Molecular cloning and sequence analysis of an LFY homologous gene from Juglans regia L.

The existence of a long juvenile phase is found seriously to affect the early-stage economic benefits of later mature walnuts (Juglans regia L.). Studies on LFY, a key gene controlling floral transition and flower differentiation, may be helpful in solving the problem. This study reports the identification and characterization of a JrLFY gene from Juglans regia L., a homolog of FLORICAULA/LFY. The gene was isolated from flower buds of precocious walnut cultivar Zhonglin No. 5 by RT-PCR and RACE. The cDNA sequence of JrLFY (GenBank accession no. GU194836) was 1496 bp and contained an ORF of 1158 bp. Its corresponding genomic sequence (GenBank accession no. HQ019159) showed that the JrLFY contained three exons and two introns. The predicted amino acid sequence of the gene consisted of 385 amino acids and had a conserved region in the C-terminal when being aligned with sequences of other LFY homologs. Phylogenetic analysis showed that the LFY protein of walnut was close to those of hickory and chestnut. These studies will lay a foundation for understanding the mechanism of early fruiting and preparation for transfer of the JrLFY as a transgene to later mature walnuts.     

不同供磷水平对胡麻磷素养分转运分配及其磷肥效率的影响简

 以“坝选３号”胡麻为材料，研究了不施磷、低磷、中磷和高磷４ 个不同施磷（Ｐ_２Ｏ_５）水平（０，３５，７０ 和１０５ｋｇ／ｈｍ^２）对胡麻植株中磷素累积、转运、分配和磷肥利用效率的影响。结果表明，低磷、中磷和高磷水平时，胡麻各器官不同生育阶段磷素养分吸收和累积量的基本趋势一致，但其变化量与施磷量有极大关系。胡麻地上茎、叶、非籽粒和籽粒中，磷素的日增量增幅因器官而异；胡麻只有叶片中有磷素转移，中磷处理比低磷和高磷处理磷转移量增加５４．９３％～７３．８３％和８．１９％～１０．００％（P＜０．０５），籽粒中２０．４６％～３５．９３％ 的磷素是靠叶片转运而来。胡麻植株磷素累积主要在生殖生长阶段，占整个生育期总累积量的７９．０２％～９２．１７％。施磷（Ｐ_２Ｏ_５）量为７０ｋｇ／ｈｍ^２时磷肥表观利用率和农学效率最高，分别为２０．２２％～２０．５３％和７．３０～７．４４ｋｇ／ｋｇ。胡麻产量随施磷量增加而增加，增幅最高达２８．９６％～３１．４６％。结合产量与磷肥表观利用率和农学效率，本实验区同等肥力土壤条件下，以施磷（Ｐ_２Ｏ_５）量为７０ｋｇ／ｈｍ^２（中磷）为宜。     

探讨园林绿化的市场运作

将园林绿化的工作通过市场的运作,逐步实现市场管理,从无形到有形,从无序到有序的转变。     

试述北京市农机报废更新工作的迫切性

为保证北京市农机安全生产工作,大力促进农业生产的发展,北京市建立农机报废更新制度迫在眉睫。     

基于云计算的农业信息整合安全模型研究

利用云技术整合农业数字资源是未来发展趋势,本研究中为确保农业信息的云安全,提出了一种网络安全模型,并通过仿真验证网络安全模型的合理性。     

“中国春”小麦不同缺体的RAPD分析

利用ＰＣＲ－９０Ａ型ＤＮＡ扩增仪，对７个中国春小麦缺体核ＤＮＡ进行了扩增。结果显示，中国春小麦缺体核ＤＮＡ的ＲＡＰＤ产物可分为二种类型：（１）所有供试材料均能扩增出的片段，代表了核ＤＮＡ在进化上的保守性。有一个引物检测到这类片段。（２）全部供试材料间存在的差异片段，这类片段是用来基因定位的主要依据。另外，建立中国春小麦缺体系统的ＲＡＰＤ指纹图谱对研究小麦的系统进化也将有重要意义     

“906”免疫增强剂对鸡新城疫H_I抗体效价的影响

实验观察了“９０６”免疫增强剂对鸡新城疫ＨＩ抗体效价的影响。结果表明，“９０６”免疫增强剂可显著提高鸡新城疫Ｉ系苗的免疫效果（Ｐ＜０．０５），而且在３０天内与油乳剂疫苗免疫具有相近的抗体水平（Ｐ＞０．０５）。     

Inhibition of porcine circovirus type 1 and type 2 production in PK-15 cells by small interfering RNAs targeting the Rep gene

Porcine circovirus type 1 (PCV1) and type 2 (PCV2) are two genotypes of porcine circovirus. Both of them are presumed to be widespread in the swine population. Currently, there is no specific treatment for their infections. RNA interference (RNAi) is a sequence-specific RNA degradation mechanism mediated by small interfering RNA (siRNA), which represents a possible therapeutic application for the treatment of viral infections. In this study, three siRNA expression plasmids (pS-RepA, pS-RepB and pS-RepC) were generated to target three different coding regions of the Rep protein (Rep) of PCV. These siRNAs were used to inhibit PCV production in a porcine kidney cell line, PK-15 cells. Our results revealed that Rep gene expression was inhibited by pS-RepA, pS-RepB and pS-RepC to different degrees. Moreover, our study also showed that the production of PCV1 and PCV2 was reduced by these siRNAs. pS-RepC, which targets the middle region of Rep gene, proved to be the most efficient siRNA for inhibition of Rep expression and viral production. Taken together, our data suggest that RNAi could be investigated as a potential treatment for PCV infection.     

非亲和性稻瘟病菌对水稻的诱导抗性

为研究稻瘟病菌Magnaporthe oryzae不同菌株间的相互作用,选择与单抗性基因系水稻IRBL5-M （携带抗性基因Pi5）表现为亲和性的菌株HN52与非亲和性的菌株HN119为研究对象,将其单独或混合接种到单抗性基因系水稻IRBL5-M中,并通过荧光显微镜观察接种后水稻叶鞘的发病情况及病斑面积,测定接种后水稻内相关抗性基因OsWRKY45、OsNPR1、OsPR10、OsMAPK2的表达量以及活性氧的变化。结果显示,相较于单独接种亲和性菌株,混合接种后单抗性基因系水稻IRBL5-M病斑发病面积减少;混合接种中亲和性菌株HN52菌丝侵染能力降低,侵染菌丝细胞间扩展率显著降低73.13%;同时单抗性基因系水稻IRBL5-M中OsWRKY45、OsNPR1、OsPR10和OsMAPK2抗性基因表达量显著增加,水稻叶片中活性氧含量增加,表明在菌株混合侵染过程中,非亲和性菌株可通过激发水稻的抗性反应来降低亲和性菌株对水稻的侵染程度。