酸性土壤中决明属牧草高效根瘤菌的分离及筛选

为提高豆科决明属（Chamaecrista spp.）牧草的结瘤能力和固氮效率，促进决明属牧草在酸性土壤中的应用及推广，本研究以圆叶决明（Chamaecrista rotundifolia）和羽叶决明（Chamaecrasta nictitans）为试验材料，通过分离、纯化、nodA基因鉴定等方法，从酸性土壤里决明属牧草的根瘤中分离到10株候选根瘤菌株系。16S rDNA测序及系统发育树分析表明，这10株根瘤菌均属于慢生型根瘤菌。回接试验表明，上述10株根瘤菌均能与圆叶决明共生，形成根瘤。与不接种的对照相比，其固氮酶活性为0.08~4.65 μmol·g^-1·h^-1，植株干重、SPAD值和氮含量分别提高了99.17%~372.14%，399.27%~789.05%，235.00%~1043.33%。其中，4株根瘤菌TXR2，TXN1，WYSR1，JYN6对圆叶决明氮营养贡献最大，并且TXN1与宿主共生形成的根瘤数目最多，而JYN6的固氮酶活性最高。说明本研究分离鉴定到4株决明高效根瘤菌，具有较好的应用前景。     

黔东南土鸡不同醒抱方法的效果研究

为研究黔东南土鸡的醒抱方法，将刚进入抱窝状态的母鸡分成4个组，分别采用4种不同的醒抱方法进行试验。I组自然醒抱；Ⅱ组自由活动，加喂异烟肼；Ⅲ组采取隔离；lV组采取隔离，加喂异烟肼。结果表明：（1）醒抱时间：Ⅰ组、Ⅱ组和Ⅲ组、Ⅳ组比较，均差异极显著（P〈0．01）；Ⅲ组和Ⅳ组比较，差异不显著（P〉0．05）。（2）复产时...     

‘秦美’猕猴桃贮藏期病原真菌的鉴定

以‘秦美’猕猴桃为试材,分离纯化在贮藏过程中引起腐烂的主要病原真菌。采用形态学观察及核糖体rDNA-ITS(Internal transcribed spacer)区序列分析法进行鉴定。结果表明:从腐烂猕猴桃中共分离出5株致病菌,对ITS区序列测序结果经GenBank数据库BLAST比对,A的ITS序列与Trichothecium roseum(EU552162.1)同一分支,支持率达100%;B的ITS序列与Fusarium tricinctum(AB587078.1)同一分支,支持率达99%;C的ITS序列与Penicillium expansum(AF330635.1)同一分支,支持率达99%;D的ITS序列与Colletotrichum boninense(KF819619.1)同一分支,支持率达99%;E的ITS序列与Botrytis elliptica(KJ638600.1)同一分支,支持率达100%。由形态学及ITS区序列分析,构建系统发育树,最终鉴定A为粉红聚端孢(Trichothecium roseum),B为镰刀菌属(Fusarium tricinctum),C为扩展青霉(Penicillium expansum),D为炭疽病菌(Colletotrichum boninense),E为灰葡萄孢(Botrytis cinerea)。5种病原真菌中灰葡萄孢为主要致病菌。     

葡萄枝叶自然青贮中优选乳酸菌的分离与鉴定

本研究旨在对葡萄枝叶青贮饲料中天然附着优势乳酸菌进行分离培养和鉴定,为葡萄枝叶资源的饲料化利用提供可靠的乳酸菌资源。利用分子生物学鉴定法(16S rDNA序列分析)与传统的微生物鉴定法对分离出的乳酸菌进行鉴定,最终得到5株乳酸菌菌株,其中Q1菌株鉴定为肠膜明串珠菌(Leuconostoc mesenterica),Q2和Q5菌株鉴定为屎肠球菌(Enterococcus faecium),Q3菌株鉴定为铅黄色肠球菌(Enterococcus casseliflavus),Q4菌株鉴定为海氏肠球菌(Enterococcus hirae)。所筛选出的乳酸菌除L.mesenterica在pH为9时不能生长,其余菌株均能在pH 3～9,4℃～45℃,3%和6.5% NaCl浓度环境下生长;其中E.hirae菌株在培养至24 h后其菌液pH可达到4.11,OD值为1.42,表现出最强的生长及产酸能力。     

