-Kunming 650201, China.
Ying Yong Sheng Tai Xue Bao. 2013 Apr;24(4):1101-8.
A field plot experiment was conducted to study the effects of different nitrogen (N) application rates on the microbial functional diversity in faba bean rhizosphere and the relationships between the microbial functional diversity and the occurrence of faba bean fusarium wilt. Four nitrogen application rates were installed, i. e. , N0(0 kg hm-2 , N1 (56. 25 kg hm-2) , N2(112. 5 kg hm-2), and N3 (168.75 kg hm-2), and Biolog microbial analysis system was applied to study the damage of faba bean fusarium wilt and the rhizospheric microbial metabolic functional diversity. Applying N (N1 N2, and N3) decreased the disease index of faba bean fusarium wilt and the quantity of Fusarium oxysporum significantly, and increased the quantities of bacteria and actinomyces and the ratios of bacteria/fungi and actinomyces/fungi significantly, with the peak values of bacteria and actinomyces, bacteria/fungi, and actinomyces/fungi, and the lowest disease index and F. oxysporum density in N2. As compared with N0, applying N increased the AWCD value significantly, but the effects of different N application rates on the ability of rhizospheric microbes in utilizing six types of carbon sources had definite differences. Under the application of N, the utilization rates of carbohydrates, carboxylic acids, and amino acids by the rhizospheric microbes were higher. Principal component analysis demonstrated that applying N changed the rhizospheric microbial community composition obviously, and the carbohydrates, carboxylic acids, and amino acids were the sensitive carbon sources differentiating the changes of the microbial community induced by N application. Applying N inhibited the utilization of carbohydrates and carboxylic acids but improved the utilization of amino acids and phenolic acids by the rhizospheric microbes, which could be one of the main reasons of applying N being able to reduce the harm of faba bean fusarium wilt. It was suggested that rationally applying N could increase the quantities of rhizospheric bacteria and actinomyces, alter the microbial metabolic function, and decrease F. oxysporum density, being an effective measure to control the occurrence of faba bean fusarium wilt.
通过田间小区试验，研究了不同施氮量对蚕豆根际微生物功能多样性的影响，以及微生物功能多样性与蚕豆枯萎病发生之间的关系。设置了4个施氮量水平，即N0（0 kg·hm⁻²）、N1（56.25 kg·hm⁻²）、N2（112.5 kg·hm⁻²）和N3（168.75 kg·hm⁻²），采用Biolog微生物分析系统研究蚕豆枯萎病的危害及根际微生物代谢功能多样性。施用氮肥（N1、N2和N3）显著降低了蚕豆枯萎病的病情指数和尖孢镰刀菌数量，显著增加了细菌和放线菌数量以及细菌/真菌和放线菌/真菌的比例，其中细菌和放线菌数量、细菌/真菌和放线菌/真菌比例的峰值以及最低病情指数和尖孢镰刀菌密度均出现在N2处理。与N0相比，施用氮肥显著提高了AWCD值，但不同施氮量对根际微生物利用6种碳源能力的影响存在一定差异。在施氮条件下，根际微生物对碳水化合物、羧酸和氨基酸的利用率较高。主成分分析表明，施用氮肥明显改变了根际微生物群落组成，碳水化合物、羧酸和氨基酸是区分施氮诱导微生物群落变化的敏感碳源。施用氮肥抑制了根际微生物对碳水化合物和羧酸的利用，但提高了对氨基酸和酚酸的利用，这可能是施用氮肥能够减轻蚕豆枯萎病危害的主要原因之一。研究表明，合理施用氮肥可以增加根际细菌和放线菌数量，改变微生物代谢功能，降低尖孢镰刀菌密度，是控制蚕豆枯萎病发生的有效措施。
