[目的]明确黄帝陵侧柏叶枯病的病原菌及其培养特性,筛选对该病害具有较好防治效果的药剂,为黄帝陵古柏群的保护提供指导.[方法]采用组织分离培养法从采集的侧柏叶枯病叶中分离病菌,通过回接试验和柯赫氏法则,证明分离物是否为引起侧柏叶枯病的病原菌;通过形态学和分子生物学对黄帝陵侧柏叶枯病病原菌进行鉴定,并研究其在不同培养基上的生长速率;采用带毒平板法和田间试验筛选对黄帝陵侧柏叶枯病具有较好防治效果的药剂.[结果]经形态学和分子生物学鉴定,黄帝陵侧柏叶枯病病原菌为互隔交链孢(Alternariaalternata)和芍药生拟盘多毛孢(Pestalotiopsispaeoniicola),这2种病原菌可单独侵染,也可共同复合侵染.互隔交链孢和芍药生拟盘多毛孢在黄豆(SA)培养基和马铃薯蔗糖琼脂(PSA)培养基上生长速率均较高.室内抑菌活性测定结果表明,戊唑醇对互隔交链孢和芍药生拟盘多毛孢抑菌活性较高,其有效中浓度(EC50)分别为1.13和1.38 mg/L;咪鲜胺次之,其EC50分别为1.58和1.44 mg/L.田间试验结果表明,80％戊唑醇可湿性粉剂750倍液和25％咪鲜胺乳油3 000倍液对侧柏叶枯病的防效最佳,喷药4次后其防治效果均在80％以上.[结论]黄帝陵侧柏叶枯病由互隔交链孢(A.alternata)和芍药生拟盘多毛孢(P.paeoniicola)单独或共同侵染引起,为弱寄生菌,这2种病原菌均在SA和PSA培养基生长良好;侧柏为芍药生拟盘多毛孢(P.paeoniicola)的新寄主;戊唑醇和咪鲜胺对黄帝陵侧柏叶枯病具有良好的防治效果.
【目的】针对渭河流域咸阳-西安段的非点源污染状况,模拟分析不同管理措施下非点源污染负荷的削减效果,为渭河流域的非点源污染控制与治理提供科学依据。【方法】构建渭河流域咸阳-西安段的非点源污染SWAT模型,利用2008-2016年逐月径流、水质及CMADS气象数据集等资料,对SWAT模型进行率定及验证,分析研究区内非点源污染特征;针对2016年研究区内非点源污染状况,设定4种管理措施,模拟验证不同管理措施在渭河流域咸阳-西安段对非点源污染负荷的削减效果。【结果】构建了渭河流域咸阳-西安段的非点源污染SWAT模型,该模型对研究区域具有较好的适用性和可靠性;2016年研究区域非点源总氮（TN）和总磷（TP）负荷的入河量分别为7 654.0和626.5 t,主要集中在蓝田县、长安区、临潼区、鄠邑区、旬邑县以及彬县部分子流域;通过实施化肥减量、集中设置沼气池和加强水土保持等3项措施,可分别削减7.57%～29.11%、0.54%～32.85%和0.4%～23.12%的非点源TN负荷以及2.59%～15.99%、0.45%～28.65%和0%～39.79%的非点源TP负荷;将上述3种管理措施整合在一起的综合管理措施的削减效果较单一措施明显提高,其可削减9.98%～50.68%的非点源TN负荷和5.25%～52.84%的非点源TP负荷。【结论】渭河流域咸阳-西安段非点源污染的重点控制时段在汛期（6-10月）,重点控制区域是蓝田县、长安区、临潼区、鄠邑区、旬邑县以及彬县部分子流域;加强水土保持和化肥减量是有效控制该研究区域非点源污染的重要措施。
[目的]同时敲除苜蓿银纹夜蛾核型多角体病毒(AcMNPV)基因组的Ac148、Ac149、Ac150(Ac148-150)基因,检测敲除Ac148-150基因片段对AcMNPV复制和外源蛋白表达能力的影响,为基因功能鉴定和缩小杆状病毒基因组提供参考.[方法]利用Red/ET同源重组系统和rpsL-AMP反向筛选系统对Ac148-150基因进行敲除,得到敲除型杆状病毒质粒(KOAc148-150杆状病毒质粒),提取AcMNPV KOAc148-150杆状病毒质粒和野生型杆状病毒质粒,将其分别与报告基因表达载体共转染Sf9细胞,成功构建重组杆状病毒(野生型病毒vAcMNPV/GFP和缺失突变病毒vAc△148-150/GFP),测定2种重组杆状病毒的一步生长曲线并比较其差异.将2种重组杆状病毒感染Sf9细胞后,采用荧光显微镜观察GFP荧光细胞分布,用流式细胞仪检测GFP荧光强度,再通过SDS-PAGE和Western blot检测Ac148-150缺失突变体表达的GFP产量.[结果]菌落PCR结果表明,AcMNPV中Ac148-150基因敲除成功.缺失突变病毒vAc△148-150/GFP与野生型病毒vAcMNPV/GFP的一步生长曲线基本一致,说明Ac148-150缺失不影响病毒的复制.荧光显微镜观察和流式细胞仪分析结果表明,敲除Ac148-150对外源蛋白GFP分布和荧光强度未产生影响.SDS-PAGE和Western blot检测结果显示,缺失突变病毒vAc△148-150/GFP和野生型病毒vAcMNPV/GFP表达GFP蛋白产量基本一致.[结论]从AcMNPV基因组中同时敲除Ac148、Ac149、Ac150基因后,对病毒的复制和外源蛋白的表达能力无影响.
