施肥对农田土壤碳氮磷化学计量特征及相关酶活变化的影响

归纳不同施肥条件下土壤养分和微生物量碳氮磷(CNP)化学计量特征及与之相关的酶活性变化,从施肥制度与土壤中养分平衡的关系着手制定出更加合理的施肥措施.通过数据整合分析,收集已公开发表施肥土壤中CNP化学计量比和酶活性变化的相关中、英文文献,提取有效数据,然后进行数据分析,通过绘制森林图明确土壤和微生物量CNP化学计量特...     

Dichlorodiphenyltrichloroethane determination in air by thermal desorption gas chromatography-mass spectrometry

BACKGROUND: Current quantitative methods for airborne dichlorodiphenyltrichloroethane (DDT) require collection and extraction times of ≥ 12 h. The aim of this study was to develop a method for quantifying airborne DDT with a short (<4 h) collection and analysis time. RESULTS: Precision [relative standard deviation (RSD)] for each calibration point (0.8–9.0), linearity (R² = 0.99) and apparent recovery (R′ = 96.5%) were determined from thermal desorption (TD) gas chromatography–mass spectrometry (GC-MS) analyses of Tenax-TA-packed sampling tubes spiked with 1–250 ng of DDT. Recovery of ¹³C-labeled 4,4′-DDT from tubes spiked before and after air sampling was 97.3 and 90.3% respectively. DDT was detected and quantified in 1–3 L samples of air collected during 10–180 min sampling events. A significant difference was observed in DDT air concentration between 28 and 33 °C during microchamber studies. CONCLUSIONS: The results demonstrate that the TD GC-MS method developed in this study is precise, reproducible and linear over the span of 1–250 ng of DDT spiked onto TD tubes. By avoiding dilution of the sample, the method described allows the measurement of DDT vapor concentrations during short sampling periods (10–180 min) relevant to mosquito behavior studies. Published 2012 by John Wiley & Sons, Ltd.     

In what way dose bordeaux spray kill the potato leafhopper?

American Journal of Potato Research -     

口蹄疫灭活疫苗的免疫效果及其对鉴别诊断的干扰

灭活疫苗免疫是防控口蹄疫的重要措施,但是灭活疫苗的免疫效果及其对感染与免疫鉴别诊断的干扰一直是口蹄疫免疫无疫区建设评估需要明确的重要问题。本研究中选择了3个企业（代号A、B与C）的4组口蹄疫O型与A型二价灭活疫苗,分别免疫口蹄疫抗体阴性健康未成年牛,免疫3～4次,测定免疫前后结构蛋白和非结构蛋白抗体的应答水平。结果显示：（1）结构蛋白抗体合格率：a1组（A企业多批次疫苗）4次免疫后O型和A型均为100%;a2组（A企业同批次疫苗）一~三免O型为36.7%、98.3%与100%,A型为15%、86.7%与100%;b组（B企业疫苗）一~三免O型为18.3%、97%与100%,A型为1.7%、45%与53.3%;c组（C企业疫苗）一~三免O型为26.7%、96.7%与100%,A型为21.7%、71.7%与100%。（2）非结构蛋白3ABC抗体阳性率（两种方法复核结果）：a1组一~四免分别为0.7%、1.4%、9.5%与4.8%;a2组和c组三次免疫均未检测到阳性;b组仅三免后阳性率为0.6%。3组灭活疫苗首次免疫牛的抗体合格率远不及70%,但加强免疫后抗体合格率均显著提高;非结构蛋白抗体检测结果表明有3组疫苗的抗原纯净度符合OIE的要求,但a1组灭活疫苗免疫后,仍然对感染与免疫鉴别诊断存在干扰;采用两种非结构蛋白抗体检测方法进行复核检验,可以提高感染与免疫鉴别诊断的准确性。本研究为口蹄疫免疫无疫评价方案的制定提供了科学依据。     

鸭绿江细鳞鱼溯河产卵的生态学观察

作者通过对鸭绿江吉林省长白县江段进行调查,报导了鸭绿江细鳞Brachymystax lenok P.)亲鱼溯河产卵的生物学特性与环境生态特点。     

亚香棒虫草的研究

亚香棒虫草（ＣｏｒｄｙｃｅｐｓｈａｗｋｅｓｉＧｒａｙ）是霍克斯拟青霉（Ｐａｅｃｉｌｏｍｙｃｅｓｈａｗｋｅｓｉ）寄生于宿主昆虫湖南棒蝠蛾（Ｎａｐｉａｌｕｓｈｕｎａｎｅｎｓｉｓ）而形成的一种虫草，它的化学成份与冬虫夏草（Ｃ．ｓｉｎｅｓｉｓ）相似，且具一定的药用价值。本文综述了近年来湖南棒蝠蛾的生物学特性、生态学；霍克斯拟青霉菌的生物学特性及其分离培养技术；虫草的分布、生境、形成；化学成份及其药理等方面的研究进展     

桑蓟马为害对桑叶和蚕茧的影响

研究了桑蓟马为害对桑叶产量和营养物质及蚕茧产量的影响。通过虫日指数与各因子的回归分析表明，桑蓟马的累积为害使桑叶重量降低，含水量减少，营养状况恶化，总糖、蛋白质和氨基酸总量等均随虫日指数增加而下降。以不同受害水平桑叶饲育的家蚕，各处理间三四龄幼虫的生长发育及蚕病发生率无明显差异，但随着虫日指数的增加，家蚕发育历期延长，蚕茧产量呈对数函数下降。     

日粮核苷酸对早期断奶小鼠肝脏基因表达的影响

研究了日粮核苷酸对早期断奶小鼠肝脏基因表达的影响:选取16～17日龄健康BALB/C雄性小鼠60只,分成对照组和实验组,分别饲喂添加0、0.25%核苷酸的无核苷酸基础日粮,在实验的第2、4、10天采用差异显示技术分离小鼠肝脏中差异表达的基因。结果表明:采用6对引物分离到4条差异表达的基因片断。采用差异显示技术初步分离到4个受核苷酸影响差异表达的基因,这些片段需要做进一步的验证。     

Effects of ferrous sulfate with sulfuric acid on tea (Camellia sinensis (L.) O. Kuntz) soil environment

In brown tea soil, the effects of ferrous sulfate with sulfuric acid on soil environment and tea plant (Camellia sinensis (L.) O. Kuntz) growth were examined by enzyme activity, microbe quantity, nutrients in rhizosphere soil, and the nutrients and dry matter weight in the tea plant. We found that the pH value in the brown soil was significantly decreased by ferrous sulfate with sulfuric acid treatments, compared with the value in unfertilized control (CK) or sulfuric acid treatments. The acid phosphatase activities of 3 g kg^–1 ferrous sulfate with 0.05 mL L^–1 sulfuric acid were increased by 210.53%. Interestingly, the quantities of fungi were increased by 19.76% and the bacteria and actinomyces were decreased in the CK treatment. Specifically, the nitrogen and magnesium in rhizosphere soil and leaves were significantly increased by the low concentrations of ferrous sulfate with 0.05 mL L^–1 sulfuric acid, whereas the dry matter weight under 3 g kg^–1 ferrous sulfate with 0.05 mL L^–1 sulfuric acid was increased by 36.22% in the CK treatment. Thus, we concluded that ferrous sulfate with sulfuric acid affected not only the soil environment but also the growth of tea plants. Our results suggested that the concentration of ferrous sulfate at 3 g kg^–1 soil diluted in 0.05 mL L^–1 sulfuric acid could be considered a good soil conditioner to make a suitable soil environment for tea production.