Phytotoxic and nematicide evaluation of Croton ehrenbergii (Euphorbiaceae)     

María Yolanda Rios  Ismael Len‐Rivera  Ramiro Ríos‐Gomez  Liliana C Crdova‐Albores  Angelica Berenice Aguilar‐Guadarrama 《Pest management science》2019,75(8):2158-2165

  相似文献   

荔枝果皮总RNA提取方法的筛选     

张锐  周开兵 《中国果业信息》2013,42(5)

以三月红荔枝果皮为试验材料，通过采用改良CTAB法、SDS法、改良SDS法、改良Bugos法和RNAplant plus Reagent试剂盒（TIANGEN公司）提取总RNA，采用浓度检测、纯度检测、RT-PCR等方法进行提取结果检测，进而筛选出最佳的提取方法。结果表明，这五种方法都能从三月红荔枝果皮中提取出总RNA，但总RNA浓度和纯度有明显的差异。其中采用改良Bugos法、改良SDS法和RNAplant plus Reagen试剂盒提取RNA的浓度较高；采用改良CTAB法和RNAplant plus Reagen试剂盒提取的总RNA纯度较高，完整性较好。采用SDS法、改良SDS法和改良Bugos法所提取的荔枝果皮总RNA纯度低，降解严重。经RT-PCR验证，采用改良CTAB法和RNAplant plus Reagen试剂盒均能扩增得到200bp的18sRNA编码基因片段。综合以上各项检测的结果，改良CTAB法为提取荔枝果皮总RNA的最佳方法，总RNA质量和得率满足后续分子生物学实验的需要。  相似文献   

Agricultural Policy, Climate Factors and Grain Output： Evidence From Household Survey Data in Rural China     

CHEN Yong-fu  WU Zhi-gang  ZHU Tie-hui  YANG Lei  MAGuo-ying  Chien Hsiao-ping 《中国农业科学(英文版)》2013,(1):169-183

This paper estimates a stochastic frontier function using a panel data set that includes 4 961 farmer households for the period of 2005-2009 to decompose the growth of grain production and the total factor productivity (TFP) growth at the farmer level. The empirical results show that the major contributor to the grain output growth for farmers is input growth and that its average contribution accounts for 60.92% of farmer’s grain production growth in the period of 2006-2009, whereas the average contributions sourced from TFP growth and residuals are only 17.30 and 21.78%, respectively. The growth of intermediate inputs is a top contributor with an average contribution of 44.46%, followed by the planted area (18.16%), investment in fixed assets (1.05%), and labor input (-2.75%), indicating that the contribution from the farmer’s input growth is mainly due to the growth of intermediate inputs and that the decline in labor inputs has become an obstacle for farmers in seeking grain output growth. Among the elements consisting of TFP growth, the contribution of technical progress is the largest (32.04%), followed by grain subsidies (8.55%), the average monthly temperature (4.26%), the average monthly precipitation (-0.88%), the adjusted scale effect (-5.66%), and growth in technical efficiency (-21.01%). In general, the contribution of climate factors and agricultural policy factor are positive and significant.  相似文献   

茶树叶片含水量对抗寒性的影响研究     

李惠民  鹿颜 《茶叶》2013,39(2):72-74

以日照碧波茶业有限公司1#种质资源圃、茶科所试验基地和园区南茶北引基地种植的种质茶树为研究对象，采用阿贝折射仪法测量茶树叶片自由水含量，烘干法测量总含水量，通过计算得到束缚水含量，以此来分析不同茶树的抗寒性。束缚水含量最高的四个植株编号依次为201004111-12、200905112—11、D2—8和49。  相似文献   

Evaluation of Lime Requirement Procedures and Liming Materials for Aquaculture Ponds in Thailand     

《Journal Of Applied Aquaculture》2013,25(3):77-88

Abstract

There were strong correlations between soil pH and pHof water (R² = 0.810) and total alkalinity (R² = 0.724) in laboratory soil-water systems prepared with acidic rainwater and pond soil samples from Thailand. Moreover, water pH and total alkalinity were highly correlated (R² = 0.987). Although soil carbonate concentration was not correlated with total alkalinity, there was a correlation between the product of soil carbonate and soil organic carbon and total alkalinity (R² = 0.482). Other soil properties, exchange acidity, cation exchange capacity, base saturation, and total sulfur, were either not correlated or weakly correlated with total alkalinity. Total alkalinity did not exceed 20 mg/L except in systems with soils containing free carbonate. A method that estimates the amount of liming material needed to completely base-saturate bottom soils and provides an excess of carbonate, should be used in Thailand and other places. Calcitic agricultural limestone gave higher total alkalinity concentration in soil-water systems than dolomitic agricultural limestone. There usually would be no justification for selecting higher-priced dolomitic limestone for use in ponds.  相似文献   

电吸附技术处理高硬度高碱度废水的中试研究   总被引：1，自引：0，他引：1  

孙英战  谢海燕  石文忠  阿力木江·斯拉木  史殿彬  刘丽青 《新疆农业大学学报》2012,35(3):237-241

以乌鲁木齐高新区北区再生水厂的出水作为原水,在不同重碳酸盐碱度(HCO3-)和不同总硬度的进水条件下,研究了电吸附设备对TDS、氯离子、总硬度和HCO3-的去除效果。结果表明,在进水HCO3-浓度为80mg/L,总硬度分别为340,770和1 200mg/L条件下,电吸附设备连续运行6个周期,除HCO3-外,设备对TDS、氯离子、总硬度的去除率较为稳定,当进水HCO3-浓度增加到440mg/L时,4项指标去除率均呈现逐渐下降趋势,且总硬度越高,TDS、氯化物和HCO3-的去除率下降越明显。分析认为电吸附设备在高重碳酸盐碱度进水条件下运行时,HCO3-与钙等硬度离子相互作用,导致电极板结垢,从而影了设备的脱盐效果。  相似文献   

