土壤嗜铁细菌C19的筛选、分子鉴定及其对炭疽菌和镰刀菌的拮抗作用

利用LB液体培养基进行生物富集,采用CAS(Chrome Azurol S)检测平板法.从海南岛橡胶树等作物根际土壤中分离获得43个产嗜铁索细菌菌株.通过室内平板对峙培养法研究其中嗜铁能力较强的菌株C19对12个常见炭疽菌和镰刀菌的拮抗作用,结果表明.该菌株对Fusarium solani等9个菌株有不同程度的拮抗作用,显示该菌株具有较好的生防潜能.扩增菌株C19的16S rDNA序列,序列测定结果显示,该片段长度为1 525 bp,经Blastn搜索进行序列比对.该细菌为洋葱伯克霍尔德氏菌(Burkholderia cepacia).     

水稻小球菌核菌无性世代分生孢子双曲孢菌(Nakataea sigmoidea)的发现及产孢条件研究

报道了黑龙江省水稻小球菌核菌无性世代的分生孢子双曲孢属 (Nakataea sigmoidea Hara) ,并对其人工培养条件进行了初步探讨。结果表明 ,在黑暗条件下 ,不同的营养条件、环境条件及培养方式病原菌均不能产生分生孢子 ;在自然光条件下 ,病原菌的菌核和菌丝在水琼脂培养基上均可产生分生孢子。生长物质和微量元素均不能促进孢子产生。C/ N对菌核萌发直接产生分生孢子有影响 ,其中 C/ N为 10 / 1时产孢率最高 ,达 5 4 .2 3%。     

培养条件对枯草芽胞杆菌TU100生长和产生抗菌物质的影响

以在油菜根际高效定殖的枯草芽孢杆菌(Bacillus subtilis)TU100为材料,研究其主要抗菌物质的代谢条件。证明其主要拮抗物质属胞外分泌型,释放到培养液中,对油菜菌核病菌(Sclerotinia sclerotiorum)具有较高的抑制活性。TU100在28-30℃生长旺盛,产抗菌物质也较多;培养48h数量达最大值,培养72h抗菌物质的产生量达高峰。培养液的初始pH值6-8有利于TU100增殖,抗菌物质活性也最强;通气良好的条件下TU100菌株生长好、产抗菌物质量多;培养基C/N比对菌株生长也有重要影响,C/N比为15时有利于TU100生长以及抗菌物质的积累。     

氮肥配施生物炭对土壤性状及春玉米根系特性的影响

为探究生物炭在土壤氮素分布以及对根系氮素吸收利用与产量形成中所产生的影响,开展两年(2019-2020)定点试验。试验以先玉335为供试材料,采用裂区试验设计,以氮肥为主区,300 kg/hm²(N300)、150 kg/hm²(N150)、不施氮肥(N0);以生物炭为副区,不施生物炭(C0)、8 t/hm²(C8)、16 t/hm²(C16)、24 t/hm²(C24)。结果表明,在0～15 cm土层内,C8N0、C16N0、C24N0处理组合的有机碳在2019年和2020年较C0N0处理组合分别增加16.27%～31.52%和7.27%～35.57%。在2019年和2020年,C8N150、C16N150、C24N150处理组合较C0N150处理组合的根长分别提升11.22%～51.18%和6.32%～46.17%,产量分别提升10.70%～23.55%和4.77%～22.68%。综上,生物炭施炭量在24 t/hm²时,施氮肥150 kg/hm²对土壤有机质积累分布和根系的发育状况达到最佳状态。     

