青海高原土壤拮抗性放线菌的生态分布

ECOLOGICAL DISTRIBUTION OF SOIL ANTIMICROBIAL ACTINOMYCETES OF THE QINGHAI PLATEAU

采用琼脂块法测定了分离自青海高原不同生态环境下的 1 007株代表性放线菌的拮抗性.结果表明:①供试菌中对大肠杆菌、金黄色葡萄球菌、假丝酵母、青霉、辣椒疫霉、西瓜枯萎菌、棉花枯萎菌及黄瓜枯萎菌有拮抗性的放线菌占供试菌总数的比率分别为 9. 1%、27. 2%、2. 1%、2. 6%、13. 8%、10. 1%、7. 1%及 7. 4%;在青海高原(西部)土壤的拮抗性放线菌中,抗细菌放线菌多于抗真菌放线菌,抗G+细菌的放线菌多于抗G-细菌放线菌,抗丝状真菌放线菌多于抗单细胞真菌放线菌.②耕作土壤中,拮抗性放线菌株数占放线菌总株数的百分率 (拮抗菌百分率 )是自然土壤的3. 5倍,且耕作土壤拮抗菌百分率按菜地(71. 7% ) >粮田(40. 6% ) >绿肥地(32. 8% ) >果园(25. 0% )的顺序排列.旱地土壤拮抗菌百分率明显高于水地.③不同类型土壤拮抗菌百分率均不同,且不同类型土壤拮抗菌百分率按黑钙土>栗钙土>灰钙土>砂土的顺序排列.④拮抗性放线菌的数量、拮抗菌百分率与土壤有机质、全氮、碱解氮、全磷及磷酸酶活性有关.其中有机质和全氮与拮抗性放线菌株数和拮抗菌百分率的相关性达极显著水平 (P<0. 01).抗细菌与抗真菌拮抗性放线菌的出现频率与土壤有机质、全氮及放线菌总数量的相关性分别达到了极显著(P<0. 01)与显著水平(P<0. 05),且土?

The antimicrobial actions of 1 007 representative strains were measured by method of agar block. The results indicated that: ① 9.1%,27.2%, 2.1%,2.6%, 13.8%, 10.1%, 7.1%, and 7.4% of the tested strains had antimicrobial activities against Escherichia coli, Staphylococcus aureus, Candida tropicalis, Penicillium sp., Phytophthora capsici, Fusarium oxysporum f.sp. niveum , Fusarium oxysporum f.sp. vasinfectum, and Fusarium oxysporum f.sp. cucumerinum,respectively, which illustrated that there were more antimicrobial actinomycetes against bacteria than fungi, more against G + bacteria than G - bacteria, and more against filament fungi than single cell fungi in the western Qinghai Plateau. ② The percentage of antimicrobial actinomycetes in cultivated soil was three and half times of natural soil, and the percentage in cultivated soil showed in the following order: vegetable field (71.7%)>grain field (40.6%)>green manure field (32.8%)>orchard field (25.0%). The percentage of antimicrobial actinomycetes in non-irrigated field was larger than that in irrigated field. ③ The percentage of antimicrobial actinomycetes in different soil types was different, arranging in the following order: chernozem>Castanozem>Sierozem>sandy soil. ④ The number and percentage of antimicrobial actinomycetes were related with organic matters, total N, total P, available N and phosphatase in soil. Correlated coefficient between soil organic matter and the number of antimicrobial actinomycetes, or soil organic matter and the percentage of antimicrobial actinomycete, or soil total N and the number of antimicrobial actinomycetes, or soil total N and the percentage of antimicrobial actinomycetes reached very remarkable level(P< 0.01). Correlated coefficient between soil organic matter, soil total N, or total count of actinomycetes and appearing rate of antimicrobial actinomycete against bacteria(or fungi)got very remarkable level respectively(P<0.01)or remarkable level(P< 0.05). The content of organic, matter total P, and total N had a larger effect on the percentage of antimicrobial actinomycetes against bacteria than that of fungi. Tab 7, Ref 10