黄瓜根际对羟基苯甲酸降解菌的分离鉴定及特性的研究

发布时间：2018-02-11 18:25

本文关键词： 对羟基苯甲酸抗氧化酶土壤酶原儿茶酸 Ensifer adhaerens Streptomyces griseoruber Streptomyces canus　出处：《山东农业大学》2015年硕士论文　论文类型：学位论文

【摘要】：黄瓜是我国主要栽培蔬菜之一,温室栽培的连续种植方式容易引起连作障碍。对羟基苯甲酸(p-hydroxybenzonic acid,PHBA)是引起连作障碍的主要自毒物质之一。本实验从连作黄瓜根际土中筛选PHBA降解菌,研究降解菌的生理特性,降解菌对黄瓜抗氧化酶、土壤酶活性的影响,评估其对作物连作的缓解作用。具体研究结果如下,(1)筛选出对PHBA降解能力高的3株菌株。结合生理生化和分子鉴定结果,放线菌GLY-P1和GLY-P2分别被鉴定为Streptomyces griseoruber和Streptomyces canus,细菌GLY-P3被鉴定为Ensifer adhaerens。(2)Streptomyces griseoruber GLY-P1和Streptomyces canus GLY-P2在32?C、p H10、PHBA初始浓度为0.5g/L条件下降解率最高。在偏碱土壤中,Streptomyces griseoruber GLY-P1和Streptomyces canus GLY-P2降解率较高。Ensifer adhaerens GLY-P3最适降解条件为温度30?C,p H7,PHBA初始浓度为0.5g/L,氮源为硫酸铵,接种量8%(8×109cfu)。在最优降解条件下,12h内Ensifer adhaerens GLY-P3降解PHBA99.2%。(3)推测Streptomyces griseoruber GLY-P1、Streptomyces canus GLY-P2和Ensifer adhaerens GLY-P3代谢PHBA途径可能为原儿茶酸途径。在32?C、p H7、PHBA初始浓度为0.5g/L条件下,Streptomyces griseoruber GLY-P1和Streptomyces canus GLY-P2发酵液中原儿茶酸的最大含量分别为3.2mg/L和3.8mg/L。(4)将菌株Streptomyces griseoruber GLY-P1和Streptomyces canus GLY-P2置于PHBA环境中,体内SOD、CAT、DHAR和APX活性发生明显改变,菌株Ensifer adhaerens GLY-P3处于PHBA环境中,体内SOD、CAT、DHAR和MDHAR活性发生明显改变,说明在响应PHBA胁迫中,SOD、CAT、DHAR和APX在菌株Streptomyces griseoruber GLY-P1和Streptomyces canus GLY-P2起主要作用,SOD、CAT、DHAR和MDHAR在菌株Ensifer adhaerens GLY-P3起主要作用。(5)当在每克土壤中施加220微克PHBA时,黄瓜叶片中H2O2、O2.-、MDA含量和SOD、POD、APX、DHAR活性都明显升高,当土壤中施加GLY-P3时,黄瓜中H2O2、O2.-、MDA含量和SOD、CAT、POD活性都明显降低,表明PHBA对黄瓜造成胁迫作用,GLY-P3缓解了PHBA对黄瓜的胁迫作用。土壤中PHBA的施加,使黄瓜根际土壤磷酸酶、脲酶和蔗糖酶活性都普遍的升高了而过氧化氢酶活性降低。GLY-P3的施加使过氧化氢酶活性明显的升高了,土壤磷酸酶、脲酶和蔗糖酶活性都普遍的降低了,缓解了PHBA对土壤酶活的影响。结果表明Ensifer adhaerens GLY-P3能通过调节黄瓜叶片抗氧化酶、土壤的酶活性,缓解黄瓜的连作障碍。
[Abstract]:Cucumber is one of the main cultivated vegetables in China. Continuous planting in greenhouse is easy to cause continuous cropping obstacle. P-hydroxybenzonic acidonic acid (p-hydroxybenzoate) is one of the main autotoxic substances causing continuous cropping. In this experiment, PHBA degrading bacteria were screened from the rhizosphere soil of continuous cropping cucumber, and the physiological characteristics of degrading bacteria were studied. The effects of degrading bacteria on antioxidant enzymes and soil enzyme activities of cucumber were evaluated. The results were as follows: 1) three strains with high degradation ability of PHBA were screened, and the results of physiological, biochemical and molecular identification were combined with the results of physiological, biochemical and molecular identification. Actinomycetes GLY-P1 and GLY-P2 were identified as Streptomyces griseoruber and Streptomyces Canus, respectively. Bacterial GLY-P3 was identified as Ensifer adhaerens.(2)Streptomyces griseoruber GLY-P1 and Streptomyces canus GLY-P2. The degradation rate was the highest at the initial concentration of 0.5 g / L. the optimum conditions for degradation of Streptomyces griseoruber GLY-P1 and Streptomyces canus GLY-P2 were 30? The initial concentration of Ensifer adhaerens GLY-P3 was 0.5 g / L, the nitrogen source was ammonium sulfate, and the inoculation amount was 8 脳 10 9 cfu.In the optimal degradation conditions, the degradation of PHBA99.2. 3 by Ensifer adhaerens GLY-P3 within 12 hours was deduced that Streptomyces griseoruber GLY-P 1 Streptomyces canus GLY-P2 and Ensifer adhaerens GLY-P3 metabolism PHBA pathway might be protocatecholic acid pathway. The maximum contents of protocatechuic acid in the fermentation broth of Streptomyces griseoruber GLY-P1 and Streptomyces canus GLY-P2 were 3.2 mg / L and 3.8 mg / L respectively at the initial concentration of 0.5 g / L). The strains Streptomyces griseoruber GLY-P1 and Streptomyces canus GLY-P2 were placed in PHBA environment. The activities of SODCATDHAR and APX were significantly changed. The Ensifer adhaerens GLY-P3 was in the PHBA environment, and the activities of MDHAR and DHAR were obviously changed. The results showed that in response to PHBA stress, APX and APX played a major role in Streptomyces griseoruber GLY-P1 and Streptomyces canus GLY-P2. Streptomyces griseoruber CATHAR and MDHAR played a major role in Ensifer adhaerens GLY-P3.) when 220 渭 g PHBA was applied to the soil per gram, the contents of H _ 2O _ 2O _ 2.-malondialdehyde and the activity of SODPOD _ (2) -malondialdehyde (PHBA) in cucumber leaves were significantly increased. When GLY-P3 was applied to the soil, the content of H _ 2O _ 2O _ 2.-malondialdehyde (MDA) and the activity of POD in cucumber were significantly decreased, which indicated that PHBA caused stress on cucumber and GLY-P3 alleviated the stress of PHBA on cucumber. The application of PHBA in soil resulted in phosphatase in cucumber rhizosphere. The activities of urease and sucrase increased generally, but the activity of catalase decreased. GLY-P3 significantly increased the activity of catalase, and the activities of phosphatase, urease and sucrase in soil were all decreased. The effect of PHBA on soil enzyme activity was alleviated. The results showed that Ensifer adhaerens GLY-P3 could alleviate the obstacle of continuous cropping by regulating the antioxidant enzyme activity and soil enzyme activity in cucumber leaves.
【学位授予单位】：山东农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S642.2;S182

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