不同肥水供给模式对高蛋白大豆干物质累积、氮素代谢、产量及品质的影响

为探索高蛋白大豆高产优质生产适宜肥水协同供给模式,以高蛋白驻豆19为试验材料,采用不同施氮量与灌水量进行田间裂区试验,设置3个施氮量水平,N0(不施氮肥)、N1(60 kg·hm^-2)、N2(120 kg·hm^-2);3个灌水水平,W0(不灌水,自然降雨)、W1灌水量(1 500 m³·hm^-2)、W2灌水量(3 000 m³·hm^-2),研究了高蛋白大豆干物质和氮素累积与分配、氮素利用及品质对肥水协同供给的响应。结果表明：同一灌水量条件下,干物质积累分配量呈现豆荚>茎>叶,2020年豆荚分配占比53.65%～69.00%,2021年豆荚分配占比36.25%～52.15%;同一施氮条件下,随着灌水量的增加,鼓粒期干物质累积量呈逐渐升高趋势,在施氮N1条件下,灌水量为W2时,干物质累积量较自然降水W0、灌水量处理W1分别提高了56.55%和11.67%;不同灌水量条件下,提高施氮量反而降低了氮素吸收效率、氮素利用效率、氮肥农学效率、氮肥偏生产力,...     

生物炭施用对早稻产量形成的影响

为探明生物炭施用对早稻产量形成的影响,以中早39为材料,于2015年和2016年早季在湖南省浏阳市永安镇开展大田试验,在不同施氮水平下(N0,0 kg N/hm~2;N1,90 kg/hm~2;N2,150 kg N/hm~2)对施炭(C1,20 t/hm~2)和不施炭(C0,0 t/hm~2)处理早稻的产量、产量构成、干物质生产和收获指数进行了比较。结果表明,除2015年N1水平外,C1处理的产量均低于C0处理,其中,2016年C1处理的平均产量比C0处理低12.85%;2015年和2016年C1处理的千粒重分别比C0处理低2.46%~4.12%和2.55%~3.76%;齐穗后C1处理干物质生产量高于C0处理,但其收获指数低于C0处理,2015年和2016年C1处理与C0处理的收获指数最大相差5.33个和4.00个百分点。由此可见,施用生物炭显著降低了早稻千粒重和收获指数,进而导致早稻减产。     

种植年限对胶园土壤剖面有机碳分布特征的影响

通过剖面直接实测法,研究幼树期(4 a)、旺产期(12 a和19 a)3种不同树龄橡胶林土壤有机碳变化特征及其与土壤pH、全氮、C/N比的相关关系。结果表明:(1)4、12、19 a橡胶林土壤有机碳含量均随着土层深度的增加而降低;3个树龄橡胶林土壤有机碳总体大小顺序为12 a>4 a>19 a。(2)橡胶林土壤呈酸性反应,且土壤剖面有机碳含量均随深度呈下降趋势,而土壤pH随深度呈上升趋势。土壤不同层次有机碳含量与pH呈显著负相关(R2≥0.708 8)。(3)不同树龄橡胶林土壤有机碳与全氮之间均呈显著的线性正相关,土壤C/N比为8.19~16.49,有利于有机质矿化过程中养分的释放。橡胶林土壤C/N比随树龄的增长不断下降,说明树龄大小对土壤碳氮含量在土壤剖面垂直分布上有一定的影响。     

水稻超高产栽培的双层源库关系的研究

 为研究光合生产与矿质营养的双层源库关系，设计了窄密沟与平作两种土壤环境，无N、150 kg N/hm²、225 kg N/hm²三个N肥水平的处理，研究了光合生产、矿质营养和两者的双层源库关系。结果表明：根系发育与分布在双层源库间起着承上启下的作用。土壤水分环境改善可同步促进根系发育和下伸、土壤N矿化和植株N吸收。植株吸收N能力的增强，使施N吸收效率提高；但要提高施用N的产量效率，还需提高吸收N的利用效率。为此，改善地上部群体配置，对光合生产与矿质营养的双层源库关系协调发展有重要意义。     