【目的】研究西瓜属6个主要变种的染色体核型特征,为西瓜属作物品种亲缘关系鉴定及新品种培育等提供细胞学参考。【方法】以西瓜属6个主要变种饲用西瓜（PI296341）、普通西瓜（黑崩筋）、黑籽瓜（内蒙黑中片）、红籽瓜（江西信丰）、黏籽西瓜（PI254723）、药西瓜（PI386015）的根尖为试验材料,采用常规制片法制片,对其染色体数目、核型和进化趋势进行分析,并对6个变种的亲缘关系进行聚类分析。【结果】西瓜属6个主要变种的染色体类型均为二倍体（2n=2x=22）,含有不同数量的m和M染色体;根据相对长度系数可知各变种包括L、M 2 、M 1 和s等4种类型,其中L型染色体在饲用西瓜（PI296341）、普通西瓜（黑蹦筋）、黑籽瓜（内蒙黑中片）、红籽瓜（江西信丰）、药西瓜（PI386015）中均有出现,只有黏籽西瓜（PI254723）中未见;s型染色体在红籽瓜和黏籽西瓜中未出现,在其他4个变种中均有出现。西瓜属6个主要变种染色体的平均臂比值为1.09～1.36,核型类型属1A型和1B型,核型不对称系数为52.20%～57.42%。西瓜属6个主要变种的染色体核型进化程度由高到低依次为黑籽瓜（内蒙黑中片）、黏籽西瓜（PI254723）、饲用西瓜（PI296341）、药西瓜（PI386015）、普通西瓜（黑蹦筋）和红籽瓜（江西信丰）。【结论】西瓜属6个主要变种的核型特征具有一定程度的差异,核型进化趋势总体由对称向不对称发展;在核型特征上,饲用西瓜与药西瓜、药西瓜与普通西瓜亲缘关系较近,而红籽瓜（江西信丰）与其他5个变种亲缘关系较远。
[目的]对1株分离自桃树枝的内生真菌N1进行分类鉴定与系统发育分析,探讨其深层发酵液的抗乳腺癌活性,为该菌资源的进一步开发利用提供依据.[方法]通过形态学特征和ITS rDNA序列对野生菌株N1进行分类鉴定;基于ITS1-5.8S-ITS2序列的变异程度对菌株N1遗传多样性进行分析;采用MTT法检测菌株发酵液石油醚、乙酸乙酯、正丁醇和甲醇提取物的抗乳腺癌活性;观察乙酸乙酯提取物不同作用时间下乳腺癌细胞的形态变化;采用LC-MS/MS对乙酸乙酯活性提取物的成分进行分析.[结果]根据菌株形态学和ITS rDNA序列特征,将该野生菌株N1鉴定为韦司梅拟盘多毛孢Pestalotiopsis vismiae;其ITS1-5.8S-ITS2序列总变异率为10.3％,表明韦司梅拟盘多毛孢在自然界中具有丰富的遗传多样性.菌株N1深层发酵液乙酸乙酯提取物对人乳腺癌MDA-MB-231细胞生长的抑制作用最强(P＜0.05),作用24 h的半数抑制浓度(IC50)为131.39 μg/mL,作用48 h时,细胞呈现凋亡状态.LC-MS/MS数据表征了其中的13个化学成分,确定了6种物质,对其他未能鉴定的7个物质的分子式进行了初步表征.[结论]获得了韦司梅拟盘多毛孢遗传多样性的基础信息,其深层发酵液乙酸乙酯提取物是发挥抗乳腺癌细胞的主要活性物质.
