黑龙江大兴安岭兴安落叶松林土壤热通量研究

利用气象梯度观测塔安装的土壤热通量板和净辐射传感器等设备对大兴安岭的兴安落叶松林土壤热通量的特征及与净辐射相关性进行了分析。结果表明：5cm土壤热通量的日变化和年变化均呈现出＂S＂形,土壤热通量在年度6月达到最大值747.35W·m-2,12月达到最小值-394.55 W·m-2,全年总土壤热通量为738.89 W·m-2,全年土壤总的热通量为正值,土壤为热汇。对5cm土壤热通量和冠层净辐射相关性进行了回归分析,无论在日尺度还是在年尺度上均达到显著相关性。     

Salix tetradenia Hand.‐Mazz: a new natural plant host of ‘Candidatus phytoplasma’

This article reports Salix tetradenia Hand.‐Mazz as a new host of Candidatus phytoplasma and demonstrates its association with witches' broom disease on S. tetradenia plants. Plants exhibited typical visual symptoms of phytoplasma with virescence, abnormality of flowers and witches' broom, and phytoplasma bodies were observed by transmission electron microscopy. Products of 1.2 kb were amplified by nested PCR using phytoplasma universal primer pairs R16F2n/R16R2, but no amplification products were obtained from symptomless plants. The sequence analysis of three 16S rDNA isolates showed 99.84%, 99.68% and 99.76% identify, respectively, with the homologous gene (nc_005303) of member of ‘Candidatus phytoplasma asteris’ (16SrI) group. Phylogenetic and virtual computer‐simulated restriction fragment length polymorphism analysis of the 16S rRNA, tuf and rp gene sequences confirmed that this phytoplasma clustered in the 16SrI‐B subgroup. These results indicated that the diseased S. tetradenia plants were infected by a phytoplasma of the 16SrI group. This is the first report on the occurrence of phytoplasma disease on S. tetradenia worldwide.     

生物降解农药残留的研究进展

为了促进农药的降解,减少农作物中的农药残留量,本研究归纳了农药降解的方法,主要包括光解、化学降解和生物降解,分析了各种农药降解方法的优点和缺点,总结了外源物质(农药安全剂、油菜素内酯、褪黑素)促进农作物体内农药降解的途径及机理.指出了寡糖降低作物中农药残留的作用以及可能的机理,提出了关于促进农作物体内农药降解研究方面存...     

核桃专用生物-有机-无机复混肥对核桃种植的影响

目前核桃专用肥以复混肥搭配有机肥为主,肥料利用率较低,且会造成肥料浪费,增加施肥成本;本研究结合核桃需肥规律和核桃主产区土壤养分情况,针对核桃专用肥的施用现状在云南核桃主产区进行生物-有机-无机复混肥的应用研究,旨在提高肥料利用率、减少肥料施用量和提高核桃产区土壤微生物活性;在肥料施用期间检测土壤微生物情况以及功能菌株...     

利用Pi-1基因邻近SSR标记鉴定稻瘟病抗性

Pi-1是具有广谱抗性的水稻显性主效抗稻瘟病基因,位于水稻11号染色体末端。本研究选择靠近此处的SSR标记15对,用含有Pi-1基因的Lac23与不含Pi-1基因恢复力强的N优69-1进行检测。检测出有差异条带5对引物,分别为RM224、RM254、RM2136、RM6094和RM6293。另外,以N优69-1为母本,以LAC23为父本进行杂交至F8代群体,利用上述差异分子标记,在F8趋亲单株中选择与Lac23标记一致的单株,与田间稻瘟病鉴定结果相比较。结果显示,RM6293对含有Pi-1基因材料的选育有较大的准确度,其次为RM254RM224RM2136RM6094。本实验与其它研究不同的是采用了F8代群体,认为多次自交重组后的遗传稳定株系才可能得到稳定的标记。     

对我国玉米科研生产中若干问题的思考

我国是玉米生产和消费大国,育种单位众多,但所育品种同质化程度高,个性化品种少,品种寿命短.应组建生态区玉米育种中心,协作开发,提高玉米育种水平.对玉米品种审定、区试、扩展DNA指纹鉴定用途等提出建议.     