不同饼肥碳氮比发酵液对香蕉枯萎病及土壤微生物群落功能多样性的影响

为探明3种饼肥不同碳氮比发酵液对香蕉枯萎病及土壤微生物群落功能多样性的影响,室内盆栽条件下,研究了菜籽饼、豆饼和花生饼3种饼肥的不同碳氮比发酵液对香蕉枯萎病的防控效果,并采用Biolog微平板技术和T-RFLP方法分别研究了不同处理土壤微生物群落多样性和优势种群的差异。结果表明,施用饼肥发酵液能显著降低土壤尖孢镰刀菌数量;在香蕉移栽60 d时,C/N为25∶1的菜籽饼和豆饼发酵处理的防病效果分别为67.25%和66.51%,显著高于相同碳氮比的花生饼发酵处理;Biolog结果显示,3种饼肥发酵处理的根际土壤微生物群落AWCD均表现为:CK15∶1(C/N)20∶1(C/N)25∶1(C/N),Mc Intosh指数随碳氮比的增加而显著降低;PCA分析表明,3种饼肥的25∶1(C/N)发酵液处理的土壤微生物群落碳源利用能力相近,且均与对照处理明显不同。分析优势种群发现,对尖孢镰刀菌具有拮抗作用的芽胞菌和链霉菌等普遍存在于发酵液处理中,且防病效果越佳的处理,所含有的微生物优势种群的多样性越明显。菜籽饼发酵液C/N为15∶1~25∶1时,防病效果无显著差异,豆饼和花生饼发酵液的最佳C/N为25∶1;施用饼肥发酵液可以促进植株生长,降低枯萎病病情指数,改善土壤微生物功能多样性。     

不同氮源对文心兰生长发育与植株中矿质元素含量的影响

在施氮总量相同的条件下,比较NO3--N、NH4+-N的比例分别为1∶0、2∶1、4∶1、6∶1、10∶1和0∶1时对文心兰“黄金2号”生长发育的影响。试验结果表明,文心兰“黄金2号”苗期和花期生长发育的最佳N源是NO3--N/NH4+-N为10∶1,其次为6∶1;随着NO3--N比例的增加,文心兰植株体内N、K含量呈上升趋势,NH4+-N 利于根部对Ca,Mg素的吸收,NO3--N 利于茎部对Ca,Mg的吸收;在文心兰整个生长发育阶段,中苗期至花芽分化期对N,K元素的吸收最旺,对P,Ca,Mg整体吸收量     

同源重组法构建枯草芽孢杆菌dhbC基因缺失突变株和回复株

为了验证dhbC基因的功能,以质粒pEGFP-NI为模板,通过PCR扩增获得新霉素抗性基因(neo~r)DNA片段,构建重组质粒pMD18-neo,电击转化法将pMD18-neo导入枯草芽孢杆菌Bacillus subtilis CAS15感受态细胞中,使neo'基因片段与dhbC基因片段发生置换,获得dhbC基因缺失突变株.再通过电击转化将dhbC 基因全长编码序列导入dhbC基因缺失突变株CAS15 dhbC-del,获得dhbC基因回复株CAS15 dhbC-com.经CAS平板法检测表明,CAS15 dhbC-del不能产生橘黄色晕圈,而CAS15 dhbC-tom产生与CAS一致的橘黄色晕圈,证明了dhbC基因与嗜铁索的合成密切相关.     

一株产铁载体橡胶树拮抗细菌的分离鉴定及耐药性分析

从橡胶树根部分离到一株拮抗细菌Czk1,该菌株在铬天青(CAS)检测平板上产生较大的桔黄色显色圈,具较强的铁载体产生能力.对其进行生理生化鉴定、16S rDNA序列分析,测定7种常见抗生素的抗性.结合该菌菌落、菌体特征,生理生化指标及16S rDNA序列分析,鉴定该内生菌为枯草芽孢杆菌(Bacillus subtilis),该菌对四环素、红霉素、氨苄青霉素、利福平、链霉素和卡那霉素高度敏感,对氯霉素表现抗性.     

高产大豆新品种东生1号的选育及栽培技术

高产大豆新品种东生1号是中国科学院东北地理与农业生态研究所于1992年以合丰25系选为母本，以北87-19为父本进行有性杂交经过多年选育而成的。该品种适于大豆主产区黑龙江省第三积温带种植，主要特点是株型合理、高产、稳产，抗倒伏、耐旱、耐涝、中抗大豆灰斑病。2003年通过黑龙江省作物品种省定委员会审定，命名为东生1号。     

Production of Avaroferrin and Putrebactin by Heterologous Expression of a Deep-Sea Metagenomic DNA

The siderophore avaroferrin (1), an inhibitor of Vibrio swarming that was recently identified in Shewanella algae B516, was produced by heterologous expression of the biosynthetic gene cluster cloned from a deep-sea sediment metagenomic DNA, together with two analogues, bisucaberin (2) and putrebactin (3). Avaroferrin (1) is a macrocyclic heterodimer of N-hydroxy-N-succinyl cadaverine (4) and N-hydroxy-N-succinyl-putrescine (5), whereas analogues 2 and 3 are homodimers of 4 and 5, respectively. Heterologous expression of two other related genes from culturable marine bacteria resulted in production of compounds 1–3, but in quite different proportions compared with production through expression of the metagenomic DNA.     

