【作者】 刘青海；

【导师】 姚拓；

【作者基本信息】 甘肃农业大学 ， 草业科学， 2011， 硕士

【摘要】 利用钼锑抗比色法、Salkowski比色法和平板对峙等方法研究了6株溶磷菌(Jm170、Jm92、Lx191、Lx22、Jx59、Lx81)与4株固氮菌(W5、N4、G、S11)互作效应,测定了各菌株组合对环境因素的响应、溶磷、分泌植物生长激素(IAA)、拮抗植物病原真菌等特性。同时,利用盆栽试验测定单一及复合菌剂对苜蓿(Medicago sativa L.)生长的影响,结果表明:1.供试的6株溶磷菌和4株固氮菌间无拮抗现象,可以混合培养。与各菌株单独培养相比,溶磷菌和固氮菌混合培养对温度、pH值和盐分等环境因子有更广适应性。2.与各菌株单独培养相比,溶磷菌和固氮菌两两混合培养时,大多数混合体系溶磷能力增强,其中Jx59+G组合、Lx22+G组合和Jm92+G组合溶磷量分别为306.26 mg/L、291.43 mg/L和235.22 mg/L,较两菌株单独培养之和增加了分别增加了42.28%、46.91%、52.02%;少数混合体系溶磷能力减弱,其中Lx191+W5组合、Jx59+N4组合、Jm92+S11组合较溶磷菌株单独培养时分别降低44.88%、32.52%、16.28%。3.溶磷菌和固氮菌多菌株混合组合中,Jm92+Lx22+G组合溶磷量最高,为330.42 mg/L,与Jm92+G组合和Lx22+G组合相比增加40.47%和13.38%,Jm92+Lx22++S11+G组合的溶磷量也较高,为322.55 mg/L,与Jm92+Lx22+G组合相比下降2.43%。4.大部分溶磷菌和固氮菌组合混合培养液有机酸含量较单独培养显著升高;溶磷菌单独培养时,溶磷量、pH值和有机酸含量存在显著相关性,但混合培养时组合体系的溶磷量、pH值和有机酸含量相关性较弱。5.溶磷菌和固氮菌单独培养时,固氮菌G菌株分泌生长激素的能力最强,为37.34μg/ml;溶磷菌和固氮菌两两组合培养时,Lx22+G和Jm92+N4组合分泌生长激素量最多的,分别为36.71μg/ml和33.19μg/ml,Jm92+N4、Lx191+N4和Jx59+N4组合均较组合中两菌株单独培养之和提高428.81%、162.5%和7.89%。Lx191+Lx22+G组合分泌生长激素量最高,为41.15μg/ml。6.溶磷菌和固氮菌两两混合培养的48个组合中,只有9个组合对辣椒立枯丝核菌、西瓜尖镰孢菌和棉花立枯病菌有抑制作用,Jm92+N4对三种病原菌的抑菌率最高,分别为80.38%、79.06%和75.12%。7.与试管斜面培养法、蒸馏水保存法相比,真空冷冻干燥法保存的溶磷菌溶磷能力下降较少,建议长时间保存菌种使用该方法。8.单菌株及混合菌株组合处理与对照相比均可提高苜蓿株高、根长、根瘤数、地上植物量和地下植物量,与单菌株接种处理相比,混合接种处理促生效果更好,其中Jm92+Lx22+S11+G处理促生效果最好,地上植物量较对照提高121.21%,其次为Jm92+Lx22+G处理和Jm92+Lx22+N4+S11处理,地上植物量较对照提高69.24%和60.15%9.混合菌株较单菌株能更好的促进苜蓿对氮、磷的吸收,Jm92+Lx22+S11+G处理最好,苜蓿含氮量和含磷量较对照有显著提高,其次为Jm92+Lx22+G处理和Jm92+Lx22+N4+S11处理,这三种组合有望成为苜蓿新的根际接种剂或菌肥。更多还原

