杉木无性系木材干缩性与吸水性的变异

以102个17年生杉木无性系为试材,对木材的干缩性与吸水性进行测定分析发现,木材干缩性、吸水性在杉木无性系间差异极显著;干缩性变异幅度为3.1%～20.0%,表型变异系数达59.8%;吸水性变异幅度在214.5%～338.1%间,表型变异系数为13.2%。木材干缩性与吸水性均具有明显的无性系方差分量,表明杉木木材干缩性与吸水性受遗传控制。进一步研究显示,杉木无性系木材干缩性遗传变异系数为38.6%,重复力为0.390,均属中低水平;吸水性遗传变异系数值虽较低,但重复力相对较高(0.664),属中上水平;在不同入选率(10%、20%、30%)下,木材干缩性与吸水性随入选率的降低其遗传增益值(绝对值)不断提高。研究还发现,杉木木材干缩性与木材基本密度、心材比间为极显著遗传负相关,与木材吸水性间则表现为极显著遗传正相关;木材吸水性在遗传水平上与胸径、材积、心材比间呈极显著正相关,而与木材基本密度间为极显著负相关。     

亚洲小车蝗飞行能力及其与种群密度的关系

在室内对我国北方草原优势种蝗虫--亚洲小车蝗（Oedaleus asiaticus）成虫连续悬吊飞行测试12 h,分析成虫飞行能力及其与种群密度的关系。结果表明,亚洲小车蝗高密度种群的飞行能力较强,最远的累计飞行距离可达15 km,累计飞行时间超过2 h。不同日龄的成虫飞行能力有显著差异,羽化后4日龄成虫的飞行能力较弱,以13日龄成虫的飞行能力最强,20日龄显示出下降趋势。雌雄个体间飞行能力无显著差异（P>0.05）。低密度种群成虫不具备远距离飞行的能力,各日龄成虫累计飞行距离和飞行时间均极显著短于同日龄的高密度区个体（P<0.01）。     

犬瘟热病毒和犬腺病毒2型双重PCR方法的建立及应用

根据犬瘟热病毒(canine distemper virus,CDV)和犬腺病毒2型(Canineadenovirus type2,CAV-2)GeneBank登陆的基因序列各设计一对引物,经试验条件优化,建立了检测CAV-2的PCR方法和CDV的RT-PCR方法,CAV-2可扩增1108bp片段、CDV可扩增560bp的目的片段,特异性试验表明建立的方法只能特异扩增CAV-2和CDV,不能扩增犬细小病毒、犬冠状病毒、犬副流感病毒、犬钩端螺旋体和犬黄胆出血群、狂犬病病毒。敏感性试验表明,所建立的双重PCR方法可以扩增4.63ng总核酸量。在上述试验基础上继续优化条件建立了能同时检测CAV-2和CDV两种病毒的双重PCR检测方法,并用该方法检测来自辽宁、吉林等15家动物医院134份鼻液和眼眵样品,与商品化试纸条检测结果相比,本方法更加敏感和方便。研究结果表明,本实验建立的方法敏感、特异,适用于动物犬瘟热病毒和犬腺病毒2型的快速检测和鉴别诊断。     