The effect of time of harvest on seed production of three red clover cultivars

Small plots of red clover cv. Sabtoron, S123 (diploids) and Hungaropoly (tetraploid) were harvested for seed production at two-week intervals from 19 August to 17 October inclusive in 1981, inflorescence appearance rate, bee density and components of yield having been monitored throughout the summer. Inflorescence appearance rate reached a maximum at the end of July/early August for Hungaropoly and Sabtoron and during mid-August for S123. Bee density followed a similar pattern. Florets and seeds per inflorescence and 1000-seed weight decreased as flowering progressed except during the first three weeks in July. Potential seed yield was calculated from the components of yield for the harvests taken on 3 and 18 September. Losses in seed yield (difference between actual and potential) up to and during harvesting, threshing and cleaning were lower in the tetraploid cultivar (27–39%) than the diploid cultivars (35–l55%). Each cultivar had an optimum harvest time before which yield was affected by immature seeds and beyond which it was adversely affected by shedding of inflorescences and seeds and sprouting of seeds on the inflorescences. The optimum time to harvest Sabtoron was early September, Hungaropoly early to mid-September and the late flowering cultivar S123 mid-September when less than 4% of the inflorescences were still unripe. Seed yield and inflorescences per unit area were lower in the tetraploid cv, Hungaropoly (maximum 542 kg ha⁻¹) than diploid cv. Sabtoron and S123 (864 and 897 kg ha⁻¹ respectively) although the tetraptoid had heavier seeds. It is concluded that the optimum time to harvest red clover for seed production is about three or four weeks after the end of the period of rapid inflorescence production and that this coincides with the time when only a small proportion of unripe inflorescences remain.     

Production of desferrioxamine B (Desferal) using corn steep liquor in Streptomyces pilosus

The aim of this study was evaluation of corn steep liquor as an alternative or substitution medium for production of desferrioxamine B in streptomyces pilosus. Desferrioxamine B is the major siderophore of Streptomyces pilosus. The genus Streptomyces are Gram positive and GC (Guanine/Cytosine) rich bacteria that are important for production of many antibiotics and secondary metabolites. These metabolites get more attention in industrial and medical fields. Desferrioxamine B is used clinically to treat disorders related to iron overload and pathological iron deposition in human. Corn Steep Liquor (CSL) is a by-product of corn wet-milling. It is an excellent source of organic nitrogen and important constituent of some culture media. Nowadays CSL was mainly used for feeding of livestock. In this study we substitute the conventional media with CSL and surveyed its effect on production of desferrioxamine B. The CSL is cheaper than other media and its availability is so easy. In this research, for the first time we used a cheap material for production of a valuable product. Our results showed that the use of CSL solely, increased the production of Desferal more than three times in comparison with conventional media such as soybean.     

Effects of planting date and variety on flooded rice production in the deepwater area of Thailand

