沉水植物在养殖池塘中的生态效应

在水体交换量较低、养殖密度较高的池塘中，养殖对象的活动会引起水中植物营养元素、氨氮等有害物质和有机物的积累，底质也因残饵和鱼体排泄物的堆积，耗氧量增加，导致整个水体的水质恶化，并对养殖对象的生长产生抑制。因此，如     

Estimating Combining Ability of 4x-2x Crosses in Cultivated Potatoes

Progenies derived from crosses between Solarium tuberosum and 2n pollen-Producing diploid hybrids, exhibit obvious hybrid vigor. The 2n pollen-producing clone can act as a bridge in crossing S. tuberosum and S. andigena with S. phureja. Populations from 4x-2x crosses show more unifomity and less segregation compared with that of 4x-4x crosses. The parent-offspring correlation for the traits, starch content and tuber number, is significant at 0.01 level. The regrssion equations are Y (mp-F1)=1.0 1.2x and Y (mp - F1) = 5.3 0.8x, respectively. The 2n pollen-producing clones play an impotant role in increasing tuber stach content. Estimates of the combining ability for the main yield components indicate that additive effect prodominatcs for such trais as plot yield, tuber weight per plant and starch content, whereas both additive and non-additive effects lay equal stress on mean tuber weight and non-additive effect is important for tuber number. In general, non-additive effect appears to be important in     

冷藏和气调处理对青花菜 Glucoraphanin 含量的影响

Glucoraphanin (4-甲基亚磺酰丁基芥子油苷 )在青花菜中含量丰富 ,其降解产物Sulforaphane具很强的抗癌活性。本试验以‘Marathon’青花菜为试材 ,将新鲜花球切成小花球后用 10 0mg/L的NaClO表面消毒 1min ,清水洗净。分别取 6 5 0g花球置于 0℃、 5℃和 10℃冷藏 ,并在 5℃下进行 5种气调处理 :1)Air,2 )Air+10 %CO2 ,3)Air+2 0 %CO2 ,4) 1%O2 ,5 ) 1%O2 +10 %CO2 。每一处理分别在处理当天、处理后 3、 6、 9、 12d取样 5 0g ,真空冷冻干燥 ,并研磨成粉末状贮藏于 4℃待用。将 0 .2g冷冻干燥样品在沸水中煮 10min ,35 0 0g离心 5m…     

硫酸铜对泥鳅精子活力的影响

以泥鳅精子为受试材料,应用计算机辅助精子分析系统,研究硫酸铜(0.1、1、10 mg/L)对泥鳅的精子活力的影响.结果表明,在0 h试验组,0.1 mg/L的硫酸铜明显降低泥鳅精子运动速度,1 mg/L的硫酸铜对运动时间和速度产生显著抑制作用,10 mg/L的硫酸铜时运动百分数、运动时间和速度都产生明显影响(P<0.0...     

种养结合家庭农场发展策略

本文主要总结了种养结合家庭农场的发展策略,要获得长期持续发展,需要在防疫卫生制度和环境卫生控制长效管理、日常生产和农产品质量、环保措施和环保意识、杜绝转包代养顽疾以及提高家庭农场发展活力和"造血"能力等方面加以提高和改进。     

基于ArcGIS的煤矿塌陷土地损毁程度分析

土地损毁程度分析是土地复垦适宜性评价、复垦方向确定、复垦工程措施制定的重要前提。煤矿开采造成的损毁土地具有位置集中、涉及地类多、面积大等特点,因此,正确合理的土地损毁程度分析对于提高复垦质量具有重要意义。通过对土地复垦方案编制实例的研究表明,研究者利用Arc GIS软件可以准确高效的获取煤矿塌陷损毁土地的损毁程度情况,为土地复垦后续工作的开展提供有力保障。     

新形势下农机安全监理工作思考

昭阳区农业和农村发展已进人一个优化结构、提高质量、注重效益的新阶段。如何理清工作思路，探索农机监理行为准则，保证农机化事业健康发展，促进农业增效和农民增收，是我们每一个农机监理人需要认真思考的问题。     

Comparison of two doses of recombinant human bone morphogenetic protein in absorbable collagen sponges for bone healing in dogs

OBJECTIVE: To determine the effects of 2 doses of recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge (rhBMP-2/ACS) on bone healing in dogs. ANIMALS: 27 adult dogs. PROCEDURES: Dogs underwent a mid-diaphyseal (1-mm) tibial osteotomy (stabilized with external skeletal fixation) and received an ACS containing 0.28 mg (0.2 mg/mL) or 0.56 mg (0.4 mg/mL) of rhBMP-2 or no treatment (control dogs). All dogs were examined daily; bone healing was assessed via radiography and subjective lameness evaluation every 2 weeks. After euthanasia at 8 weeks, tibiae were evaluated biomechanically and histologically. RESULTS: Control dogs required antimicrobial treatment for pin-site-related complications more frequently than did rhBMP-2/ACS-treated dogs. At 4 and 6 weeks, weight bearing was greater in dogs treated with rhBMP-2/ACS (0.2 mg/mL) than in control dogs, albeit not significantly. Compared with control treatment, both doses of rhBMP-2/ACS accelerated osteotomy healing at 4, 6, and 8 weeks, and the 0.2 mg/mL dose enhanced healing at 2 weeks; healing at 6 weeks was greater for the lower-dose treatment than for the higher-dose treatment. Histologically, healing at 8 weeks was significantly improved for both rhBMP-2/ACS treatments, compared with control treatment. Among groups, biomechanical variables did not differ, although less osteotomy-site failures occurred in rhBMP-2/ACS-treated groups. CONCLUSIONS AND CLINICAL RELEVANCE: In dogs that underwent tibial osteotomy, rhBMP-2/ACS (0.2 mg/mL) appeared to accelerate bone healing and reduce lameness (compared with control treatment) and apparently augmented bone healing more than rhBMP-2/ACS (0.4 mg/mL). Compared with control dogs, rhBMP-2/ACS-treated dogs required antimicrobial treatments less frequently.