Studies on Reducing Nitrogen Excretion: Ⅰ.Net Energy Requirement of Finishing Pigs Maximizing Performance and Carcass Quality Fed Low Crude Protein Diets Supplemented with Crystalline Amino Acids     

Hongyu Chen  Xuewu Yi  Guijie Zhang  Ning Lu  Licui Chu  P. A. Thacker  Shiyan Qiao 《畜牧与生物技术杂志(英文版)》2011,2(2)

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Insecticidal compounds from the essential oil of Chinese medicinal herb Atractylodes chinensis     

Chu SS  Jiang GH  Liu ZL 《Pest management science》2011,67(10):1253-1257

BACKGROUND: In a screening programme for new agrochemicals from Chinese medicinal herbs, the essential oil of Atractylodes chinensis (DC.) Koidz was found to possess strong insecticidal activity against the common vinegar fly, Drosophila melanogaster L. The essential oil was extracted via hydrodistillation, and its constituents were determined by GC‐MS analysis. RESULTS: The main components of A. chinensis essential oil were β‐eudesmol (21.05%), β‐selinene (11.75%), γ‐elemene (7.16%) and isopetasam (5.36%). Bioactivity‐directed chromatographic separation on repeated silica gel columns led to the isolation of five compounds, namely atractylon, α‐elemol, β‐eudesmol, hinesol and β‐selinene. β‐Selinene, α‐elemol and hinesol showed pronounced contact toxicity against D. melanogaster adults, with LD₅₀ values of 0.55, 0.65 and 0.71 µg adult^?1 respectively. Atractylon and β‐eudesmol were also toxic to the fruit flies (LD₅₀ = 1.63 and 2.65 µg adult^?1 respectively), while the crude oil had an LD₅₀ value of 2.44 µg adult^?1. CONCLUSION: The findings suggested that the essential oil of Atractylodes chinensis and its active constituents may be explored as natural potential insecticides. Copyright © 2011 Society of Chemical Industry  相似文献   

电磁感应加热重熔Niwc25粉末涂层与基体结合机理的研究     

储江伟  徐瑞玉 《东北林业大学学报》1991,19(4):61-65

介绍利用高频电磁感应加热重熔NiWC25金属合金粉末涂层与基体结合机理的有关研究结果。采用电子扫描显微镜、波谱分析及能谱分析等手段,证明了涂层与基体具有明显的钎焊特征;金属元素Fe,Ni,W在涂层与基体之间的扩散效应产生了冶金结合,扩散深度可达20—25μm。  相似文献   

氮磷等比与以磷定氮条件下玉米的最大施肥量研究   总被引：4，自引：0，他引：4  

褚清河  潘根兴  李典有  史海平  张旭辉 《土壤学报》2007,44(6):1084-1089

以前的研究已认识到种植玉米的土壤具有平衡与不平衡的土壤养分供应类型,因而其高产施肥需要相应的养分配比。本研究以养分平衡供应的山西石灰性褐土为对象,按照同步增加氮磷用量和以磷定氮等两种施肥量确定方法设置氮磷施肥量,探讨高产玉米的最大施肥量和最佳施肥比例。研究表明,氮磷等比施肥下玉米最大施氮量较以磷定氮增大46 kg hm-2,产量增加738 kg hm-2;而玉米最佳施氮量较以磷定氮增加39 kg hm-2,产量增加723 kg hm-2。氮磷等比施肥下最佳施氮量氮素的增产效益极大。试验说明氮磷施用比例是影响玉米最大施氮量及其肥效的重要因素。在供试的氮磷养分平衡供应条件下同步增加氮磷用量可以得到两者统一的玉米高产最佳施肥量点。本研究提出,根据土壤养分平衡供应特征调整施肥养分比例可能是作物高产施肥且提高肥料利用率的途径。  相似文献   

