极端高温对木薯单爪螨保护酶活性的影响研究

为探讨木薯单爪螨的生态适应性机理,揭示其种群扩散蔓延机制。本研究开展了极端高温胁迫对木薯单爪螨各龄螨的存活率及几种保护酶（多酚氧化酶PPO、过氧化物酶POD、抗坏血酸过氧化物AsA-POD、过氧化氢酶CAT和超氧化物歧化酶SOD）活性的影响研究。结果表明：经42℃高温处理,木薯单爪螨各龄螨最多仅可存活66 h,不能进一步发育。PPO和CAT活性在幼螨体内显著下降,而在前若螨到成螨却显著升高,而尤以前若螨升高最高;与对照相比,AsA-POD活性在幼螨体内无变化,但在前若螨体内可升高达对照的3.286倍,到后若螨期升高至对照的1.923倍,成螨期无显著变化;各龄螨体内POD和SOD的活性均无显著变化。因此,说明PPO、CAT和AsA-POD活性变化可能在木薯单爪螨抵抗高温过程中具有重要作用。     

生态补偿实现机理探讨

生态补偿是促进生态环境保护的一种经济激励手段。在对多元化的生态补偿概念进行阐述的基础上,结合生态补偿产生的经济学原理,给出影响生态补偿实现机理的相关性分析。结合因子间的相互联系,论述生态补偿实现形式多样化的原因。结合制度理论相关知识,对生态补偿实现机理进行深层次阐述。在对生态补偿政策方针指标适用维度进行分析的基础上,给出推荐的生态补偿政策方针。探讨性给出生态补偿实现框架,并针对实施层面可能出现的问题,给出进一步的完善策略。     

中黑盲蝽在转Bt基因棉和常规棉上的实验种群生命表

为比较两个转Bt基因棉品种99B和鲁93-2与一个传统非转基因棉品种春矮早对中黑盲蝽的抗性差异,在室内25±1 ℃、85%±5%RH和自然光照条件下,测定各品种上中黑盲蝽的发育历期、存活率和产卵量,组建了特定年龄生命表,并在田间笼罩内测定成虫对各品种的产卵选择性.结果表明:在春矮早上,中黑盲蝽的卵期和若虫期最长,卵孵化率、1龄若虫存活率、羽化率及雌成虫的产卵量最低.中黑盲蝽在春矮早上的种群趋势指数4.35、净增殖率3.68和内禀增长率0.04,均比其它两个品种的相应参数低.棉花苗期和盛花期,春矮早上的成虫落居量和落卵量均显著低于99B和鲁93-2上的同期水平.表明非转基因棉春矮早对中黑盲蝽的不选择性和抗性均较99B和鲁93-2强.     

寄主植物对B型烟粉虱个体发育和种群繁殖的影响

同一原始种群B型烟粉虱[Bemisia tabaci(Gennadius)],分别在甘蓝、一品红、棉花、番茄和黄瓜连续隔离饲养大约20代后形成5种对应的烟粉虱种群,研究其在甘蓝上各虫态大小、存活率、发育历期、成虫寿命和平均产卵量等生物学参数。在(25±1)℃条件下,一品红种群烟粉虱的1、2、3龄若虫体长和宽均显著低于其他4个种群烟粉虱;发育时间以甘蓝和一品红种群烟粉虱(20.44、19.69d)显著高于番茄种群烟粉虱(19.13d);雌虫寿命以甘蓝种群烟粉虱显著低于一品红、棉花、番茄和黄瓜种群烟粉虱;平均单雌产卵量以一品红种群烟粉虱(169.30粒)显著高于其他4个种群烟粉虱;5个种群烟粉虱在甘蓝上的总存活率均无显著差异。     

内江市畜牧业现状分析及发展对策研究

近年来内江市畜牧业得到了持续快速发展,畜牧业占农业总产值的比例达50%,但是还存在小生产与大市场的矛盾,畜牧业产业化经营程度低等问题,今后应该进一步加强对从业人员的培训,强化畜产品质量安全监管,加大对龙头企业的扶持力度,建立与国际接轨的畜产品质量标准体系。     

Lead (Pb) accumulation,oxidative stress and DNA damage induced by dietary Pb in tilapia (Oreochromis niloticus)