[Objective]Effect of grape line covering on vineyard micro-region ecology and fruit quality was investigated to establish cultivation management measures of vineyard ecology.[Method]In the wine grape producing areas in the eastern foot of the Helan Mountain in Ningxia,4 years old Cabernet Sauvignon was selected,and 3 treatments of line covering with grape branches (GB),line covering with corn straw (CS) and tillage (CK) were configured.The effects on air temperature and humidity,soil temperature and humidity,soil microorganism,and other micro-ecological environment conditions in the vineyard canopy were studied,and the fruit quality was compared.Principal component analysis (PCA) was used to evaluate quality of grape and select suitable cultivation measures.[Result]Mulching significantly reduced soil temperature as well as air temperature and humidity.At soil depth of 0 to 20 cm,the average temperatures in July,August,and September in GB,CS and CK treatments were 22.4,21.8 and 24.6℃,and the microbial biomass amounts were 604.71×104,599.86×104 and 440.11×104 CFU/g,respectively.Compared with CK,GB and CS increased reducing sugars by 8.2％ and 6.8％,soluble solids by 15.6％ and 12.3％,and total acids by 8.3％ and 10.0％.In addition,the accumulation of anthocyanins and phenols in grape skin was increased.The grape quality scores of GB,CS and CK treatments evaluated by principal component analysis were 1.56,0.70 and-2.26,respectively.[Conclusion] Line covering can improve the vineyard micro-domain ecological environment and the quality of wine grape,and the GB coverage had the best effect.
[目的]研究北方地区玉米主产区骨干自交系籽粒干物质积累的过程(即籽粒灌浆过程),为优良自交系的选育提供依据.[方法]选用北方地区10个玉米骨干自交系(中早熟自交系A187,中熟自交系郑58、PH4CV、J9D207、KWCB1、KWMM31、HM12111,中晚熟自交系PH6WC,晚熟自交系昌7-2、M5972),研究骨干自交系百粒质量及灌浆速率的差异;应用Logistic模型对骨干自交系的籽粒灌浆过程进行拟合,比较不同自交系的灌浆参数;然后采用通径分析,研究百粒质量与灌浆活跃期和灌浆速率的关系.[结果]玉米自交系干物质积累随着授粉后时间推移而增加,呈“慢-快-慢”趋势.郑58的百粒质量在授粉后65 d最大、其次为HM12111、A187.10个骨干自交系灌浆速率差异显著,授粉后20～35 d的灌浆速率均值明显高于其他时间.Logistic模型较好地拟合了籽粒灌浆过程,确定了各骨干自交系的灌浆渐增期、快增期和缓增期.玉米骨干自交系百粒质量受灌浆速率和灌浆时间的影响,其中灌浆速率起决定作用.各骨干自交系百粒质量主要在灌浆快增期增加.灌浆活跃期及不同时期灌浆速率均对百粒质量有正向效应,其中灌浆快增期平均速率对百粒质量的正向效应最大.[结论]10个骨干自交系的平均灌浆速率以郑58、HM12111和A187较大,可在杂交种组配时充分合理地加以利用;通过提高灌浆快增期和渐增期平均速率,确保灌浆活跃期,相对延长快增期持续时间,可达到提高产量的目的.