苏北滨海盐渍土的形成和演化   总被引：2，自引：0，他引：2  

唐淑英  祝寿泉  单光宗  邵希澄  张丽君 《土壤学报》1978,15(2):151-164

为了加速滨海盐渍土的垦殖和改良利用,建设高产稳产的农业生产基地,必须弄清滨海盐渍土的形成演化规律,提高我们认识自然,改造自然的自觉性,减少片面性和盲目性.  相似文献   

Isoflavone profile and biological activity of soy bread   总被引：3，自引：0，他引：3  

Zhang YC  Albrecht D  Bomser J  Schwartz SJ  Vodovotz Y 《Journal of agricultural and food chemistry》2003,51(26):7611-7616

The present study examines the ability of isoflavone extracts from whole soy bread and two soy bread fractions, crumb and crust, to modulate the proliferation of human prostate cancer PC-3 cells. Total isoflavone content in the two fractions of soy bread were similar (3.17 micromol/g dry basis). However, their conjugate patterns were altered. Both fractions of soy bread contained a similar level of isoflavone aglycones ( approximately 24%). Low concentrations of soy bread extracts increased PC-3 cell proliferation as much as 47% compared to untreated control. This proliferative effect in cell growth was reduced at higher extract concentration. Soy bread crust extract (10 mg/mL) reduced PC-3 cell proliferation by 15% compared to untreated control. Interestingly, wheat bread extracts increased cell proliferation at all concentrations tested. Although extracts from both breads possessed biological activity, only soy bread crust extract reduced PC-3 cell proliferation. This observation may be related to the presence of soy in this bread.  相似文献   

滑柱摆臂式悬架车辆之转向梯形断开点的确定          下载免费PDF全文

王志浩  高义民  初亮 《农业工程学报》1995,11(2):70-75

根据机构学原理,将目前农用运输车采用的滑柱摆臂式悬架等效成铰接四杆机构;通过实例计算和断开点主要影响因素分析,提出了正确选择转向梯形断开点位置的新方法。  相似文献   

石灰性土壤钙硼钼配合施用对菜豆生长的影响   总被引：1，自引：0，他引：1  

李春花  杨清 《植物营养与肥料学报》1997,3(1):90-94

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水稻早衰突变体els-R7954的遗传分析和初步定位     

孙出  童杰鹏  王艳  童川  沈圣泉 《核农学报》2015,29(3):421-427

为了深入研究水稻早衰机理,找到有效消除和延缓植株早衰的方法,本研究通过350Gy60Co-γ射线辐照水稻浙恢7954干种子,获得1份特异性水稻早衰突变体。观察该突变体生物学性状,发现苗期生长正常,分蘖末期叶片出现早衰现象,灌浆期整个植株枯黄,早衰现象非常明显,将其暂名为elsR7954(early leaf senescence)。遗传分析和基因定位发现,els-R7954受单隐性核基因控制,位于第2染色体SSR标记RM530和RM3774之间,距RM530约5.0c M。为进一步克隆该基因,丰富叶片早衰的分子机制奠定了一定基础,也为研究水稻早衰,最终提高产量和品质提供可能。  相似文献   

山东省重要农区粉虱寄生蜂调查及初步研究     

李洪冉  张建华  徐丹丹  陶云荔  褚栋 《山东农业科学》2015,(3):88-91,2

为了解山东省田间粉虱寄生蜂情况,于2012年对山东省6市9个地点作物上的粉虱寄生蜂进行了调查,并对其种类及生物学特性进行了初步研究。结果表明:仅在青岛地区(Ch Y4)发现温室白粉虱Trialeurodes vaporariorum(Westwood)被寄生蜂寄生的现象,通过分子鉴定该寄生蜂为丽蚜小蜂Encarsia formosa(Gahan)。进一步研究证明本地区丽蚜小蜂可以寄生烟粉虱(寄生率约23.33%),丽蚜小蜂均被共生菌Wolbachia感染。研究结果对于今后山东省粉虱天敌资源的保护利用等具有指导意义。  相似文献