With the increasing occurrence of dietary lead (Pb) contamination in aquaculture, a better understanding of the toxic effects of dietary Pb on aquatic animals is needed. Tilapia (Oreochromis niloticus) were exposed to dietary Pb at concentrations of 0, 100, 400 and 800 μg g^?1 dry weight for 60 days, and Pb accumulation in tissues and blood, oxidative stress in posterior kidney and DNA damage in peripheral blood cells were investigated. The results showed that dietary Pb exposure resulted in significant Pb accumulation in tissues and blood, which increased with the dietary Pb concentrations. Pb accumulated in sampled tissues in the following order: posterior kidney>bone>liver>gill>spleen>testis>muscle>brain. Dietary Pb caused a significant increase in the malondialdehyde level and a significant decrease in the total antioxidant capacity content when compared with the control group (P<0.05), accompanied by concentration‐dependent decreases in the glutathione content, glutathione peroxidase and superoxide dismutase activities. Pb dose‐dependent DNA damage was observed in peripheral blood cells of tilapia exposed to dietary Pb. The results suggest that dietary Pb exposure can induce significant Pb accumulation in tissues and blood, followed by oxidative stress in posterior kidney and DNA damage in peripheral blood cells of tilapia.     

A dead-end filtration method to remove particle-associated pathogens in aquaculture systems

To reduce the incidence of bacterial diseases in recirculating aquaculture systems, 27 marine bacterial species were introduced into Instant Ocean maintained at 25°C. Those species were enumerated before and after filtration to evaluate the efficiency of the filtration procedure. The effects of sari filter and nylon filter on the survival of sea bass challenged with Vibrio alginolyticus were also determined. The results of laboratory studies indicated that the ability to remove pathogens was typically 1–3 log orders. Above 90% Vibrio sp., i.e., which were attached to particles, were removed by either 20-μm nylon net or four layers of sari. A 9.53% mortality of sea bass was reported in pilot filtration test using sari material as an end filter, while this percentage increased to 33.35% in control groups. It is concluded that a simple filtration procedure that involves the use of four-layer sari material can reduce the numbers of pathogens attached to particles in aquaculture system. The results of this study provide the basis for pathogen reductions in full-scale facilities.     

林业行业培训需求调查分析与思考

通过对林业从业人员和涉林专业在读学生的林业行业培训需求调查分析,结果表明：当前林业从业人员的整体素质较低,与现代林业生态建设的要求还存在差距,林业教育培训是提高林业在职人员专业技能和知识水平的重要途径。     

我国花生油供求格局及市场走势分析

花生油是中国3大传统植物油中唯一依靠国内自给的油种。国内市场花生油供求目前基本平衡,但花生油的需求将不断增长;随着花生良种补贴和《轻工业调整和振兴规划》等扶持政策的施行,未来中国花生油的供给水平也将进一步提高。预计今后一段时期,花生油价格呈稳中有升态势。     

半仿生法提取细叶小檗总生物碱及抑菌性研究

目的本文通过对细叶小檗果实中生物碱的研究,为细叶小檗的有效合理利用提供参考。方法本实验以细叶小檗总生物碱提取量和抑菌圈直径为考察指标,用10%、20%、30%、40%、50%、60%、70%的乙醇作为溶剂提取细叶小檗中的总生物碱,得出27%乙醇为较好的提取溶剂。以27%乙醇为提取溶剂,进行液料比、温度和超声时间的单因素试验。在单因素试验基础上,采用Plackett-Burman设计、最速上升试验以及中心复合实验响应面设计建立数学模型。结果实验结果表明,最佳提取条件为:乙醇含量27%(V/V)、液料比32mL/g、温度52℃、超声功率800W,提取液的pH值为2.2时,对应提取时间为50min;提取液的pH值为7.6时,对应提取时间为25min;提取液的pH值为8.5时,对应提取时间为25min。在此条件下,细叶小檗中总生物碱的提取量为(16.24±0.54)mg/g,比单一超声波辅助法的提取量提高了1.31倍;抑菌圈直径为(91.21±0.37)mm。结论采用超声波辅助半仿生法比单一采用超声波法对细叶小檗中总生物碱的提取效果更好,提取量提高了1.31倍;抑菌效果提高了1.07倍。相比较国内目前对于小檗属植物小檗碱的平均提取量(16.6±0.6)mg/g相接近,在抑菌活性上有明显提高。