饲养密度与饲粮能量水平对肉仔鸡生长性能及肉品质的影响

本试验旨在研究饲养密度与饲粮能量水平对肉仔鸡生长性能及其肉品质的影响,并探明饲养密度是否影响肉仔鸡的能量需要量。选用 ２周龄体重相近的爱拔益加（ＡＡ）肉仔鸡１１４０只（公母各占 １／２）,采用 ３×４两因子完全随机试验设计,包括 ３个代谢能水平（１２．３３、１２．７５和 １３．１７ＭＪ／ｋｇ）和 ４个饲养密度（１０、１６、２２、２８只／栏）,随机分为 １２个处理,每个处理 ５个重复,设置 ６０个相同的围栏,分栏饲养,围栏有效面积为 １．５ｍ２。正试期 ２８ｄ。结果表明：１）饲养密度和饲粮能量水平影响肉仔鸡的生长性能,但两者之间不存在交互作用（Ｐ＞０．０５）;高密度饲养极显著限制肉仔鸡平均日采食量（Ｐ＜０．０１）,导致平均日增重极显著降低（Ｐ＜０．０１）,但不影响料重比（Ｐ＞０．０５）;高能饲粮极显著降低肉仔鸡料重比（Ｐ＜０．０１）,提高平均日增重和出栏体重（Ｐ＜０．０１）;２）饲养密度对肉仔鸡胴体品质和肉品质影响较小,但饲粮不同能量水平可造成脂肪酸在体内沉积的差异,胸肌中多不饱和脂肪酸、必需脂肪酸含量随饲粮能量水平提高而显著增加（Ｐ＜０．０５）;３）保持良好的饲养环境,饲养密度不会造成肉仔鸡明显的免疫应激差异（Ｐ＞０．０５）。综上所述,饲养密度和饲粮能量水平影响肉仔鸡生长性能,同时能量水平对肉品质造成较大影响。但在良好的饲养环境中,饲养密度并不影响肉仔鸡对能量的需要量,二者之间不存在交互作用。     

辽宁省复种青贮玉米潜力分析与技术探讨

分析了复种青贮玉米Zea mays对气候资源的利用特点、产量和品质优势以及市场需求,并根据田间试验结果提出了辽宁地区复种青贮玉米生产的4项关键技术,即：辽宁地区复种青贮玉米适宜的品种为郑单958和高油青贮4515;为保证产量和品质,选用郑单958和高油4515品种,播期最好不要超过7月19日;在有机质中等偏上、氮含量中等、磷和钾缺乏的土壤条件下,经济合理的施氮量为250 kg/hm2,施磷量(P2O5)为100 kg/hm2;采用穴播技术（一穴双株）可有效地提高产量,适宜的穴播密度为10万株/hm2。     

大豆胰蛋白酶抑制因子对獭兔氮平衡和养分消化率的影响

试验选择（63±4）日龄、平均体重为（1150.5±124.0） g的健康美系獭兔20只,随机分为5组,每组4只兔,公母各半。试验日粮分别含有25%生大豆、25%化学钝化大豆、25%热处理大豆、25%豆粕和13%生大豆+12%豆粕。胰蛋白酶抑制因子含量（实测值）分别为6.55、 1.99、1.73、 0.81和3.97 mg/g。试验结果表明,25%生大豆组显著降低饲料氮表观消化率（P<0.05）,显著增加粪氮排出（P<0.05）,对尿氮无显著影响;化学钝化、热处理及生大豆+豆粕组粪氮、氮消化率同豆粕组间无显著差异（P>0.05）。饲料干物质、有机物质、无氮浸出物、粗脂肪、粗纤维表观消化率5组间无显著差异（P>0.05）。     

鸡爪槭转色期叶色变化生理研究

以杭州植物园与花港观鱼公园的鸡爪槭(Acer palmatum Thunb)成龄植株为材料,测定10月下旬至12月上旬鸡爪槭转色期叶绿素、花色素苷和可溶性糖含量的变化,比较不同光照强度及温度对叶色的影响。结果表明:叶片中叶绿素含量随时间的变化逐渐降低,树冠背阴面叶片中的叶绿素含量显著高于向阳面,阳面东向显著高于阳面西向;花色素苷的含量则随时间不断升高,11月21日之后变化尤其显著;可溶性糖含量在11月21日之前迅速增加,之后趋于稳定。温度与叶绿素含量呈显著正相关,与花色素苷和可溶性糖含量成显著负相关。     

