长期施肥下我国水稻土基础地力变化趋势

【目的】水田具有较好的水热稳定性,且基础地力对水稻产量的贡献大,所以水稻土基础地力高低是保证水稻高产稳产的重要指标。研究长期不同施肥下我国不同区域水稻土基础地力的变化态势及其特征不仅为水稻土的农业可持续生产提供理论依据,还为评价和建立长期合理的施肥模式提供数据支持。【方法】以不施肥处理(CK)的水稻产量表征其基础地力,以不施肥产量与常规施肥(施氮、磷、钾肥,NPK)产量的比值作为基础地力贡献率,分析了我国7个水稻连作或稻麦轮作农田生态系统下长期施肥稻田的基础地力和基础地力贡献率随时间的变化趋势和特征,比较了不同地点及不同轮作方式的差异探讨了基础地力贡献率与水稻产量及其相关指标的关系。【结果】长期不施肥水稻产量随时间的变化总体上较稳定,平均变化速率仅为-0.3 kg/(hm~2·a)。不同水稻土类型间差异大红壤水稻土基础地力易呈下降趋势而紫色水稻土较稳定。不同轮作方式上,晚稻和单季稻的不施肥产量随时间呈上升趋势,分别增加1.6和29.2 kg/(hm~2·a),而早稻不施肥产量呈逐年下降趋势,平均下降20.0kg/(hm~2·a)。同一区域的试验点,白沙(BS)和望城(WangC)不施肥的水稻产量逐年下降速率最大,下降值达47~82kg/(hm~2·a);而南昌(NC)的早晚稻、武昌(WuC)和遂宁(SN)的单季稻均呈逐年上升的趋势,上升速率达44~81 kg/(hm~2·a)。水稻多年(20年)平均基础地力贡献率较高(各地变化幅度42%~68%,平均值为59.7%)其中早稻、晚稻和单季稻分别为55.1%、67.1%和54.9%。基础地力贡献率与不施肥的产量可持续性指数(SYI)间呈显著的正相关关系(r=0.655,n=13)。7个试验点的多年施肥处理水稻平均产量为5100 kg/hm~2,显著高于不施肥产量(2911 kg/hm~2),多年施肥措施对水稻产量的贡献率为40.3%。【结论】长期不施肥晚稻和单季稻产量稳定或有上升趋势而早稻产量不稳定,部分呈显著下降趋势,其变幅大小与水稻土类型有关,其中红壤水稻土的早稻产量易呈下降趋势而紫色水稻土的最稳定;施肥条件下各试验点水稻产量随时间变化较稳定。从长期角度而言,提高南方水稻土基础地力是提升其产量可持续性的有效途径之一。     

河流型水牛种公牛染色体罗伯逊易位筛查

为了筛查河流型水牛种公牛染色体罗伯逊易位,试验采用常规微量全血培养和空气干燥制片法对摩拉水牛、尼里/拉菲水牛、地中海水牛及其杂交后代共49头河流型水牛种公牛进行染色体的遗传检测和分析。结果表明:河流型水牛种公牛染色体数目均为2n=48+XY,包含5对双臂(中部、亚中部或亚端部)常染色体、19对端部着丝粒常染色体和1对性染色体,未发现染色体罗伯逊易位现象。     

Cloning and Bioinformatics Analysis of FADS2 Gene in Buffalo

This study was aimed to clone the buffalo Δ6-fatty acid desaturases (FADS2) gene using in-Silico cloning and analyze its genetic struction with bioinformatics, which provide a foundation for investigating the milk performance in buffaloes. Primers were designed according the sequence of FADS2 gene in dairy cow (GenBank accession No.:NM_001083444.1). The FADS2 gene was amplified by RT-PCR, and its sequence was analyzed by bioinformatics. Sequence analysis revealed that the buffalo FADS2 gene had 36 600 bp in length and consisted of 12 exons and 11 introns, containing an open reading frame (ORF) of 1 335 bp which encoding 444 amino acids. Sequence homology analysis indicated that the buffalo FADS2 protein gene showed 98.88%, 98.88%, 89.66%, 90.79%, 90.85%, 92.35% and 87.11% identity with that of Bos mutus, Bos taurus, Homo sapiens, Sus scrofa, Oryctolagus cuniculus, Orcinus orca and Rattus norvegicus, respectively. Protein prediction analysis showed that the molecular weight and isoelectric point (pI) of buffalo FADS2 were 52.51 ku and 8.75, respectively, and the FADS2 protein was weak alkali and the hydrophobicity protein without signal peptide. Phylogenetic tree analysis showed that FADS2 gene was highly conserved in different species and evolutionary processes,buffalo was close to Bos mutus and Bos taurus, and was far from Rattus norvegicus. This study suggested that FADS2 gene was successfully cloned in buffalo, which laid a foundation for clarifying the mechanism of milk performance in buffalo.     

