植物根际促生菌剂的研发及其对芦苇生长发育的促进作用

发布时间：2018-02-26 08:14

本文关键词： 芦苇湿地植物根际促生菌解磷固氮　出处：《中国海洋大学》2015年硕士论文　论文类型：学位论文

【摘要】：芦苇湿地是重要的生态系统,具有较高的经济价值和生态价值。本文针对近年来辽河口芦苇湿地严重退化、生物量显著降低、生态功能明显下降等问题,分析了原因,以提高土壤中N、P元素含量和改善芦苇湿地微生境为角度,以促进芦苇生长为目的,进行芦苇根际促生菌剂的研发,并考察菌肥的施加对芦苇生长的影响。解磷菌和自生固氮菌是植物根际促生细菌的重要组成成分,可以将土壤中植物不能直接利用的磷转化成有效磷,将空气中的N：通过生物固氮作用供给植物生长,提高植物对氮、磷的利用。利用蒙金娜培养基、Ashby培养基等选择性培养基,从辽河口芦苇湿地根际土壤中筛选出3株解磷菌和3株固氮菌。分别将其接种到液体培养基中进行培养,检测菌液中可溶性正磷酸盐和氨氮的含量变化。结果显示,7天后,以不溶性无机磷[Ca3(PO4)2]为磷源培养的解磷菌液可溶性正磷酸盐的平均含量为95.2mg·L-1,解磷率为23.8%,其中菌株P2解磷能力最强,解磷率达到26.35%；以有机磷(卵磷脂)为磷源培养的解磷菌液可溶性正磷酸盐的平均含量为5.87mg·L-1,解磷率为65.2%,其中菌株P3解磷能力最强,解磷率达到73.4%；固氮菌菌液的氨氮平均含量为0.88mg·L-1,其中N2的固氮能力最强,菌液氨氮含量达到达到0.93mg·L-1。同时,通过室内栽种芦苇实验,监测芦苇生长状况和土壤肥力的变化。结果显示,35天后,施加菌液的芦苇与对照组相比,株高增长8%以上,生物量平均提高50%；施加菌液后土壤的肥力和活性明显提高,其中速效氮、有效磷、脲酶活性、磷酸酶活性以及微生物活性与初始值相比分别提高27%、60%、60%和66%和23%。此外,有三株菌还具有分泌植物生长激素(IAA)的能力。通过菌种鉴定,这三株解磷菌分别为Bacillus megaterium、Bacillus aquimaris、Pseudomonas plecoglossicida、固氮菌分别为Pseudomonas brassicacearum、Sphingomonas mali、Enterobacter asburiae。结合本研究结果和相关文献报道,这些菌种具备一定的解磷、固氮能力,同时也具备植物生防、促生、降解污染等多种功能,是制备PGPR的理想菌种。利用PCR-DGGE技术对施加菌剂后土壤微生物种群进行解析,发现促生菌剂在土壤中稳定存在并能成为优势种群,土壤细菌的多样性有所提高,且对土壤原有的微生物群落不会造成明显的干扰。综上所述,我们认为,这几株菌对芦苇生长具有显著的促进作用,为下一步菌种的优化、复配以及菌剂的制备和应用奠定基础,对芦苇群落的恢复和芦苇品质的提升具有潜在的应用价值。
[Abstract]:Reed wetland is an important ecosystem with high economic and ecological value. In view of the serious degradation of Reed wetland in Liaohe estuary in recent years, the paper analyzes the reasons for the serious degradation of Reed wetland, the significant decrease of biomass and the obvious decline of ecological function. In order to improve the content of N P in soil and improve the micro-habitat of Reed wetland, and to promote the growth of Reed, the research and development of rhizosphere growth-promoting agent of Reed were carried out. The effects of microbial fertilizer on the growth of Reed were also investigated. Phosphorus releasing bacteria and autogenous nitrogen-fixing bacteria are important components of rhizosphere promoting bacteria, which can convert phosphorus that plants can not use directly into available phosphorus in soil. The N in the air was supplied to plant growth through biological nitrogen fixation, and the utilization of nitrogen and phosphorus in plants was improved. The selective medium, such as Ashby medium, was used in Montana medium. Three phosphorus releasing bacteria and three nitrogen-fixing bacteria were isolated from rhizosphere soil of Reed wetland in Liaohe estuary and cultured in liquid medium to detect the changes of soluble orthophosphate and ammonia nitrogen in the liquid medium. The average content of soluble orthophosphate in the solution cultured with insoluble inorganic phosphorus [Ca3(PO4)2] was 95.2 mg 路L ~ (-1), and the phosphorus release rate was 23.8mg 路L ~ (-1). The average content of soluble orthophosphate was 5.87 mg 路L ~ (-1) and the phosphorus release rate was 65.2 mg 路L ~ (-1), among which the phosphorus releasing ability of strain P3 was the highest. The average ammonia-nitrogen content of nitrogen fixing bacteria solution was 0.88 mg 路L -1, and the nitrogen fixation ability of N 2 was the strongest, and the ammonia nitrogen content of bacteria liquid reached 0.93 mg 路L -1. At the same time, the experiment of growing Reed in laboratory was carried out. The results showed that after 35 days, the plant height and biomass of Reed treated with bacterial solution increased by more than 8%, and the soil fertility and activity increased obviously after application of bacteria solution. The available nitrogen, available phosphorus, urease activity, phosphatase activity and microbial activity were increased by 2760% and 66%% and 23.3%, respectively, compared with the initial value. In addition, three strains also had the ability to secrete plant growth hormone (IAA). The three strains were Bacillus megaterium aquimarisus Pseudecoglossicida.The nitrogen-fixing bacteria were Pseudomonas brassica acearum malioronas maliorus enterobacter buriae.According to the results of this study and the related literature, these strains have the ability of phosphorus dissolving, nitrogen-fixing, plant growth control, growth promotion, and so on. Biodegradable contamination and other functions are ideal strains for the preparation of PGPR. Using PCR-DGGE technique to analyze the soil microbial population after application of microbial agents, it is found that the bacteriostat is stable in soil and can become a dominant population. The diversity of soil bacteria has been improved, and the original microbial community of soil will not be disturbed obviously. In conclusion, we think that these bacteria can promote the growth of Reed significantly and optimize the species for the next step. The preparation and application of the compound, as well as the preparation and application of the fungicides, have potential application value for the restoration of Reed community and the improvement of Reed quality.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S482.8;S564.2

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