急性温度胁迫对大口黑鲈存活率及肝脏生化指标的影响

为了探究急性高温胁迫对大口黑鲈(Micropterus salmoides)"优鲈3号"存活率及肝脏生化指标的影响,将25℃(对照组)下暂养的大口黑鲈"优鲈3号"直接放入31、34、37℃水环境中,测定不同温度应激后鱼体的存活率及肝脏生化指标。结果表明:37℃组成活率低于31℃、34℃组,仅为50%。31℃和34℃组T-SOD、GSH-PX、CAT、LZM、AKP和ACP活力在48 h显著高于对照组。37℃组则与对照组无显著差异,且ACP活力在48 h显著低于对照组。结果表明,在培育大口黑鲈"优鲈3号"鱼苗时温度应该保持在34℃以下。     

“一分钟游程”构园法则的适用性研究

“一分钟游程”构园法则将人的视觉感受与园林组景共同考虑,以25~30 m作为组景转换的理想距离,对游路结构进行反复烘托与不断强化,从而形成柔和、丰富的“构景曲线”。选择南北方各具代表性的苏州沧浪亭和北京恭王府花园,分析其园林的景观布局,对比园林空间序列的“起”“承”“转”“合”间距。结果表明,“一分钟游程”构园法则在南方私家园林及北方皇家园林中同样适用,为今后的游线组织与组景布设提供了设计参考。     

农机安全生产“三大”防线探讨

农机的安全生产与农业机械化进程密切相关,关系到人民群众的生命财产安全。构筑农机安全生产"三大"防线是农机安全生产的重要保障。文章对如何落实农机安全生产"三大"防线进行浅要分析。     

滇型杂交粳稻“寻杂29”在水、旱条件下植株性状变化的研究初报

 根据1990～1994年滇型杂交粳稻“寻杂29”水栽和旱种的试验数据和调查资料,从“寻杂29”在水、旱条件下植株性状变化和产量形成的种种差异,论述该品种对不同生态环境的抗逆性和适应能力,初步探索出杂交水稻“寻杂29”旱种的生长发育及其栽培特点,供生产应用参考.     

关于大湘西地区“潇湘”茶公共品牌建设的战略思考

本文在分析研究大湘西地区茶产业现状的基础上,以生态环境、茶树品种、茶叶加工技术及产业经济学等理论为指导,提出大湘西地区建设"潇湘"茶公共品牌的对策建议,助力湘茶千亿产业。     

基于移动互联网的快速“三农”信息交互平台研究

针对农民与“三农”专业人员能及时方便互通的需求,设计以移动互联网的微博、飞信等为载体的快速信息交互平台模型,该平台模型降低了农民信息交流的门槛,只需要手机即可,简捷快速低廉,可在田间地头以信息、拍照的形式咨询专家群的建议.在三农信息建设中具有一定应用价值.     

华杂四号油菜最佳施肥模型及经济效益分析

通过对华杂四号油菜的施氮量、施磷量、施钾量和施硼量的研究 ,找出了对华杂四号油菜产量影响较大的试验因子是 :施氮量、施磷量和施硼量。并利用频数分析法 ,通过计算机模拟寻优 ,建立了华杂四号油菜在淮南稻区 30 0 0kg/ha以上的优化栽培模型     

Growth of Roots Emerged from Excised Phytomers of Three Gramineous Species under a Low Osmotic Potential

Abstract

The growth of crown and lateral roots emerged from the excised phytomers of pearl millet (Pennisetum typhoideum Rich.), barnyard millet (Echinochloa frumentacea Link.) and maize (Zea mays L.) was studied under normal and low osmotic potential conditions. The plants were grown in two solutions with osmotic potentials of –0.02 and –0.54 MPa for 6 days. The relative growth rate of the roots in total length (RGR_L) , was not affected by osmotic stress in pearl and barnyard millets, but that in stressed maize was reduced to 64% of the control. Similarly, the relative growth rate of the roots in dry weight (RGR_W), was not affected by osmotic stress in pearl and barnyard millets, but significantly reduced in maize. Osmotic stress increased the specific root length of the lateral roots in pearl and barnyard millets, but did not affect that of maize. The photosynthetic rate (Pr) in the two millets was decreased to ca. 60% of the control by the stress, and that in maize was reduced to 21%. Under the stress, Pr in the three species was limited mainly by low stomatal conductance, but no clear relationship was found between Pr and osmotic adjustment of the leaf. The relative water content of the leaf was lower in maize than in the two millets. The resistance to water flow through the phytomer (R) was significantly increased by osmotic stress in maize, but not significantly in the two millets. The mean root length (RL) was decreased by the stress in maize, but not in the two millets. The maintenance of RGR_L in the two millets was associated with sustained R, RL and also with the maintenance of Pr and allocation of assimilates to roots.     

TTI交联聚乙烯醇木材胶黏剂的研究

研究在水基中三苯基甲烷-4,4',4"-三异氰酸酯(TTI)交联聚乙烯醇(PVA)所形成的白色乳胶。采用正交试验法探讨聚乙烯醇、催化剂-x、TTI的加入量、反应时间及反应温度对该乳胶性能的影响。合成的单组份环保乳胶适用于木材、纸品等加工业,以及建筑业。     

急性高温胁迫对大口黑鲈"优鲈3号"肝脏凋亡相关酶活性和基因表达的影响

为了探究急性高温胁迫对大口黑鲈“优鲈3号”凋亡相关酶活性和基因表达的影响,将25℃下暂养的大口黑鲈“优鲈3号”直接放入37℃水环境中,探究急性高温胁迫后幼鱼肝脏组织Caspase3、Caspase9和基因酶活的变化。结果显示:37℃高温胁迫后,肝脏Caspase3和Caspase9酶活均显著升高,且随着胁迫时间的延长呈升高趋势,在48 h达到峰值。基因Caspase3和Caspase9的表达量均呈现先升高再下降的趋势,在6 h的表达量达到峰值,随之下降,并在48 h与对照组无显著性差异。BCL-2的表达量于1 h达到峰值,之后显著下降,48 h时BCL-2的表达量仅为对照组的0.04倍。结果表明,高温胁迫会使大口黑鲈“优鲈3号”幼鱼发生凋亡甚至细胞坏死。