【Abstract】 Interaction effect of six phosphate solubilizing bacteria (Jm170, Jm92, Lx191, Lx22, Jx59, and Lx81) and four nitrogen-fixing bacteria (W5, N4, G, S11) were studied by using Molybdenum blue, Salkowski colorimetry and Plate duel culture. Characteristics of responsing to environmental factors, solubilizing phosphorus, secreting indole acetic acid (IAA) and antagonizing plant pathogenic fungi were tested. The effects of the growth of alfalfa (Medicago sativa L.) under the treatments of single strain and mixed strains inoculum were tested based on pot culture as well. The results showed as follow:1. There was no antagonism among six phosphate solubilizing strains and four nitrogen-fixing bacteria strains, so they can be cultured mixed. Compare with single strain, mixed strains of phosphate solubilizing bacteria and nitrogen-fixing bacteria had a wider range of adaptation, for instance, the culture temperature, the pH, the salinity.2. The phosphorus-solubilizing ability of most mixed bacteria strains was significantly increased compared with single strain. The phosphate-solubilization capacity of the treatments of Jx59+G, Lx22+G and Jm92+G were 306.26 mg/L, 291.43 mg/L and 235.22 mg/L, which were higher than the sum of the two strains cultured alone by enhancing 42.28%, 46.91% and 52.02% respectively. The phosphorus-solubilizing ability of a small number of mixed bacteria strains significantly decreased compared with single strain. The phosphorus-solubilizing capacity of the treatments of Lx191+W5, Jx59+N4 and Jm92+S11 were lower than bacteria strains cultured alone by reducing 44.88%, 32.52% and 16.28% respectively.3. The phosphorus-solubilizing ability of treatment of Jm92+Lx22+G was the highest in the mixed strains of phosphate-solubilizing bacteria and nitrogen-fixing bacteria, which was 330.42 mg/L, by enhaning 40.47% and 13.38% compared with the treatments of Jm92+G and Lx22+G respectively. The phosphorus-solubilizing ability of the treatment of Jm92+Lx22++S11+G was also high, which was 322.55 mg/L, by decreasing 2.43% compared with the treatments of Jm92+Lx22+G.4. The organic acids content of most mixed bacteria strains was significantly increased compared with the single strain. The phosphorus-solubilizing capacity was related to the pH and the organic acids content prominently, when phosphate solubilizing bacteria cultured alone. But the phosphorus-solubilizing capacity was hardly related to the pH and the organic acids content, when phosphate solubilizing bacteria and nitrogen-fixing bacteria cultured mixed.5. Strain G had the most active ability to produce IAA, which up to 37.34μg /ml, when phosphate solubilizing bacteria and nitrogen-fixing bacteria cultured alone. Treatments of Lx22+G and Jm92+N4 had a stronger ability to produce IAA than other treatments, which was up to 36.71μg /ml and 33.19μg /ml when phosphate solubilizing bacteria and nitrogen-fixing bacteria cultured mixed. The ability to produce IAA of treatments of Jm92+N4, Lx191+N4 and Jm92+N4 were higher than the sum of the two strains cultured alone by enhancing 428.81%, 162.5% and 7.89% respectively. Among all the treatments, Lx191+Lx22+G had the strongest ability to produce IAA, which was 41.15μg/ml.6. Among the 48 treatments of phosphate solubilizing bacteria and nitrogen-fixing bacteria cultured mixed, only 9 treatments possessed the positive antagonism, which antagonized against Rhizoctonia solani (pepper strain), Fusarium oxysporum f. Niveum and Rhizoctonia solani (cotton strain). Inhibition ratio of treatment of Jm92+N4, which antagonize against three plant pathogenic fungi, was the highest, 80.38%, 79.06% and 75.12% respectively.7. The phosphorus-solubilizing ability of phosphate solubilizing bacteria preserved by the method of Vacuum Freeze-drying Preservation was stronger than the method of Periodic Transplantation Preservation and Distilled Water Preservation. It was a better choice to preserve phosphate solubilizing bacteria for the long time by the Freeze-drying Preservation.8. Single and compound inoculum treatments had an obvious effect on the height, the root length, the nodule number, the above-ground biomass and the underground biomass of alfalfa, compared with control. Compound inoculum treatment had a better effect than single inoculum treatment on the quality of alfalfa growth. The treatment of Jm92+Lx22+S11+G had more benefit than other treatments, and the above-ground biomass increased 121.21% compared with control. Treatments of Jm92+Lx22+G and Jm92+Lx22+N4+S11 also had a better effect so that the above-ground biomass increased 69.24% and 60.15% respectively compared with control. 9. Mixed bacteria strains were better than single bacteria strain on the absorption of phosphorus and nitrogen on alfalfa, among which the treatment of Jm92+Lx22+G had the best effect. Nitrogen and phosphorus content of alfalfa increased than control, among which the treatments of Jm92+Lx22+G and Jm92+Lx22+N4+S11 had better effect also. These three mixed strains were expected to become the new rhizosphere inoculant or the biofertilizer of alfalfa.更多还原