大棚土壤接种丛枝菌根真菌增强黄瓜枯萎病抑制水平

A pot experiment was conducted to study the plant growth and fruit yields of cucumber (Cucumis sativus L.) on a greenhouse soil with or without inoculation of arbuscular mycorrhizal fungi (AMFs) and Fusarium oxysporum f. sp. cucumerinum under unsterilized conditions. Two AMF inocula were tested: only one AMF strain Glomus caledonium 90036 and an AMF consortium mainly consisting of Glomus spp. and Acaulospora spp. There were four treatments including no inoculation (control), inoculation with F. oxysporum but without mycorrhizae (FO), inoculation with F. oxysporum and G. caledonium (FO+M1), and inoculation with F. oxysporum and the AMF consortium (FO+M2). Cucumber plants were harvested at weeks 3 and 9 after transplanting. Compared with the control, the FO treatment without AMF inoculation had less biomass both at weeks 3 and 9 (P < 0.05) and had higher incidence of Fusarium wilt and produced no cucumber fruit at week 9. Both FO+M1 and FO+M2 treatments had higher mycorrhizal colonization than the treatments which received no AMF inoculation at week 3 (P < 0.05), but only the FO+M2 treatment elevated plant biomass, decreased the incidence of Fusarium wilt, and improved cucumber yields to the same level as the control at week 9. The results indicated that the AMF consortium could suppress Fusarium wilt of cucumber and, therefore, showed potential as a biological control agent in greenhouse agroecosystems.     

甜菊醇糖苷生物合成途径关键酶基因KA13H的克隆及序列分析

本研究利用RT-PCR方法从甜叶菊叶片中分离了一个与甜菊醇糖苷生物合成密切相关的基因KA13H,对该基因的ORF、编码产物结构、同源性比对及次级结构等进行了生物信息学预测分析,同时初步分析该基因的组织表达和原核表达。经DNAMAN6.0软件分析,该基因编码一条分子量为54.476kD的由476个氨基酸残基组成的多肽,含有典型的细胞色素P450的血红素结合位点FXXGXXXCXG,TMPRED程序预测其C-端含有一个明显的跨膜区MIQVLTPILLFLIFFVFWKVY,是一个典型的细胞色素P450基因。推断的KA13H编码产物与其它生物合成相关细胞色素P450同源比对和系统发生分析表明,该蛋白与苜蓿(Medicago truncatula)CYP716A12和云杉(Sitka spruce)CYP720B1的一致性较高,分别为51%和46%,推测KA13H可能与CYP716A12和CYP720B1具有类似的功能。KA13H次级结构分析结果表明,KA13H与CYP74A2的一致性仅为15%,但是它们却有着类似的次级结构,都含有6个基质识别位点(SRSs)。半定量RT-PCR分析表明:KA13H在根、茎、叶和花中...     

Oxidative stress response and histopathological changes due to atrazine and chlorpyrifos exposure in common carp

Atrazine (ATR) and chlorpyrifos (CPF) are the most common pesticides found in freshwater ecosystems throughout the world. Herein, we investigated the oxidative stress responses and histopathological changes in the liver and gill of common carp after a 40-d exposure to CPF and ATR, alone or in combination, and a 20-d recovery treatment. We found that exposure to ATR, CPF or their mixture for 40 d could induce decrease in antioxidant enzyme (SOD, CAT and GSH-Px) activities and increase in MDA content in a dose-dependent manner in the liver and gill of common carp. Especially with regard to the pathological changes, the tissue damage increased in severity in a dose-dependent manner. The liver tissue of common carp revealed different degree of hydropic degeneration, vacuolisation, pyknotic nuclei, and fatty infiltration. The gills of common carp displayed varied degrees of epithelial hypertrophy, telangiectasis, oedema with epithelial separation from basement membranes, general necrosis, and epithelial desquamation. After a 20-d recovery treatment, the antioxidant enzyme activities and MDA content were significantly lower (p < 0.05) than in the corresponding exposure groups in all of the highest doses, but not in the lower doses. To our knowledge, this is the first report of subchronic oxidative stress and histopathological effects caused by ATR, CPF and their mixture in the common carp. Thus, the information presented in this study is helpful to understand the mechanism of ATR-, CPF- and ATR/CPF-mixture-induced oxidative stress in fish.