Effects of basic density,annual growth and drying schedule on selected quality factors of dried Siberian larch (Larix sibirica) timber

Abstract

Siberian larch (Larix sibirica Ledeb.) timber is suitable for many uses in the mechanical wood industry. Drying it without any decrease in value, however, is difficult and slow. The purpose of this research was to compare the drying quality of Siberian larch timber dried with three different conventional schedules taking into account the density and annual growth of wood. Five drying tests were performed. The final moisture content (MC), MC gradient, cracks, deformations (bow, crook, twist and cup) and case hardening were measured from the dried timber. The basic density particularly affected the MC, as shown in the differences regarding dried wood, with the denser wood having higher final MC and MC gradient. It was also found that large annual growth increased some deformations. Most of the measured factors were best after drying at the highest temperatures used; however, a slightly different trend was observed for bow, twist and cup. MC factors and twisting were the most problematic properties in drying according to this study. Sorting Siberian larch timber, particularly according to density, would improve the MC properties of dried timber by ensuring sufficient drying time, as economically as possible, for each timber piece.     

肥料种类对花生生长发育的影响

采用配方施肥与常规施肥方法结合大区试验对花生植株生长状况、产量、经济效益及土壤养分含量进行研究。结果表明,多营养元素配方施肥对促进植株生长效果明显,能明显提高花生产量,增加花生经济效益。目前条件下,以每hm2施肥量N127．2kg、P2O5 60．2kg、K2O90．0kg为宜。     

Proteomic Identification of Differentially Expressed Proteins in Vaccaria segetalis-treated Dairy Cow Mammary Epithelial Cells

To investigate the potential effects of Vaccaria segetalis, we employed the proteomic approach on the dairy cow mammary gland epithelial cells (DCMECs). A total of 35 differentially expressed nuclear proteins were visualized by 2-DE and silver nitrate staining. Of these, five proteins also displayed significant expression changes upon treatment of the water decoction from Vaccaria segetalis, and such alterations were further confirmed by RT-PCR. Together, at both the mRNA and protein levels, the water decoction from Vaccaria segetalis increased the expression of proteins ethylmalonic encephalopathy 1 (ETHE1), vesicle amine transport protein 1 homolog (VAT1), parkinson disease protein 7 homolog (Protein DJ-1), proteasome subunit alpha type-2 (PSMA2) and SUMO-activating enzyme subunit 1 (SAE1). This study would enable a better understanding of the molecular mechanisms underlying this water decoction effects at the protein level.     

猪繁殖与呼吸综合征和猪乙型脑炎双重一步法RT-PCR诊断试剂盒的研制

根据GenBank中的猪繁殖与呼吸综合征病毒（PRRSV）ORF7N基因、猪乙型脑炎病毒（JEV）NS1基因序列,设计了2对引物,通过反应条件的优化,成功研制了检测PRRSV和JEV的双重一步法RT-PCR诊断试剂盒,扩增产物分别为245、504 bp。敏感性、 特异性结果显示,该RT-PCR诊断试剂盒对2种病毒的最低核酸检测量分别为PRRSV0.2ng/L、JEV 0.4ng/L,而对猪瘟病毒、猪伪狂犬病毒、猪圆环病毒2型、猪细小病毒的扩增结果均为阴性。对52份疑似病猪样品的检测结果表明,该双重一步法RT-PCR诊断试剂盒检测结果与单一PCR检测结果完全符合。结果表明该双重一步法RT-PCR诊断试剂盒具有很好的特异性和敏感性,可用于临床猪繁殖与呼吸综合征和猪乙型脑炎的检测。     

干旱胁迫下15种丹参miRNAs差异表达分析

参考已报道的其他植物中响应干旱胁迫的miRNAs,以其中15个miRNAs为研究对象,10％ PEG6000胁迫处理的丹参幼苗为材料,采用实时定量PCR技术分析了这些miRNAs在于旱胁迫前后丹参幼苗叶片中的差异性表达.结果表明,在干旱胁迫6h后,丹参体内miR156、miR157、miR166、miR168、miR169、miR319、miR774、miR894、miR2911、miR3462以及miR3626的表达水平表现为不同程度的上调,其中miR157、miR166、miR319、miR774、miR894、miR2911和miR3626表现为显著性上调;miR159、miR167、miR172以及miR408则表现为下调.对这些miRNAs作用的靶基因进行预测和分析发现,它们主要参与植物的新陈代谢、信号传导和生长发育过程,推测miR169和miR3462参与了丹参对干旱胁迫应答过程.     

Soil Ecosystem Changes During the Transition to No-Till Cropping

Summary

Growers in the United States and worldwide are adopting no-tillage (no-till) cropping to reduce soil erosion, improve soil quality, increase water infiltration, and reduce number of passes with farm equipment over their fields. Soil erosion from dry farmed (i.e., non-irrigated) cropland in most regions of the United States exceeds the tolerable rate. An understanding of the changes in the soil ecosystem with changing tillage practices is needed to minimize the impact of agriculture on the environment and foster the use of sustainable agricultural practices. The soil biota is critical to the functioning of any agro-ecosystem, but studying the soil biota is difficult due to the diversity and the challenges associated with isolating and identifying these organisms. Soil disturbance or lack of disturbance can have a profound effect on biotic populations, processes and community structure. This contribution examines changes that occur in soil during the transition to no-till cropping, interrelations among organisms in the soil food web, and the relationships between organisms and their environment. As interest grows in sustainable cropping systems that mimic processes and soil organic matter turnover of native, undisturbed systems, it is imperative to understand how the transition to no-till affects an organism's niche, or functional role within the soil environment. Ecosystem investigations will enhance the understanding of changes that occur with the adoption of reduced tillage and no-till cropping systems so that these systems become increasingly viable.     

