杨树根际高效解钾细菌的分离筛选与鉴定

发布时间：2018-03-20 06:16

本文选题：解钾菌　切入点：杨树　出处：《南京林业大学》2016年硕士论文　论文类型：学位论文

【摘要】：我国的杨树产业非常发达,在全国分布广泛、品种数量齐全,杨树人工林面积超过其他国家人工林面积的总和,是我国速生用材的重要树种。但是近50年来,人工林的面积不断的扩大,轮伐期不断缩短,造成林地地力衰退,生产力下降,这与林地土壤肥力下降密切相关,其中钾素供应不足是突出而具普遍性的问题。钾是植物生长发育的必需养分。植物缺钾主要是由于土壤中能被其利用的有效钾很少,若能将土壤矿物钾转化为有效钾,则能有效改善目前缺钾的现状。解钾菌(potassium bacteria)是指从土壤中分离出来的,能分解钾长石等硅铝酸盐矿物,把难溶性的钾、磷、硅转变为可溶性状态,促进植物生长发育,提高产量的一类微生物。由于不同植物根际的解钾细菌的种类和数量存在差异,不同种类的解钾菌或不同菌株之间的解钾能力存在较大差异,所以从特定植物根际筛选高效解钾细菌的工作显得尤为重要。本研究从杨树根际土壤分离并筛选到3株高效解钾菌株JW-4、JW-5和JW-7,并进行了鉴定,对杨树的促生作用进行了研究,最后对促生效果最好的菌株JW-7的发酵条件进行了优化,为其以后的开发利用,解决我国土壤缺钾现状具有重要的现实意义,主要研究结果如下:利用硅酸盐培养基,采用稀释涂布平板法,初筛到13株解钾菌。对这13株菌进行摇瓶释钾试验,测定其解钾效率,从中筛选出3株高效解钾菌JW-4、JW-5和JW-7,其解钾效率分别达到26.30%、34.27%和38.70%。对3株高效解钾细菌采用形态学观察、生理生化特征及16SrDNA序列分析的方法进行了鉴定。JW-4、JW-5、JW-7皆为杆菌;都是革兰氏阴性菌、都没有芽孢;菌落颜色呈乳白色;菌落表面凸起,湿润;菌落圆形、光滑、不透明或半透明。结合生理生化特征和16SrDNA序列分析,JW-4初步鉴定属于根瘤菌属(Rhizobium sp.),JW-5属于中华根瘤菌属(Sinorhizobium sp.),JW-7属于假单胞菌属(Pseudomonas sp.)。以杨树苗作为供试植物,接种Rhizobium sp.JW-4、Sinorhizobium sp.JW-5、Pseudomonas sp.JW-7于盆栽杨树上,结果表明,JW-7对杨树的促生效果最好。苗高和地径分别比CK增长了37.64%和19.44%,鲜重和干重分别比CK增长了65.82%和110.71%。细菌、放线菌、硅酸盐细菌的数量均有显著升高,而真菌的数量都有不同程度的降低。总体看,接种JW-4、JW-5、JW-7均能改善土壤微生物环境,促进植物生长。本试验采用单因素试验法,对解钾培养基中的碳源、氮源和无机盐的种类进行了优化。得出,适合JW-7菌株生长的解钾培养基的最佳碳源为麦芽糖,最适浓度为1%;最佳氮源为蛋白胨,最适浓度为0.2%;最佳无机盐为磷酸氢二钾,最适浓度0.05%。利用单因素试验与正交设计试验相结合的方法,对JW-7菌株的培养条件(装液量、接种量、培养温度、初始pH值、培养时间)进行了优化,结果显示,JW-7菌株的最佳培养条件为:80mL的装液量,7%的接种量,30℃培养温度,7.5初始pH,72h培养时间。本研究结果表明,从杨树根际土壤中筛选到的3株高效解钾菌Rhizobium sp.JW-4、Sinorhizobium sp.JW-5、Pseudomonas sp.JW-7,对杨树生长均有促生作用,并能改善土壤中的微生物环境。
[Abstract]:Well developed poplar industry in China, in the country are widely distributed, the number of varieties complete, poplar plantation area of more than all other countries combined artificial forest area, is an important fast-growing timber tree species in China. But in the recent 50 years, expanding the plantation area, rotation is shortened and the cause of forest soil degradation with this, a decline in productivity, soil fertility decline is closely related to the supply of potassium deficiency is prominent and universal. Potassium is the essential nutrients for plant growth and development. The plant is mainly due to lack of potassium in soil can be the effective potassium rarely, if the soil mineral potassium into effective potassium then, can effectively improve the current situation of potassium deficiency. Potassiumbacteria (potassium bacteria) is separated from the soil, can decompose potassium feldspar aluminosilicate minerals, the solubility of potassium, phosphorus, silicon into soluble state, promote planting Growth and development, improve the yield. As a kind of microbial species and quantity of potassium bacteria in rhizosphere of different plants are different, there is a big difference in potassium solution ability between different kinds of bacteria or different strains, so the screening of high potassium bacterium from the specific plant rhizosphere is particularly important. This study from Yang the rhizosphere soil isolated and screened 3 strains of bacteria, strain JW-4, JW-5 and JW-7, and were identified on poplar growth promoting