新疆棉花品种次生代谢酶活性与诱导抗蚜性的关系

为了明确不同棉花品种次生代谢酶活性与诱导抗蚜性的关系,研究了不同类型棉花品种在棉蚜为害胁迫下,苯丙氨酸解氨酶(PAL)、过氧化物酶(POD)和多酚氧化酶(PPO)活性的变化及其对抗蚜性的影响。结果表明,未受蚜害时不同品种同一酶活性存在显著差异;受蚜害诱导后,抗蚜品种和感蚜品种3种酶活性均有不同程度的上升,抗蚜品种酶活性显著高于感蚜品种,诱导抗蚜性的强弱在不同品种间差异显著。     

一种改进的尖孢镰刀菌的实时荧光定量PCR检测方法

为实现荧光定量PCR对土壤病原真菌数量更为高效、灵敏的检测,本研究将液体培养的孢子悬浮液和长年耕作的水稻土制作成孢子浓度为4×10~1~4×10~6 spore/g的带菌土,采用MoBio PowerSoil@DNA Isolation Kit提取模拟带菌土壤总DNA,引入常规PCR预扩增包含qPCR目标序列的1 446bp片段,以预PCR产物为模板进行qPCR,构建荧光定量PCR标准曲线。研究结果表明:以试剂盒提取的带菌土壤总DNA为模板绘制的qPCR标准曲线相关系数r为0.985,检测下限为4×10~3 spore/g土;引入预PCR后,qPCR标准曲线相关系数r为0.974,检测下限为4×10~2 spore/g土,较未引入时提高了10倍,结合不同土壤病原真菌的特异性引物,该检测方法可为土壤病原真菌的有效定量检测提供技术支撑。     

红砂优良种源选择及其地理变异规律

收集我国甘肃、宁夏、内蒙古等红砂天然分布区的23个种源的红砂种子,在武威市林业技术服务中心建立红砂种源试验。以23个种源的2 a、3 a生红砂苗木为研究材料,每个种源选取10个单株,测定叶片中可溶性蛋白(SP)、可溶性糖(SS)、脯氨酸(Pro)及叶绿素(Chl)相关指标,每个单株重复测3次。分析红砂苗期不同种源选择效果及其地理变异规律。结果表明:可溶性蛋白、可溶性糖、脯氨酸及叶绿素相关指标在23个红砂种源间存在丰富的变异,为优良种源的选择创造了条件。通过多重比较筛选出XGG(小甘沟)、ZZG1(扎子沟1)、ZZG2(扎子沟2)、JQGZ(酒泉瓜州)4个优良种源,入选率为17.39%。与其他种源相比较,XGG的可溶性糖含量在2 a和3 a生时都是最大,分别为13.13 mg·g~(-1)和15.54 mg·g~(-1);ZZG1的脯氨酸、叶绿素a、叶绿素b以及叶绿素(a+b)含量在3 a生时最大,依次为631.82μg·g~(-1)、595.40μg·g~(-1)、161.85μg·g~(-1)、757.25μg·g~(-1);ZZG2的脯氨酸含量在2 a和3 a生时排第2,为529.99μg·g~(-1)和622.87μg·g~(-1),叶绿素a/b值在3 a生时最大,为3.85;JQGZ的可溶性蛋白含量分别在2 a和3 a生时均最大,为9.63 mg·g~(-1)和7.66 mg·g~(-1)。通过相关性分析,发现红砂种源呈西北-东南抗旱性减弱的变异趋势。     