绒毛白蜡NADH还原酶第二亚基(NDHB)基因片段的克隆及同源性分析

克隆并分析绒毛白蜡NADH还原酶第二亚基(NDHB)基因片段.根据GenBank上已发表的NDHB氨基酸序列,设计合成了一对简并引物,采用RT-PCR技术对绒毛白蜡NADH还原酶第二亚基基因进行扩增,将扩增的PCR产物与pMD18-T连接后转化至E.coli JM109感受态细胞,检测阳性克隆,测序并进行序列分析.克隆的绒毛白蜡NADH还原酶第二亚基基因cDNA序列长893bp,由288个氨基酸残基组成,命名为FvndhB.序列比对结果表明FvndhB与参考的8个物种的NDHB在核酸水平上表现出较高的同源性,其与桑树、银白杨、按树、烟草、拟南芥、银杏、台东苏铁、日本柳杉NDHB核苷酸序列同源性分别为84.32%、83.88%、83.43%、82.86%、82.18%、78.82%、77.07%、71.23%.利用DNAMAN软件构建的系统进化树显示绒毛白蜡与其他植物亲缘关系较远.成功获得了绒毛白蜡FvndhB基因片段,并对其进行了同源性分析,为进一步克隆绒毛白蜡FvndhB全长基因及分析其表达特性奠定了基础.     

温热环境对肉仔鸡胸囊肿发生的影响

为探讨不同温热环境对肉仔鸡胸囊肿发生的影响,该试验研究了生产实际中夏季和秋季的鸡舍环境温湿指数（THI）、温度和相对湿度（RH）的变化以及对肉仔鸡胸囊肿发生率的影响。结果表明,夏季鸡舍环境中平均THI、温度和RH均高于秋季,尤其在肉仔鸡6周龄时夏季比秋季THI、最高平均温度和RH分别高4.3、7.3℃和13%。而肉仔鸡胸囊肿发生率夏季低于秋季,5、6周龄分别下降21.56%和40.22%。夏季和秋季不同的温热环境中,肉仔鸡血液的抗氧化能力发生了显著的变化,血清总抗氧化力（T-AOC）夏季显著大于秋季,丙二醛（MDA）含量则相反,秋季显著大于夏季。因此,本研究表明了高温环境可使肉仔鸡胸囊肿发生率降低,并且,可能与抗氧化能力的提高有关。     

Genetic diversity of Cucurbita maxima assessed using morphological characteristics and random-amplified polymorphic DNA markers in China

Cucurbita maxima is one of the most widely cultivated Cucurbitaceae in Heilongjiang province, China. The objectives of this study were to clarify the genetic diversity of 44 accessions from different geographical origins using morphological and molecular characteristics and to compare the consistency of these morphological and molecular characteristics. Morphological characteristics showed a large qualitative variability primarily according to fruit-related traits. Twenty-eight random-amplified polymorphic DNA (RAPD) markers produced 128 bands. Both morphological characteristics and RAPD markers grouped 44 accessions of C. maxima into four clusters, and the similarity coefficients ranged from 0.70 to 0.91 and from 0.40 to 0.98, respectively. DNA polymorphisms were highly consistent with phenotypic traits on rootstock C. maxima. The relationships between C. maxima from different origins were not clearly defined via morphological characteristics and RAPD analysis, suggesting some traits of C. maxima were specific to geographical location had disappeared or were weak in Heilongjiang province, which would not facilitate pumpkin breeding. Hybrid generations and their parent plants or sister lines were grouped into sub-clusters and showed little genetic distance according to both evaluation methods. Overall, morphological characteristics and RAPD markers were consistent and revealed high genetic diversity between C. maxima landraces from different origins.