Burkholderia susongensis L226提高玉米对土壤钾素利用效应及其机制研究

发布时间：2018-06-04 18:13

本文选题：钾素流失 + 钾肥利用率　；参考：《南京农业大学》2015年硕士论文

【摘要】：近些年来,我国对钾肥的需求与使用量在逐年增加。然而每年进口的钾肥使用量占据国内钾肥总需求量的70%以上,严重威胁了我国的粮食安全。与此同时,由于农业生产中的钾肥过度使用,最终导致了低的钾肥利用率。本研究具有产胞外多糖的植物促生细菌提高植物对土壤钾素利用以及减少钾肥淋失的微生物调控机制,对于缓解我国缺钾压力,保障粮食产量具有重要意义。选取了实验室保藏的六株产胞外多糖菌株(L226、M72、M78、B23、B17-1、C52)作为供试菌株,筛选具有促生特性且生物量大的植物促生细菌。试验发现,L226与B17-1较其余菌株,能产铁载体、IAA以及精氨酸脱羧酶,且能显著提高玉米干物质量,因此是较为合适的植物促生细菌。K~+吸附特性试验发现,菌株L226吸附钾素并缓慢释放K~+的趋势最为理想。随着菌株进入指数生长期,开始生成胞外多糖等物质吸附K~+,使得发酵液中K含量降低,第10d时(菌株处于生长稳定期)达最大吸持率8.40%。之后随着菌体的衰亡,细胞裂解缓慢释放K~+,发酵液中的K含量又上升,这与菌体内钾素含量变化趋势相反。结合钾离子吸附特性试验与植物促生特性,最终选取菌株L226作为盆栽与淋滤试验的菌株,通过与不同梯度钾肥配施,研究植物促生细菌如何提高玉米对土壤钾素利用以及减少钾肥淋失的调控机制。结果表明,1)淋滤试验中,菌株L226通过产生的胞外多糖的吸附作用,吸附钾素从而减少钾肥的淋失,且随着钾肥比率的增加,菌株对钾的吸持效果越好;2)盆栽试验中,在80%K的施钾水平下,菌株L226对玉米生长以及吸收土壤钾素的效应最好,且以接菌后第20 d作用最明显;3)接菌能显著提高根际土壤细菌数量与多糖含量,促进植物对养分的吸收;4)接菌能显著提高玉米钾含量、钾素累积量、钾素生理效率、钾肥利用率以及可溶性糖含量,从而提高植株对土壤钾素的利用;5)不施钾条件下,菌株通过动员土壤中的钾供植物利用;而施钾条件下,菌株可以促进非根际土中的交换态钾向根际转移,并将根际交换态钾转换为水溶性钾,通过钾素形态的改变,提高玉米对钾素的利用;6)试验后期,菌体细胞衰亡,释放的钾素供植物吸收利用,起到了较好的保钾与释钾功能。对实验室保藏菌株L226进行了分类学地位研究,综合菌株L226的基因型特征、形态学特征、生理生化特性以及化学组分特征,确定菌株L226为Burkholderia属的一个新种,命名为Burkholderiasusongensis sp.nov.。
[Abstract]:In recent years, the demand and use of potash fertilizer in China is increasing year by year. However, the annual import of potash fertilizer occupies more than 70% of the total demand for potash fertilizer in China, which seriously threatens the food safety of China. At the same time, due to the excessive use of potash fertilizer in agricultural production, the utilization rate of potassium fertilizer is low. The biological control mechanism of plant growth promoting bacteria of polysaccharide to improve the utilization of soil potassium and reduce the loss of potassium fertilizer is of great significance for alleviating the potassium deficiency in China and ensuring grain yield. Six strains of extracellular polysaccharide (L226, M72, M78, B23, B17-1, C52) in the laboratory are selected as the tested strains, and the strains are screened to promote the growth of the bacteria. The experiment found that L226 and B17-1 can produce iron carrier, IAA and arginine decarboxylase, and can significantly improve the quality of dry matter of maize. Therefore, it is a more suitable test for.K~+ adsorption characteristics of plant growth promoting bacteria. It is the most ideal of the strain L226 to adsorb potassium and slow release K~+. When the strain entered the exponential growth period and began to produce extracellular polysaccharide and other substances to adsorb K~+, the content of K in the fermentation broth was reduced, and 10d (strain was in the stable period of growth) reached the maximum holding rate of 8.40%.. With the decay of the bacteria, the cell lysis slowly released K~+, and the content of K in the fermentation broth increased, which was related to the change trend of potassium content in the bacteria. In combination with potassium ion adsorption characteristics test and plant growth promoting characteristics, the strain L226 was selected as the strain of potted and leachate test. Through the application of different gradient potassium fertilizer, the regulation mechanism of plant growth promoting bacteria on soil potassium utilization and reduction of potassium leaching was studied. The results showed that, 1) the strain L226 was used in the leaching test. After the adsorption of extracellular polysaccharide, potassium fertilizer was adsorbed to reduce the leaching loss of potassium fertilizer, and with the increase of potassium fertilizer ratio, the better the absorption effect of the strain on potassium; 2) in the pot experiment, the effect of strain L226 on the growth of maize and the absorption of potassium in soil was best under the potassium application level of 80%K, and the effect of twentieth d after receiving bacteria was the most obvious; 3) Bacteria can significantly increase the number of bacteria in rhizosphere soil and polysaccharide content, promote the absorption of plants to nutrients; 4) the increase of potassium content, potassium accumulation, potassium physiological efficiency, potassium fertilizer utilization and soluble sugar content can improve the utilization of potassium in soil; 5) under the condition of non potassium application, the strain can mobilize the soil by mobilizing the soil. Potassium is used for plants, but under the condition of potassium application, the strain can promote the transfer of exchangeable potassium in the non rhizosphere soil to the rhizosphere, and convert the exchangeable potassium in the rhizosphere to water-soluble potassium. By the change of the potassium form, the use of potassium in maize is improved. 6) the later period of the experiment, the cell cell decline and the release of potassium for plant absorption and utilization, it has played a better guarantee. The function of potassium and potassium release. The taxonomic status of the laboratory preserved strain L226 was studied. The genotypic characteristics, morphological features, physiological and biochemical characteristics and chemical composition characteristics of the strain L226 were synthesized, and the strain L226 was a new species of Burkholderia, named Burkholderiasusongensis sp.nov...
【学位授予单位】：南京农业大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：S513;S182

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