复杂山地森林固定大样地测设方法     

吴天乐  张灿明  牛艳东  陈望  谷志容  曾掌权  肖立新 《湖南林业科技》2013,(4):76-78

简述了森林固定大样地测设基本要求;以南方地形复杂、森林茂密、通视性差的山地为例,从坐标原点确定、建立闭合导线和全站仪放样等方面介绍了复杂山地森林固定大样地闭合导线测设方法。  相似文献   

基于不同方法的汉中盆地稻麦轮作土壤供氮能力评价   总被引：1，自引：0，他引：1  

张方方  马宁博  岳善超  李世清 《中国农业科学》2020,53(19):3996-4009

【目的】比较多种指标评价汉中盆地稻麦轮作土壤供氮能力的可靠性,为当地土壤氮素管理提供参考。【方法】以采集于汉中盆地及周边丘陵区的12个农田耕层土壤为供试土样,以盆栽黑麦草地上部累积吸氮量为参比,以土壤理化性质指标以及矿质氮法、KCl冷凝回流法、酸性高锰酸钾法3种化学方法和淹水培养法、通气培养法2种生物培养方法测定土壤氮素矿化量作为土壤供氮能力指标。【结果】土壤类型是影响土壤供氮能力的重要因素;土壤全氮或有机质可以反映土壤潜在供氮能力;土壤质地、pH、有效磷、CEC、碳酸钙、颗粒组成（砂粒、粉粒、黏粒）均不能反映稻麦轮作土壤供氮能力。矿质氮法测定氮素值与作物吸氮量相关系数为 0.963（P<0.01）,但由于起始矿质氮不能反映有机氮矿化量,故矿质氮法只能反映当前供氮能力,不宜作为土壤供氮能力评价指标;KCl冷凝回流法测得的总矿质氮量与作物吸氮量相关系数为0.912（P<0.01）,而KCl冷凝回流法测得的可矿化氮量与作物吸氮量相关系数为-0.766（P<0.01）,由于KCl冷凝回流法浸取土壤可矿化氮过程中会造成铵态氮的挥发,导致在反映土壤潜在供氮能力和总供氮能力上可能不一致,故KCl冷凝回流法不是反映汉中盆地土壤供氮能力的理想指标;酸性高锰酸钾法测得的总矿质氮量和可矿化氮量与作物吸氮量相关系数分别为0.847和0.833（P<0.01）,既能够反映土壤潜在供氮能力,又能够反映总供氮能力,是最佳化学方法。通气培养条件下,总矿质氮量和可矿化氮与作物吸氮量均不相关,而在淹水培养条件下,总矿质氮量和可矿化氮与作物吸氮量的相关系数分别为0.921和0.890（P<0.01）,表明淹水培养法可以反映汉中盆地稻麦轮作土壤潜在供氮能力和总供氮能力,是良好的生物培养方法。氮素矿化势（N₀）和起始矿质氮+N₀与前4期黑麦草地上部累积吸氮量相关系数分别为0.834和0.845（P<0.01）,与整株累积吸氮量相关系数分别为0.840和0.851（P<0.01）。表明,N₀和起始矿质氮+N₀均可反映土壤潜在供氮能力,但N₀仅能够反映土壤潜在供氮能力,起始矿质氮+N₀可反映土壤潜在供氮能力和总供氮能力,因此,起始矿质氮+N₀是评价汉中盆地稻麦轮作土壤供氮能力的理想指标。【结论】对于汉中盆地稻麦轮作土壤供氮能力的评价,酸性高锰酸钾法是最佳化学方法;淹水培养法是良好的生物培养方法,起始矿质氮+N₀是反映汉中盆地土壤供氮能力的理想指标。  相似文献   

Research Progress of Flavonoids of Medicago sativa on Animal Physiological Activity     

WANG Meng-zhu  LIU Yan-feng  ZHANG Wen-ju 《中国畜牧兽医》2015,42(10):2688-2694

Medicago sativa is one kind of excellent legumes and flavonoids are secondary plant substances which widely distribute in the natural world.This ingredient has bioactivity such as estrogenic effect,antioxidant and cardiovascular system improvement.The article reviewed the flavonoids bioactivity of Medicago sativa on animal and provided reference for further research and development of flavonoids of Medicago sativa.  相似文献   

补饲对湘东黑山羊血液生化指标的影响     

刘鹤翔  欧阳叙向  邓灶福 《家畜生态》2009,(4)

采用32只3~4月龄的湘东黑山羊,研究三种不同补饲水平对其血液生化指标的影响。设1个对照组与3个试验组,试验组平均补饲量依次按100 g/d、200 g/d、300 g/d。结果表明:肥育羔羊的血清尿素氮、钙、无机磷与总蛋白含量在各组间的变化范围依次是:19.77mg/dL~20.98 mg/dL、8.28 mg/dL~10.52 mg/dL、4.14 mg/dL~4.80 mg/dL、72.53 g/L~81.33 g/L。  相似文献