[Objective]A new large-span asymmetric plastic greenhouse was designed and built to provide corresponding ideas for the development and design of new shed.[Method]According to the span size and number of covering layers,five tested greenhouses including 17 m span single-layer plastic greenhouse(17-1),17 m span double-layer plastic greenhouse(17-2),18 m span single-layer plastic greenhouse(18-1),18 m span double-layer plastic greenhouse(18-2),and 20 m span single-layer plastic greenhouse(20-1)were selected.Continuous temperature monitoring and comparison of temperature,soil temperature and illumination environment under typical sunny,cloudy and snowy days were carried out in the experimental greenhouses with the traditional arch plastic greenhouse and the Chinese solar greenhouse(CSG)as the control.[Result]①From December 01,2017 to January 31,2018,the average minimum temperatures in the winter of 18-1,18-2,17-1,17-2,and 20-1 were 4.1,4.9,-1.9,0,and-1.8℃,and the average maximum temperatures were 31.7,27.8,32.6,31.9,and 33.9℃ respectively.②Under typical sunny conditions,the minimum temperatures of 18-1,18-2,17-1,17-2 and 20-1 were 4.4,5.0,-3.4,-2.6,and-3.1℃,and they were 11.6,12.2,3.8,4.6,and 4.1℃ higher than outside,10.5,11.1,2.7,3.5,and 3.0℃ higher than arch plastic greenhouse and 6.3,5.7,14.1,13.3,and 13.8℃ lower than solar greenhouse.Under typical cloudy conditions,the minimum temperatures were 6.3,7.5,1.0,1.6,and 1.7℃,which were 8.4,9.6,3.1,3.7,and 3.8℃ higher than outdoor temperatures,7.7,8.9,2.4,3.0,and 3.1℃ higher than arch plastic greenhouse,and 5.4,4.2,10.7,10.1,and 10.0℃ lower than solar greenhouse,respectively.Under typical snow conditions,the minimum temperatures were 4.9,6.0,-2.7,-1.0,and-1.4℃,which were 10.7,11.8,3.1,4.8,and 4.4℃ higher than outdoor temperatures,10.0,11.1,2.4,4.l,and 3.7℃ higher than arch plastic greenhouse,and 5.0,3.9,12.6,10.9,and 11.3℃ lower than solar greenhouse,respectively.Under typical sunny conditions,the average soil temperatures of 18-1,18-2,17-1,17-2,and 20-1 were 12.2,12.3,10.0,11.1,and 9.6℃,which were 6.0,6.1,3.8,4.9,and 3.4℃ higher than arch plastic greenhouse.Under typical snowy conditions,the average soil temperatures were 11.9,12.1,9.5,10.6,and 9.6℃,which were 5.8,6.0,3.4,4.5,and 3.5℃ higher than arch plastic greenhouse.Under typical cloudy conditions,the average soil temperatures were 11.2,11.4,9.9,10.5,and 9.5℃,which were 5.4,5.6,4.1,4.7,and 3.7℃ higher than arch plastic greenhouse.③Comparison of temperature and light distribution between the north and south of the experimental greenhouse showed that the temperature in each test greenhouse was the highest in the middle,followed by the south and the north.The temperature distribution in the greenhouses was in the order of 17-1＞18-1＞20-1＞18-2＞17-2.The experimental greenhouses had the best light in the south,slightly lower in the middle and the worst in the north.The light transmittance was in the order of 18-1＞18-2＞20-l＞17-l＞17-2.