Cloning and Construction of Eukaryotic Expression Vector of Buffalo HSD17B1 Gene

In order to clarify the effect of 17 beta-hydroxysteroid dehydrogenase 1 (HSD17B1) gene on the reproductive performance of buffalo,in this study,buffalo HSD17B1 gene was cloned by 3'-RACE,analyzed by bioinformatics,and studied with eukaryotic vector construction and cell transfection technology.The results showed that the coding region of buffalo HSD17B1 was 954 bp,3'-UTR was 58 bp,encoded 317 amino acids.The buffalo HSD17B1 gene shared 100%,100%,92%,94%,87%,87% and 87% of similar nucleotide sequence with that of Bos taurus,Ovis aries,Sus scrofa,Equusca ballus,Canis lupus,Loxodonta africana and Homo sapiens,respectively.Phylogenetic tree analysis showed that HSD17B1 gene was highly conserved in different species and evolution.HSD17B1 protein was weakly acidic,without signal peptide,located inthe cytoplasmic,and with the presence of type1_17beta-HSD-like_SDR_c,PRK05993,LPOR and FabG domains.The buffalo HSD17B1 eukaryotic expression vector was successfully constructed,after transfected into 293T cell lines,HSD17B1-EGFP fusion protein was detectable.In a word,the success cloning and construction of eukaryotic expression vector of buffalo HSD17B1 gene,provided an important reference for surveying the regulation mechanism of HSD17B1 gene during buffalo folliculogenesis and embryogenesis.     

Effects of sera containing Kang xian ling on c-Met and its downstream MAPK signal molecules in HK-2 cells treated with TGF-β1

AIM: To observe the effects of sera containing Kang xian ling (a traditional Chinese medicine) on c-Met and its downstream MAPK signal molecules in HK-2 cells treated with transforming growth factor-β1(TGF-β1), so as to further explore the effective mechanism of anti-renal fibrosis of the traditional Chinese medicine. METHODS: Rat sera containing herbs were collected after rats were intragastrically administered with the herbs. HK-2 cells activated by TGF-β1 were incubated with different heat-inactivated sera. The proliferation and expression of MAPK and the phosphorylation of MAPK in HK-2 cells were detected by Alarm blue and immunoblotting. RESULTS: No significant difference of cell proliferation between any two groups was observed. c-Met and the phosphorylation of its downstream molecules were also observed after incubated with different sera. CONCLUSION: The receptor c-Met of hepatocyte growth factor, and the phosphorylation of its downstream MAPK molecules can be regulated by the sera containing Kang xian ling.     

中小规模猪场现状与改进

中小规模化的猪场是我国目前养猪业的主要存在方式,论文简要分析了我国中小猪场的现状以及改进处理措施,以实现我国养猪业的健康可持续发展。     

低成本酚醛树脂压制家具用胶合板的研究

酚醛树脂是一类性能优良的结构胶黏剂,但价格昂贵。在保证胶合强度的条件下,试验引入价廉的尿素替代部分苯酚,以降低酚醛树脂生产成本。试验表明,对酚醛树脂性能影响的主次依次为:尿素含量聚乙烯醇用量NaOH用量。通过正交试验确定出尿素改性酚胶试验的最佳工艺条件:甲醛(37%)的加入量为272s,苯酚的质量为120s,尿素含量为30%,摩尔比1:0.65(P/NaOH),聚乙烯醇的加人量为6g,所制得的改性酚醛树脂的胶合强度优异,且成本降低。     

花山喀斯特风景林群落结构与林内景观质量的关系

全面和正确地认识群落结构特征与景观美学质量的关系,对揭示森林景观美学质量的形成机制和进行景观质量提升具有重要意义。采用美景度评价法(Scenic Beauty Estimation,SBE)和回归分析,从林分水平结构、垂直结构和物种组成等群落结构特征层面,分析群落结构特征与景观质量的关系。结果表明:群落结构要素对美景度贡献大小顺序依次为Pielou均匀度指数乔木层密度Shannon-Wiener多样性指数林层数乔木层平均高度;Pielou均匀度指数和乔木层密度与美景度呈负相关关系,Shannon-Wiener多样性指数、林层数和乔木层平均高度与美景度呈正相关关系;物种丰富、乔木层密度较小、林层数多、乔木层平均高度较大的林分具有较高的美景度值。根据群落结构和林内景观质量关系得出群落结构优化策略,首先尽可能满足物种多样性和生态系统稳定性的需求,在此前提下从水平和垂直结构等空间配置上,综合运用林分抚育、林下层管理和美学规划等措施,构建出符合生态要求和具有较高美学价值的森林景观。     

化学镀铜杨木单板的导电性与电磁屏蔽效能分析

为了给电热式化学镀铜地热地板研究提供参考,对化学镀铜杨木单板的导电性与电磁屏蔽效能进行测试,分 析镀层厚度与吸收损耗、反射损耗、趋肤效应的关系。结果表明:镀铜杨木单板屏蔽效能主要以反射损耗为主,属 于反射型电磁屏蔽材料;表面电阻率随镀层厚度的增加呈减小趋势,横纹方向的表面电阻率是顺纹方向的3 倍左 右;频率越高,电磁波在镀铜层中传导时的趋肤深度越小,通过计算趋肤深度确定化学镀铜层的厚度,可以节省镀 铜时间并节约成本。      

林产化工专业构建“一三一”课程实践教学体系的思考

林产化工专业是以林业资源和产品为研究对象的应用型工科专业,与其它工科专业相比有较大的特殊性。为弥补林业院校胶体和表面化学课程的实践教学中还存在的不足,从学校实践教学的实际出发,以胶体与表面化学课程为核心,融合各独立的教学实践环节,革新教学模式,构建"一三一"课程实践教学体系,包括1门课程、3个基本实践教学环节和1个重点教学环节。以课程实验为基础环节,其它3环节为深入教学环节,贯穿胶体与表面化学课程基本知识和概念,同时创新各环节教学内容、组织形式和考核方式,构建"一三一"课程实践教学体系。