氮素化学形态及添加剂量对温带森林土壤N2O排放的影响

土壤中氮形态和氮剂量的有效性是影响土壤氧化亚氮(N₂O)排放的重要因子。为了提高氮素化学形态及添加剂量对温带森林土壤N₂O排放的影响,本研究在北京林业大学实验林场,以温带油松林土壤为研究对象,通过野外氮添加控制实验,采用静态箱/气相色谱法分析不同水平(对照,CK:0 kg/(hm2·a); 低氮,LN:50 kg/(hm2·a); 中氮,MN:100 kg/(hm2·a); 高氮,HN:150 kg/(hm2·a))和不同形态(混合态氮,AN:NH₄NO₃; 铵态氮,As:(NH₄)₂SO₄; 硝态氮,Na:NaNO₃)的氮添加对温带油松林土壤N₂O排放通量的影响。结果表明:氮添加处理样地N₂O排放表现出明显的季节性变化特征,排放高峰出现在6—8月,其他季节土壤N₂O排放通量相对较低,最小值出现在1月。不同氮添加处理均促进了土壤N₂O的排放:在不同水平的氮添加下,随着氮添加水平的增加,土壤N₂O排放通量也升高,表现为HN＞MN＞LN＞CK。不同形态的氮输入对N₂O排放的促进作用表现为:AN＞As＞Na,As添加与AN和Na添加没有显著差异(P>0.05),但AN添加与Na添加之间差异显著(P＜0.05)。此外,空气温度、土壤温度和土壤孔隙含水量也可以影响土壤N₂O的排放。年度土壤N₂O排放系数范围是0.34%~0.94%,年均排放系数为0.364%,低于联合国政府间气候变化委员会(IPCC)推荐的默认值。      

酶解牦牛血发酵液制备抗氧化肽工艺优化

为进一步提高牦牛血枯草芽胞杆菌发酵液多肽含量,对牦牛血发酵液进行酶解,以酶解液的·OH清除率、多肽含量为主要指标,筛选酶解发酵液的最适蛋白酶,通过单因素和响应面试验优化酶解工艺,并对比菌酶联合制备产物与发酵液体外抗氧化活性。结果表明,碱性蛋白酶酶解发酵液最佳条件为:酶解时间3 h、p H值9.5、酶解温度60℃和酶底比190 U·g-1,此条件下制备得到酶解液多肽含量为5.52mg·mL~(-1),较发酵液提高2.39倍。菌酶联合制备产物对·O2-及脂质过氧化的IC50分别为6.22、4.87mg·mL~(-1),发酵法制备产物对·O2-及脂质过氧化的IC50分别为8.42、11.71 mg·mL~(-1),且菌酶联合制备产物的还原力优于发酵制备产物。因此,菌酶联合制备牦牛血抗氧化肽法优于传统单一发酵法。本研究结果对提高牦牛血抗氧化肽得率,增加牦牛产品附加值具有重要的意义。     

间作两个生态气候区的龙葵和少花龙葵促进茄子幼苗生长且降低镉吸收

Soil contamination by heavy metals is a serious environmental problem worldwide,and reduction of heavy metal accumulation in vegetables grown on contaminated land is a matter of urgency.A pot experiment was conducted to study the effects of intercropping with the Cd hyperaccumulators Solanum nigrum and Solanum photeinocarpum from two ecoclimatic regions,Ya'an and Chengdu,Sichuan Province,China,on the growth and cadmium (Cd) uptake of eggplant (Solanum melongena L.).The biomass,photosynthetic pigment contents,and activities of antioxidant enzymes of eggplant were enhanced by intercropping.The biomass of eggplant was the highest after intercropping with S.photeinocarpum from Ya'an,but did not differ significantly from that after intercropping with S.nigrum from Chengdu.The shoot Cd content of eggplant was significantly reduced by intercropping with the hyperaccumulators,which ranked as follows:S.nigrum from Chengdu ＞ S.nigrum from Ya'an ＞ S.photeinocarpum from Chengdu ＞ S.photeinocarpum from Ya'an,with the decreases being 19.60％,14.36％,9.66％,and 6.42％,respectively,as compared with the control.The lowest shoot Cd content and translocation factor of eggplant were attained after intercropping with S.nigrum from Chengdu.Therefore,it was feasible to intercrop eggplant with S.nigrum and S.photeinocarpum on Cd-contaminated soil.     