[Conclusion]Comprehensively considering thermal and light environment,18 m double-layer asymmetric greenhouse had good thermal insulation performance,minimum average temperature and high average soil temperature without extreme low and high temperature.The north and south temperature and light distribution had small difference,the transmission rate was high,and it was more suitable for promotion and application.
【目的】探究烘烤过程中带茎烟叶水分迁移特性,为揭示带茎烘烤烟叶干燥机理提供参考。【方法以"云烟87"上部叶为试验材料,利用质外体染色示踪法、阿贝折射仪法及核磁成像技术,研究烘烤过程不同带茎位置和不同带茎长度条件下烟叶水分的迁移、状态和干燥特性。【结果】主脉木质部导管与茎秆形态学下端木质部导管相连接,带茎烘烤过程中烟叶位于茎秆形态学上端时,有利于茎秆中的自由水经茎秆形态学下端木质部导管进入主脉木质部导管向叶片迁移,进而显著延缓叶片和主脉组织水分散失,随着带茎长度的增加延缓作用更明显。烘烤过程中带茎烟叶主脉木质部导管迁移速率逐渐降低,与鲜烟叶相比,42和54℃主脉水分迁移速率分别减小75%和94%,主脉木质部导管由叶基至叶尖水分迁移速率也呈降低趋势。烟叶位于2cm长的茎秆形态学上端时,烘烤后期主脉部分水分向茎秆迁移,有利于烟叶的干叶和干筋。【结论】带茎烘烤过程中烟叶位于茎秆形态学上端时,随着带茎长度的增加延缓烟叶干燥的作用增强。
【目的】研究产卵时段和培养温度对似士维螨（Schwiebea similis Manson（蜱螨目:粉螨科））亲代雌螨生殖力、子代性比率和世代期的影响,为防治西洋参新害虫提供理论依据。【方法】采用二因素试验设计,因素A为亲代雌螨群产卵时段,设3个水平,分别为每批34头亲代雌螨在夜间产卵12h（N12h）、白天产卵12h （D12h）、昼夜产卵24h（DN24h）;因素B为培养温度（T）,设9个水平,分别为11.0,12.0,14.9,17.7,21.0,23.7,27.1,30.0和33.0℃。将子代卵、幼螨和若螨用群体培养法培养,统计各有效组合内子代雌、雄螨数及世代期,计算亲代雌螨均殖数（PCR）、子代性比率和世代期均值（N）,并使均值服从方差分析;计算世代发育起点温度（C）和有效积温（K）,并组建N与T间的倒数模型。【结果】亲代雌螨昼夜产卵,由此2时段内所产卵粒育活的子代成螨数近似,PCR均值间差异不显著（P＞0.05）。在11.0～27.1℃,子代全螨PCR均值达13.9头/d,而在23.7℃最高为16.2头/d。产卵时段和培养温度对子代雌雄性比率都无显著影响（P＞0.05）,均值1.10,有波动但无定向偏差。培养温度对子代成螨世代期的影响极显著（P＜0.01）,世代期随温度的上升而骤降。子代全螨世代期N与温度T间的倒数模型为:N=K/（T-C）=（184.3±4.55）/[T-（8.43±0.28）];估算此螨在当地发生6～9代/年。【结论】昼夜节律不影响似士维螨的产卵习性,亲代雌螨均殖数显示其有高产特例,子代雌雄性比率反映其种群结构,而倒数模型揭示其生理学时期,并为估算其田间种群增长趋势提供基本参数。
【目的】建立黄瓜高频胚状体再生体系,为黄瓜遗传转化体系的完善奠定基础。【方法】以黄瓜品种津研四号、长春密刺、Q8和14-1为材料,研究不同基因型材料愈伤组织的诱导情况;分别取14-1的子叶、子叶节、下胚轴和成熟胚为外植体,研究不同外植体类型的愈伤组织和胚状体产生情况;以14-1子叶节为外植体,研究不同激素及其质量浓度配比对黄瓜胚状体诱导的影响。【结果】4个不同基因型中,欧洲温室型黄瓜种质14-1可诱导出胚状体。在4种外植体类型中,14-1的子叶节可以高效诱导出愈伤组织和胚状体,其诱导率分别为100.0%和34.1%。激素及其质量浓度组合也会影响胚状体的诱导,在愈伤组织诱导阶段,以MS+1.5mg/L 2,4-D为培养基对胚性愈伤组织的诱导效果最好,其对14-1子叶节的诱导率为100%;在分化培养阶段,MS+0.1mg/L 2,4-D+0.5mg/L KT+0.2mg/L IAA有利于体细胞胚的发生,14-1的出胚率为62.5%。显微形态观察发现,黄瓜体细胞胚发育过程包括球形胚、心形胚、鱼雷胚和子叶期胚等时期,这些胚可以发育成正常小植株。【结论】14-1的子叶节经诱导培养基MS+1.5mg/L 2,4-D和分化培养基MS+0.1mg/L 2,4-D+0.5mg/L KT+0.2mg/L IAA培养后,可高效产生胚状体,并可萌发成正常植株。
[目的]分离筛选具有抑菌、降解纤维素及抗氧化等功能的亳菊内生菌,为其在农业上的开发应用奠定基础.[方法]以株龄9个月的安徽亳菊为材料,分别取根、茎、叶、花4部分,采用平板培养法从中分离内生菌菌株,并在平板上筛选和检测分离菌株对玉米弯孢菌、黄瓜枯萎菌、小麦赤霉菌、串珠镰刀菌、瓜炭疽菌、茶叶轮斑菌等6种植物病原菌的抑菌活性,测定目标菌株BJF10对纤维素的降解活性和DPPH的清除能力,根据菌体形态特征和ITS序列系统发育树对菌株BJF10进行鉴定.[结果]从亳菊的根、茎、叶、花中共获得了56株内生菌菌株,其中菌株BJF10对6种植物供试病原菌均有较强的拮抗作用,抑菌率均在5o％以上;菌株BJF10培养第4天的纤维索降解活性达到最强,培养3d时羧甲基纤维素酶(CMCase)和滤纸酶(FPase)的活力达到最高,分别为180.32和81.46U/mL;BJF10的7d培养上清液对DPPH的清除率可达67.7％;根据形态特征及ITS序列的系统发育分析,将菌株BJF10鉴定为柄孢壳菌属(Zopfiella sp.).[结论]柄孢壳菌属亳菊内生真菌BJF10菌株具有拮抗植物病原菌、降解纤维素、抗氧化等生物活性.