Crop management plays an important role in the transition from a deepwater rice to a flooded rice production system but information about optimum management strategies are currently lacking. The goal of this study was to determine the effect of planting date and variety on flooded rice production in the deepwater area of Thailand. Two experiments were conducted at the Bang Taen His Majesty Private Development Project in 2009 and 2010 to represent conditions prior to flooding (early rainy season) and after flooding (dry season). The early rainy season crop covered the period from May to October 2009, while the dry season crop covered the period from November 2009 to April 2010. The experimental design was a split plot with four main plots and three sub plots replicated four times. The treatments for the main plot were various planting dates, while the treatments for the sub plots were rice varieties. The dates of the critical developmental phases of rice were recorded and biomass was sampled during the growing period. The collected data were statistically analyzed using ANOVA and treatment means were compared to identify the appropriate plating date and the best variety for the area. The highest average yield was obtained for variety PSL2 across transplanting dates from June 19 to July 23, with an average yield of 3898 kg ha⁻¹. The dry season crop showed that both biomass and yield were affected by the interaction between planting date and variety. The highest yield was obtained for variety PTT1 transplanted on November 9. The research showed that the variety PSL2 is the most suitable variety for early rainy season production with a transplanting date ranging from June 19 to July 23, while the variety PTT1 planted on November 9 was the best management practice for the dry season crop. However, a high yielding flooded rice variety that has a short growth duration is still needed for this area.     

Production and partial characterization of uric acid degrading enzyme from new source Saccharopolyspora sp. PNR11

The strain PNR11 was isolated from gut of termite during the screening for uric acid degrading actinomyces. This strain was able to produce an intracellular uricase when cultured in fermentation medium containing uric acid as nitrogen source. Base on its morphological characters and 16S rDNA sequence analysis, this strain belong to the genus Saccharopolyspora. This is the first report ofuricase produced from the genus Saccharopolyspora. The aim of this study was to investigate the effects of different factors on uricase production by new source of Saccharopolyspora. Saccharopolyspora sp. PNR11 was cultured in production medium in order to determine the best cultivation period. The result showed that the time period required for maximum enzyme production was 24 h on a rotary shaker operating at 180 rpm. Optimized composition of the production medium consisted of 1% yeast extract, 1% maltose, 0.1% K2HPO4, 0.05% MgSO4 7H2O, 0.05% NaCl and 1% uric acid. The optimum pH and temperature for uricase production in the optimized medium were pH 7.0 and 30 degrees C, respectively. When the strain was cultured at optimized condition, the uricase activity reached to 216 mU mL(-1) in confidential level of 95%. The crude enzyme had an optimum temperature of uricase was 37 degrees C and it was stable up to 30 degrees C at pH 8.5. The optimum pH ofuricase was 8.5 and was stable in range of pH 7.0-10.0 at 4 degrees C. This strain might be considered as a candidate source for uricase production in the further studies. Present finding could be fulfill the information ofuricase produce from actinomycetes.     

Evaluation of actinomycete isolates obtained from herbal vermicompost for the biological control of Fusarium wilt of chickpea

A total of 137 actinomycetes cultures, isolated from 25 different herbal vermicomposts, were characterized for their antagonistic potential against Fusarium oxysporum f. sp. ciceri (FOC) by dual-culture assay. Of the isolates, five most promising FOC antagonistic isolates (CAI-24, CAI-121, CAI-127, KAI-32 and KAI-90) were characterized for the production of siderophore, cellulase, protease, hydrocyanic acid (HCN), indole acetic acid (IAA) and antagonistic potential against Rhizoctonia bataticola, which causes dry root rot in chickpea (three strains viz. RB-6, RB-24 and RB-115) and sorghum (one strain). All of the five FOC antagonistic isolates produced siderophore and HCN, four of them (except KAI-90) produced IAA, KAI-32 and KAI-90 produced cellulase and CAI-24 and CAI-127 produced protease. In the dual-culture assay, three of the isolates, CAI-24, KAI-32 and KAI-90, also inhibited all three strains of R. bataticola in chickpea, while two of them (KAI-32 and KAI-90) inhibited the tested strain in sorghum. When the FOC antagonistic isolates were evaluated further for their antagonistic potential in the greenhouse and wilt-sick field conditions on chickpea, 45-76% and 4-19% reduction of disease incidence were observed, respectively compared to the control. The sequences of 16S rDNA gene of the isolates CAI-24, CAI-121, CAI-127, KAI-32 and KAI-90 were matched with Streptomyces tsusimaensis, Streptomyces caviscabies, Streptomyces setonii, Streptomyces africanus and an identified species of Streptomyces, respectively using the BLAST searching. This study indicated that the selected actinomycete isolates have the potential for biological control of Fusarium wilt disease in chickpea.