effect is studied, finally the fermentation conditions of the growth promoting effect of the best strains of JW-7 were optimized for the development and utilization of the future, has important practical significance to solve the lack of potassium China's soil status, the main results are as follows: medium using silicate, the dilution plate method, screening 13 strains of bacteria. Of the 13 strains of shake flask potassium release test, the determination of potassium in efficiency. Screening of 3 strains of bacteria, JW-4, JW-5 and JW-7, the potassium efficiency reached 26.30%, 34.27% and 38.70%. of 3 strains of high potassium bacteria with morphological observation, analysis of physiological and biochemical characteristics and 16SrDNA sequence were identified by.JW-4, JW-5, JW-7 are all bacteria; gram negative bacteria, no spore the milky white color; colony; wetting; colony colony surface bulge, round, smooth, opaque or translucent. Combined with the physiological and biochemical characteristics and 16SrDNA sequence analysis, identification of JW-4 belongs to the genus Rhizobium (Rhizobium sp.), JW-5 belongs to the genus Rhizobium (Sinorhizobium sp. JW-7), belonging to the genus Pseudomonas (Pseudomonas sp.). In poplar seedlings as tested plants inoculated with Rhizobium, sp.JW-4, Sinorhizobium sp.JW-5, Pseudomonas sp.JW-7 on potted poplar, the results show that the growth promoting effect of JW-7 on poplar. The best seedling height and diameter were increased than CK The 37.64% and 19.44%, fresh weight and dry weight were more than the CK growth of 65.82% and 110.71%. of bacteria, actinomycetes, quantity of silicate bacteria was significantly increased, while the number of fungi was decreased in different degree. Overall, JW-4 vaccination, JW-5, JW-7 could improve soil microbial environment, promote the growth of plants the experiment of single factor test, the carbon source medium potassium cultivation, nitrogen sources and inorganic salts were optimized. The suitable strain JW-7 growth solution of potassium culture medium was the best carbon source maltose, the optimal concentration is 1%; the best nitrogen source was peptone, the most optimum concentration was 0.2%; the best inorganic salt as two potassium hydrogen phosphate, the optimum concentration of 0.05%. method by single factor test and orthogonal design combined with the culture conditions of strain JW-7 (liquid volume, inoculation quantity, culture temperature, initial pH, incubation time) were optimized. The results showed that the JW-7 strain The optimal culture condition of liquid filled 80mL, inoculum 7%, 30 C 7.5 of the initial pH, culture temperature, culture time of 72h. The results of this study showed that from poplar rhizosphere soil screened 3 strains of bacteria, Rhizobium sp.JW-4, Sinorhizobium sp.JW-5, Pseudomonas sp.JW-7, has a promoting effect on the growth of poplar, and can improve the microorganism in the soil environment.

【学位授予单位】：南京林业大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：S792.11;S714.3

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