[目的]为提高分离自藏灵菇的鼠李糖乳杆菌zrx01产细菌素的能力,对其产细菌素的发酵条件进行优化,并分析其抑菌活性.[方法]采用单因素试验,分析鼠李糖乳杆菌zrx01产细菌素的最适发酵条件,即发酵时间、温度、培养基初始pH值、接种量等4个因素对其产细菌素能力的影响,在此基础上利用Box-Behnken法设计四因素三水平正交试验进行响应面优化,利用优化条件提取细菌素并对大肠杆菌进行抑菌试验.[结果]响应面法优化的鼠李糖乳杆菌zrx01产细菌素的最佳发酵条件为发酵时间20 h、发酵温度35℃、培养基初始pH6.5、接种量2.5％(体积比),此时细菌素的相对效价为(242.02士10.24)AU/mL,比优化前的相对效价(118.40±10.36)AU/mL提高了104.41％.获得的发酵上清液用乙酸乙酯萃取浓缩,作用于大肠杆菌指示菌和鼠李糖乳杆菌zrx018h,鼠李糖乳杆菌zrx01不产生抑菌圈,而大肠杆菌抑菌圈明显.扫描电镜显示,该细菌素对鼠李糖乳杆菌zrx01自身无作用,但可使大肠杆菌的菌体表面形成孔洞,从而抑制大肠杆菌的生长.[结论]分离自藏灵菇中的鼠李糖乳杆菌zrx01所产细菌素,在食品防腐方面具有很好的应用前景.
[目的]以江淮地区麦茬稻田为对象,研究秸秆还田下不同施肥处理对稻田N2O和CH4排放的影响,并结合水稻产量计算不同处理综合温室效应(GWPs)和温室气体强度(GHGI).[方法]试验采用裂区设计,主处理2个水平,为秸秆还田(S)和秸秆移除(NS),副处理4个水平,分别为不施氮肥(CK)、传统施肥(T0)、生物炭与尿素配施(T1)和单施硫酸铵(T2),共计8个处理,采用静态暗箱-GC气相色谱法检测不同处理稻田N2O和CH4排放通量,测定土壤温度、湿度和无机氮含量,统计水稻产量,计算综合温室效应和温室气体强度.[结果]无论是秸秆还田还是移除条件下,除CK外,其他施肥处理的N2O和CH4排放通量都会在基肥和追肥施用后出现峰值.无论秸秆还田与否,与传统施肥处理相比,生物炭与尿素配施和单施硫酸铵处理均能显著降低NzO和CH4累积排放通量.在秸秆还田和移除条件下,与传统施肥处理相比,生物炭与尿素配施处理均会导致水稻产量显著降低,但会提高土壤NO3-含量,增加对周围水体污染的风险.在秸秆移除和还田条件下,与传统施肥处理相比,单施硫酸铵均能显著增加水稻产量,增幅分别为12.27％和7.78％.与秸秆移除相比,秸秆还田条件下单施硫酸铵会显著促进N2O排放,但显著降低CH4的排放以及综合温室效应和温室气体强度.[结论]在目前秸秆还田造成CH4排放增加的背景下,用硫酸铵替代尿素能显著降低CH4排放,并提高水稻产量,降低综合温室效应,施用效果最佳.
[Objective]The objective of this study was to investigate the effects of fall dormancy on yield,nutritive value and winter surviving rate of different alfalfa varieties for selecting proper alfalfa varieties in Hohhot and surrounding areas.[Method]Five alfalfa varieties were selected and sowed in Helinger on May 20,2014.The growth and winter surviving rates were observed from 2015 to 2017,and dry matter (DM),crude protein (CP),acid detergent fiber (ADF) and neutral detergent fiber (NDF) were analyzed.Fresh yield,hay yield and relative feed value (RFV) were calculated.The optimal alfalfa variety was determined based on hay yield and RFV.[Result]Alfalfa varieties with lower fall dormancy levels had later returning green time in spring,while those with higher fall dormancy levels had lower winter surviving rates.The three years averaged fresh yield and hay yield of the five varieties had very significant difference (P＜0.01).The fresh yield and hay yield of Gold empress were the highest and very significantly higher than that of other varieties (P＜0.01).Caoyuan No.3 had the highest CP and RFV,but the lowest ADF and NDF.ADF and NDF of Caribou was very significant higher than other alfalfa varieties (except ADF of the Gold empress) (P＜0.01).Caoyuan No.3 and Gold empress were better than other alfalfa varieties.[Conclusion]There was significantly negative correlation between fall dormancy and winter surviving rate.The varieties of Gold empress and Caoyuan No.3 with fall dormancy levels of 1-3 had better fresh yield,hay yield,winter surviving rate and nutrition over the three years,and they were suitable for planting and promotion in Hohhot and surrounding areas.