猪源乳酸杆菌的分离鉴定及生物学特性分析

乳酸杆菌制剂可以替代抗生素,用于预防和治疗细菌性腹泻。为获取可作为微生态制剂的候选菌株,从健康仔猪肠道分离到5株乳酸杆菌,经抑菌试验、生长曲线测定、耐酸、耐胆盐、耐胰酶试验等,筛选到1株对大肠杆菌、沙门氏菌、金黄色葡萄球菌等致病菌有较好的抑制作用,对低pH值、高胆盐、胰酶均有一定耐受能力的乳酸杆菌,命名为LY7。经PCR鉴定,该菌株为约氏乳杆菌。     

Hybridization among Epimedium (Berberidaceae) species native to China

The hybridization of fourteen plant populations belonging to seven Epimedium species native to China was studied by self-cross, infra-population cross, inter-population cross within species, and interspecific cross. Self-pollination studies on nine populations indicated high incompatibility; capsule-set rates were higher than zero in only three (4.61–6.76%). Interspecific cross-pollinations demonstrated high crossabilities in most cross combination (15.38–92.44% capsule-set rate), and the F₁ seeds possessed high germination rates (>20%). The F₁ hybrids of three interspecific cross combinations were raised to maturity. The morphology, karyomorphology of somatic cells, and pollen mother cell (PMC) meiosis of these F₁ plants revealed that they were all highly fertile (>76.10% in pollen viability), that there were few structural differences in chromosomes among species, and that most PMCs had 6 bivalents at MI. Abnormal chromosomal behaviors occurred in a minority, including chromosome bridges, unequal segregation of chromosome number, lagging chromosomes, and micronuclei. A series of experimental crosses provided strong evidence for an outbreeding system and a weak internal barrier to hybridizations in the taxa studied.     

适于AFLP分析的澳洲坚果DNA提取方法

利用SDS法和改良CTAB法对澳洲坚果两个品种的基因组DNA进行提取试验,结果表明:SDS法与改良CTAB法提取的基因组DNA完整性都比较好,但SDS法获得的DNA含有较多杂质,不能被限制性内切酶消化,改良CTAB法提取的基因组DNA可以完全酶切,DNA质量符合AFLP分析的要求。     

新造林中的防火隔离带建设

新造林中防火隔离带分为天然防火隔离带;植物防火隔离带;防火林道,人工防火线等4种。在具体布设上则分为林中防火、林线防火、山脊防火、境界防火、铁路沿线、林区房屋隔离带6种。     

小麦秸秆中生化他感化合物的研究概况

自然界存在着生化他感现象。本文对小麦秸秆生化他感现象、生化他感化合物和化合物的提取、分离、鉴定以及生测、影响其分泌的因素进行了较详细的阐述，并对国内外研究现状和应用前景进行了介绍。     

Anthropogenic determinants of primate and carnivore local extinctions in a fragmented forest landscape of southern Amazonia

Habitat fragmentation has been shown to influence the abundance, movements and persistence of many species. Here, we examine the effects of forest patch and landscape metrics, and levels of forest disturbance on the patterns of local extinction of five primate and 14 carnivore species within 129 forest patches in a highly fragmented forest landscape of southern Brazilian Amazonia. Classic habitat area effects were the strongest predictors of species persistence, explaining between 42% and 55% of the overall variation in primate and carnivore species richness. Logistic regression models showed that anthropogenic disturbance, including surface wildfires, timber extraction and hunting pressure, had detrimental effects on the persistence of some species over and above those of fragment size. Different species ranged in their responses from highly sensitive to highly tolerant to forest fragmentation. Patterns of local extinction documented here were by no means chance events, and the nestedness of the overall species-by-site matrix was highly nonrandom in terms of the sets of species extirpated from the most to the least species-rich forest patches.