二氧化碳升高与干旱对植物生理、土壤碳及土壤酶活的影响

Global climate models have indicated high probability of drought occurrences in the coming future decades due to the impacts of climate change caused by a mass release of CO2.Thus,climate change regarding elevated ambient CO2 and drought may consequently affect the growth of crops.In this study,plant physiology,soil carbon,and soil enzyme activities were measured to investigate the impacts of elevated CO2 and drought stress on a Stagnic Anthrosol planted with soybean (Glycine max).Treatments of two CO2 levels,three soil moisture levels,and two soil cover types were established.The results indicated that elevated CO2 and drought stress significantly affected plant physiology.The inhibition of plant physiology by drought stress was mediated via prompted photosynthesis and water use efficiency under elevated CO2 conditions.Elevated CO2 resulted in a longer retention time of dissolved organic carbon (DOC) in soil,probably by improving the soil water effectiveness for organic decomposition and mineralization.Drought stress significantly decreased C:N ratio and microbial biomass carbon (MBC),but the interactive effects of drought stress and CO2 on them were not significant.Elevated CO2 induced an increase in invertase and catalase activities through stimulated plant root exudation.These results suggested that drought stress had significant negative impacts on plant physiology,soil carbon,and soil enzyme activities,whereas elevated CO2 and plant physiological feedbacks indirectly ameliorated these impacts.     

1DSZ-350型悬挂式水田单侧旋耕镇压修筑埂机的设计与试验

为提高水田筑埂作业质量与效率,减轻作业劳动强度,结合东北地区水稻种植农艺要求,研究设计了1DSZ-350型悬挂式水田单侧旋耕镇压修筑埂机。阐述分析了机具整体设计方案与工作原理,对其关键部件偏牵引悬挂仿形调节系统、旋耕筑埂深度可调式传动总成、旋耕集土刀辊总成和镇压筑埂圆盘总成进行了理论分析与结构设计。为获得修筑埂机最佳工作参数组合,以机具前进速度和旋耕工作转速为试验因素,田埂平均坚实度和高度变异系数为试验指标,进行了多因素二次通用旋转组合台架试验,运用Design-Expert 6.0.10软件建立因素与指标间数学模型,采用多目标参数优化确定机具最佳作业状态。试验结果表明,当机具前进速度为1.33 km/h,旋耕工作转速为525 r/min时,筑埂作业性能最优,满足旋耕集土及镇压筑埂要求,其所筑田埂平均坚实度为2 160 k Pa,高度变异系数为4.01%。田间试验表明,该机具作业性能稳定,所筑田埂质量良好,各项指标均满足筑埂作业要求。该研究为水田机械化筑埂机具的创新研发与优化提供理论支撑和技术参考。     

一株奶山羊伪结核棒状杆菌的分离与鉴定

为获得陕西某羊场病羊脓包中的病原菌,以无菌采集的病羊颈部脓汁为材料,进行细菌分离培养,鉴定分离菌株的形态特征、培养特性、生化特性,挑取分离菌株进行协同溶血试验(cAMP)和16SrRNA基因的PCR扩增,并对序列进行分析,NJ法构建系统发育树;用分离菌株分别接种Balb/c小鼠和奶山羊;药敏试验鉴定分离株的耐药性。结果显示,分离菌株的形态特征、培养特性、生化特性与伯杰细菌鉴定手册所述伪结核棒状杆菌特性一致;测序显示分离菌株与GenBank中已收录伪结核棒状杆菌相似性达97%以上;Balb/c小鼠致病性试验和奶山羊动物回归试验表明分离株有强致病性;药敏试验表明分离菌株对红霉素、环丙沙星、克拉霉素、强力霉素、四环素、头孢唑啉、新霉素、氧氟沙星等多种抗生素敏感,对复方新诺明耐药。