[目的]掌握河南地区猪源性大肠杆菌的耐药情况及不同的耐药基因类型,为临床防治用药提供依据.[方法]以从河南地区规模化猪场中分离鉴定的23株大肠杆菌为研究对象,选用21种抗生素药物对大肠杆菌耐药性进行分析,用PCR方法对耐药质粒DNA进行扩增,并对氨基糖苷类(aac(3)-Ⅳ、aph(3')-Ⅱ)、四环素类(tetD、tetB)、β-内酰胺类(TEM、SHV)、大环内酯类(ermB、ermC)等4类耐药基因型进行检测.[结果]23株致病性大肠杆菌对抗生素类药物均有不同程度的耐药性,其中对青霉素、红霉素、四环素、卡那零素、多西环素、氟哌酸、氨苄西林等7种抗生素的耐药性较强,耐药率分别为100.0％,91.3％,86.9％,78.2％,78.2％,73.9％和73.9％,且均在70％以上.23株大肠杆菌检出的耐药基因包括氨基糖苷类aac(3)-Ⅳ和aph(3')-Ⅱ、四环素类tetD和tetB及β-内酰胺类SHV、大环内酯类ermC等6个基因型,其与GenBank数据库中相关序列的同源性均在97％以上,未检出TEM和ermB.[结论]河南地区大肠杆菌耐药基因类型多而复杂,耐药性严重并存在多重耐药性.
[目的]探讨择伐强度对云冷杉天然次生林空间结构的影响,为天然林空间结构优化提供依据.[方法]在吉林省汪清县金沟岭林场,选择不同择伐强度(0％,20％,30％,40％)的典型云冷杉天然次生林各设置3块样地,根据样地中林木坐标点图构建林分的Voronoi图,同时建立TIN三角网,结合Voronoi图结点距离判定对样地进行边缘校正,利用角尺度、昆交度、竞争指数、林木点密度、林层指数和开阔比数6个空间结构参数,对比分析不同择伐强度下云冷杉天然次生林林分及林分中云杉、冷杉、红松、紫椴、枫桦等5个主要树种的空间结构变化.[结果]择伐对云冷杉林分空间分布格局影响不大,择伐后10年各林分处于均匀分布状态,5个主要树种亦呈均匀分布.不同择伐强度云冷杉林分的平均混交度为0.630～0.716,林分处于强度混交状态,其中40％择伐强度下林分的混交度最高,20％择伐强度次之,5个主要树种均属强度或极强度混交.采用竞争指数和林木点密度分析不同择伐强度下云冷杉林分的林木竞争压力,得到相似的排序结果,均为0％＞30％ ＞40％＞20％,可知择伐强度20％林分的竞争指数和林木点密度皆小于其他样地,林分所受竞争压力最小,有较大的生长活力,其中冷杉作为优势种所受竞争压力较大.各林分中林木大部分位于中上层,林分整体垂直分层较单一,择伐强度30％林分的林层指数为0.398,林层丰富度高于其他林分,冷杉、红松、云杉多占据林分上层.不同择伐强度云冷杉林的平均开阔比数为0.712～0.743,林分整体处于开阔状态,其中择伐强度20％林分的开阔比数高于其他林分,说明择伐强度20％林分内光照条件和透光性优于其他林分;各林分中红松、冷杉、云杉开阔比数均较高,紫椴、枫桦开阔比数均较低.[结论]择伐强度20％云冷杉林分的状态整体优于其他林分,择伐强度30％林分的垂直层次丰富度较高,因此云冷杉天然次生林采伐强度在20％～30 ％较合理;另外需结合实际情况对林分进行补植,补植选择中心木附近且将角尺度调整为0.5左右,建议补植云杉、红松.
[Objective] Impacts of both rearing temperature and initial density on survival rate and fecundity of parental adults and feeding amount of filial new-adults of the pot-worm 9 Enchytraeus bulbosus Nielsen & Christensen (Clitellata:Enchytraeida:Enchytraeidae) were studied to extend its biological theories and estimate the level of damages and losses of American ginseng,Panax quinque folium L.,caused by the new pest.[Method]A two-factor experiment was designed in that nine gradients of constant temperature interacted with three levels of initial density of parental new-adult inoculations,and a full generation of the pot-worm was reared and observed.A total of six indexes were extracted,and an ANOVA was per-formed to determine effects of multiple treatments.[Result] Rearing temperature (T) exerted significant impact on survival rate (SR) of parental adults,rearing period (RP),adult equivalent (AE) of the first filial offspring,per capita reproduction (PCR) by parental adults,and daily mean reproduction (DMR) by parental adults.SR averaged at 87.1％ in the range of 12.0-30.1℃,but reduced significantly at 9.9 and 33.0℃.RP shortened rapidly with T of 9.9-30.1℃.The mean was 64.3,and mean PCR was 35.9 in 9.9-27.1℃,and both lowered significantly at 30.1℃.DMR increased with T significantly,reached the peak at 27.1℃,and then declined sharply.T had little influence on feeding amount (FA) of the first filial new-adults on fresh ginseng tissues,and mean FA was fresh mass 1.19 mg ginseng root powders per AE.Initial density (N0) exerted significant impact on RP,AE,PCR,DMR and FA,but showed little influence on SR.AE increased significantly with N0.As decreased with AE significantly,the trend of PCR or DMR revealed crowding effect among the first filial individuals.As declined with AE significantly,the trend of FA meant strong competition of food in the first filial progenies,and contributed to loss coefficients of American ginseng root.[Conclusion] SR,AE,PCR and DMR reflected the characteristics of pot-worm parental adults to survive and reproduce,whereas FA revealed feeding amount by filial new-adults on American ginseng root.These indexes can be used to estimate the pot-worm's populations and the damages to ginseng in the field so as to forecast and control the pest efficiently.