蕙兰Flowering locus T基因的克隆及其对开花的影响

【目的】 探讨CfFT基因在蕙兰成花中的作用。【方法】采用RT-PCR结合RACE技术从蕙兰(Cymbidium faberi)中克隆Flowering locus T（FT）同源基因CfFT。采用实时定量RT-PCR对不同组织及不同花发育时期CfFT进行表达分析。将该基因克隆到PBI121载体上导入烟草中,并对不同转基因烟草株系中的CfFT、NFL、NtFUL和NAP1基因进行实时定量RT-PCR分析。【结果】对蕙兰花芽分化不同时期的CfFT的表达分析表明,CfFT在花芽分化初期的表达量最高,之后随着花芽的成熟表达量逐渐降低。将CfFT导入烟草进行异源表达,转基因株系表现出明显的早花表型。对开花时间不一的转基因株系中的CfFT表达分析表明,其表达量与转基因烟草开花时间早晚成正比。进一步对这些株系内源的NFL、NAP1和NtFUL表达分析表明,NFL、NAP1和NtFUL基因的表达量与CfFT表达成正比,说明NFL、NAP1和NtFUL的表达受FT基因的上游调控。【结论】在烟草中异源表达蕙兰中的CfFT基因能促进烟草提前开花。     

禽流感H9亚型一步法RT-PCR快速检测试剂盒的研制及应用

为建立一种简单、快速、灵敏、准确的禽流感H9检测方法,本研究根据GenBank中收录的禽流感H9病毒高度保守的基因序列,设计1对H9的特异性引物,建立了一步法快速检测禽流感的PCR,对反应条件进行优化后,组装成快速检测试剂盒,并对临床收集的疑似禽流感病料进行检测。结果显示,试验成功建立了禽流感H9病毒一步法RT-PCR检测方法,在此基础上完成了试剂盒的组装,对30份疑似禽流感病料的检出率高达98%以上,检测灵敏度达10^1.5ELD₅₀,稳定性良好, 冷冻保存期达12个月。经证实该试剂盒具有操作简便、经济、快速、灵敏度高、特异性强、重复性好、稳定性高等优点,值得推广应用。     

猪流行性腹泻病毒RT-PCR检测与ORF3基因分子流行病学调查

为调查乳仔猪腹泻引起疫情的病原,本研究自2011年2月至2012年3月收集华东地区47个规模猪场共153份腹泻病料样品,采用RT-PCR检测猪流行性腹泻病毒(PEDV),并进行ORF3基因序列分析.结果显示:26个猪场的88份样品为PEDV阳性,猪场阳性率达到55.32％,病料阳性率达到57.52％.ORF3基因测序分析显示:11个流行病毒株ORF3全基因序列大小均为675bp,编码224个氨基酸.11个流行株ORF3基因同源性为95.9％～99.9％,编码氨基酸同源性为96.4％～100％.与欧洲代表性强毒株CV777基因同源性为96.3％～97.0％,编码氨基酸同源性为95.1％～96.4％,与CV777弱毒疫苗株基因同源性为96.8％～97.6％,编码氨基酸同源性为92.3 ％～93.4％,并且无疫苗病毒株ORF3基因的49个碱基缺失.与韩国病毒株比较,其基因同源性为95.0 ％～98.5％,编码氨基酸同源性为95.5％～99.6％.基因遗传进化树分析表明,国内外PEDV株可分为4群.我国主要流行病毒株属于第1群,与韩国病毒袜亲缘关系较近,而与我国疫苗病毒株存在较大差异.该研究表明,PEDV可能是目前我国仔猪腹泻的主要病原之一,我国PEDV流行病毒株存在明显基因变异.     

安徽省水稻黑条矮缩病毒和南方水稻黑条矮缩病毒的 分子检测和序列分析

近年来,水稻黑条矮缩病毒(RBSDV)和南方水稻黑条矮缩病毒(SRBSDV)在安徽各稻区危害日益严重,生产上仅凭症状难以区分2种病毒。本研究建立的RT-PCR方法可以实现一次性检测和鉴定RBSDV和SRBSDV 2种病毒,根据RBSDV和SRBSDV S9保守序列设计3个引物,不仅可以从单独感染RBSDV或SRBSDV的水稻样本中分别扩增出1条大小不同的特异性条带,而且还可以从感染RBSDV和SRBSDV的混合水稻样本中一次性扩增出2条大小不同的特异性条带。从安徽省庐江县、郎溪县、怀宁县和宣州市4个地区水稻田采集表现明显矮缩病症状的水稻样本,RT-PCR检测结果表明,庐江和郎溪水稻样本受到RBSDV侵染,怀宁和宣州水稻样本受到SRBSDV侵染。选取庐江县、郎溪县、怀宁县和宣州市各1个水稻样本,利用RT-PCR扩增出特异性条带,再分别克隆和测序。序列分析表明,庐江、郎溪2个样本的核苷酸序列与RBSDV-Shandong和RBSDV-Zhjr S9部分片段序列相似性高达99.3%～99.8%,且与RBSDV的亲缘关系最近,说明庐江和郎溪样本感染的病毒是RBSDV的2个分离物;怀宁、宣州2个样本的核苷酸序列与SRBSDV-Shangdong和RBSDV-2 S9部分片段序列相似性高达99.5%,且与SRBSDV亲缘关系最近,说明怀宁和宣州样本感染的病毒是SRBSDV的2个分离物。