绿肥翻压年限对植烟土壤微生物量C、N和土壤C、N的影响

通过3年田间定位试验,研究连年翻压绿肥对植烟土壤微生物量C、N和土壤C、N的影响,结果表明:连年翻压绿肥能够显著提高土壤微生物量C、N含量以及土壤C、N含量,这种提高的趋势随着翻压年限的增加而增加。在烟株整个生育期,植烟土壤翻压绿肥3年后与对照相比,土壤微生物量C、N含量分别提高了30.96%～67.13%、22.96%～145.07%,土壤有机碳、全N、碱解氮含量分别提高了27.84%～53.77%、8.85%～40.95%、11.62%～20.94%,表明翻压绿肥后土壤生物过程活跃,有利于土壤有机物质的转化和烤烟正常生长所需的营养供应。相关分析表明,土壤微生物量C、N在大多数生育时期均与土壤C、N呈显著或极显著正相关。     

尿素包合法纯化ARA的研究

为了提高微生物油脂中花生四烯酸的含量,采用尿素包合法,利用正交试验确定了尿素包合反应的最佳条件,并采用气相色谱分析花生四烯酸含量。试验得出最佳的工艺条件为:尿素:脂肪酸为4:1(W:W)、脂肪酸:乙醇为1:12(W:W)、包合温度为-15℃和包合时间为12h,微生物油脂中花生四烯酸含量为36.84%。通过方差分析和验证试验,数学模型可靠并且拟和较好。     

土壤微生物多样性及发展前景

土壤微生物是土壤的重要组成部分,其群落结构多样性及变化在一定程度上反映了土壤的质量,是土壤生态系统稳定性的重要指示因子。从土壤微生物多样性的定义、农田影响因素、生态功能方面阐述了土壤微生物多样性的作用,并探讨其发展前景。     

秸秆生物反应堆技术的应用对设施黄瓜土壤微生物的影响

通过引进微生物制剂对设施黄瓜枯萎病进行生态调控研究。结果表明,在黄瓜生长前期和中期,秸秆生物反应堆处理土壤微生物结构由易发病的真菌型向有利于蔬菜生长的细菌型转变,即真菌数量几乎维持不变,但细菌和放线菌数量增加较快,后期则变化不大。使用秸秆生物反应堆技术,可提高土壤微生物对碳源的利用率,使土壤生理代谢活力增强,改变土壤营养条件,使其朝着有利于作物生长的方向进行。     

覆膜条件下小麦和玉米根系化感作用对土壤微生物的影响

采用稀释平板涂布法对西北旱地覆膜条件下小麦和玉米根区和根外土壤中可培养细菌、真菌、放线菌的数量进行测定,并将其与常规对照进行比较。结果表明,覆膜模式下小麦和玉米根区土壤细菌、真菌和放线菌数量均高于常规处理,增率均为正值,小麦根系利于根区与根外土壤细菌和放线菌数量的生长,玉米根系化感作用利于根区土壤真菌数量的增加;玉米和小麦根区形成的微环境有利于土壤细菌和真菌数量的增加,即R/B值大于1,玉米的根系化感作用能够强化根区与根外土壤细菌和真菌数量的差异,即R/B值较高;玉米根区土壤微环境较小麦更利于土壤放线菌生长。小麦和玉米对土壤中可培养微生物数量的化感效应表现不同,覆膜模式下小麦利于土壤细菌和放线菌数量的增加,玉米根系的化感效应利于根区土壤真菌数量增加。玉米根区放线菌数量高于根外,小麦与之相反。     

A comparative study on the rumen microbial populations,hydrolytic enzyme activities and dry matter degradability between different species of ruminant

A comparative study among Korean native cow (Hanwoo), Holstein dairy cow, Korean native goat and crossbred sheep on the population and marker concentration of ruminal microbes, the activities of carboxymethylcellulase (CMCase), xylanase and amylase, and in situ dry matter (DM) degradability were conducted. Twelve ruminally cannulated animals, three of each species, were used. Animals were fed the same diet containing 40% formula feed and 60% rice straw at the level of 2.5% of body weight. Total viable microbial populations in the rumen fluid were significantly (P < 0.01) greater for bacteria and fungi in goat than those of Holstein. The protozoan population among ruminant species was the reverse from that of bacteria. The concentrations of 2,6‐diaminopimelic acid and chitin as markers for bacteria and fungi in the rumen fluid, respectively, were highest in goat, which is in accordance with the above population data. The concentration of aminoethylphosphonic acid as marker of protozoa was highest in Hanwoo and lowest in sheep (P < 0.01). Goat had the highest (P < 0.01) activities of all the enzymes investigated among ruminants. In situ effective degradation of the DM of rice straw was approximately 19% higher in the rumen of goat compared with other animals.     

Dynamic Changes of Microbial Community for Degradation of Lignocellulose

Dynamic changes of a microbial community for lignocellulose degradation were explored in details. Community composition and development were investigated by the means of denaturing gradient gel electrophoresis （DGGE）, and results showed that the microbial community was constituted of 14 kinds of bacteria and presented the fluctuation in some degrees with fermentation. Furthmore, the result of cluster analysis of DGGE pattern was accordant with growth curve, and the degradation process was divided into three stages： initial stage （0-12 h）, intermediate stage （24-144 h） and end stage （144-216 h）.     

污泥好氧堆肥及桉树施肥试验研究

研究生活污泥腐熟菌株的生长条件,堆肥接种剂L201在pH 7.7及温度58～65℃时生长较好,堆肥接种剂L301的最适生长温度是52～55℃;仓式好氧堆肥的前期通气量较少,中、后期通气量较多。施用有机肥LC301可以加快桉树生长。     

重金属胁迫下大薸根际微生物的变化

为了研究重金属对大薸根际微生物区系及氮循环细菌生理类群的影响,采用水培养方法,用4种重金属离子(Hg2+、Pb2+、Cd2+和Cr6+),在不同浓度下对大薸进行胁迫培养。结果表明,Hg2+、Pb2+、Cd2+和Cr6+对大薸根际微生物的影响,随微生物区系或生理类群和重金属的胁迫浓度不同而不同,Hg2+对放线菌、细菌、真菌的毒性最强,Pb2+次之。3类微生物对4种重金属的敏感性表现为放线菌细菌真菌。在4种不同重金属和不同浓度胁迫下,氨化细菌、硝化细菌、亚硝化细菌和反硝化细菌的变化有一定差异。     

三峡库区云阳县三种类型马尾松林微生物区系及优势种群分析Ⅱ.林地空气、叶面和树皮表面

为探讨马尾松不同类型林地地上部微生物区系及优势种群及其季节性变化,对三峡库区云阳县马尾松近熟龄天然林、中龄天然林和人工林林地空气、叶面和树皮表面等地上部的可培养细菌和真菌进行了分析。结果表明,空气、叶面和树皮表面的真菌、细菌两大类微生物数量四季变化趋势基本一致,夏季和秋季的数量多于冬季和春季,中龄天然林的两大类微生物数量最大且四季变化亦最大;优势种群的种类和数量随季节和林地类型不同而有所变化。人工林空气中可培养真菌种类秋、冬、春、夏分别有4、3、4、3种,近熟龄天然林和中龄天然林四季中均为3种;优势种群多