[目的]研究苹果砧木枝条主要输导组织解剖特征与矮化性的关系,探讨苹果砧木致矮关键部位.[方法]以不同矮化性的M系苹果砧木植株为试材,以MM106为对照,采用常规石蜡切片法,研究苹果砧木1年生枝各组织尤其是主要输导组织解剖特征与矮化性的关系.[结果]对于苹果砧木1年生枝横截面上不同部位的木质部,导管密度大小顺序均表现为近髓部＞中部＞近皮部,导管面积均表现为近皮部与中部差异不显著,但二者显著大于近髓部;M系苹果矮化砧木1年生枝的周皮厚度、皮层厚度、髓部半径、筛管面积均小于或显著小于对照,而导管平均密度、木质部厚度/枝条半径、近皮部导管面积/筛管面积、中部导管面积/筛管面积、近髓部导管面积/筛管面积、导管平均面积/筛管面积均大于或显著大于对照.[结论]对于苹果砧木1年生枝的木质部,从近皮部到近髓部,离髓部越近,导管密度越大、面积越小;M系矮化砧木1年生枝木质部发达,韧皮部生长较弱,M系苹果矮化砧木的致矮关键部位可能是韧皮部.
[目的]探究近年来乌蒙半细毛羊出现贫血、黄疸及血尿等症状的病因,为相关疾病防治提供参考.[方法]将出现患病羊的贵州省威宁县牛棚镇牧场作为试验牧场,贵州省赫章县凉水沟种羊场作为对照牧场,分别采集2个牧场的土壤、牧草样品,以及患病乌蒙半细毛羊(20只)与健康乌蒙半细毛羊(20只)的颈静脉血及肝脏,测定Cu、Mo、Mn、Co、Se、P、Fe和Zn含量,同时测定试验羊血液中SOD、CAT、GSH-Px、CPK、GOT活性和CP、MDA、Hb含量及RBC、MCHC、MCV、PCV、MCH、WBC等指标;然后将健康乌蒙半细毛羊转移到试验牧场上放牧,10 d后进行钼酸铵补充试验,设0,100,200,300 mg/kg 4个处理,测定乌蒙半细毛羊血液和肝脏中铜含量的变化情况,分析钼元素的影响.[结果]试验牧场土壤中的铜含量极显著高于对照牧场(P＜0.01),属于铜污染土壤;试验牧场牧草中的铜含量极显著高于对照牧场牧草(P＜0.01),且试验牧场牧草中铜钼比高于动物饲粮中的铜钼比正常值;患病乌蒙半细毛羊血液和肝脏中的铜含量极显著高于健康羊(P＜0.01),其他元素含量间无显著性差异;患病乌蒙半细毛羊血液中的SOD、CAT和GSH-Px活性极显著低于健康羊(P＜0.01),CPK、GOT活性和CP、MDA含量极显著高于健康羊(P＜0.01);患病乌蒙半细毛羊血液Hb、RBC和MCHC极显著低于健康羊(P＜0.01),MCV极显著高于健康羊(P＜0.01),PCV、MCH和WBC与健康羊无显著性差异(P＞0.05).将健康乌蒙半细毛羊在试验牧场饲养后,出现了与患病乌蒙半细毛羊相同的症状,补充钼元素后,这些羊血液和肝脏中的铜含量明显降低,到试验结束时,体内铜含量恢复到正常范围,病症消失,且以每10 d补充300 mg/kg钼酸铵2次的效果最好.[结论]乌蒙半细毛羊的慢性铜中毒症状是采食含铜量过多的牧草造成的,在饲粮中补充300 mg/kg的钼酸铵,可以有效缓解相关症状.
