高效液相色谱法快速测定三种果蔬中甲苯氟磺胺和苯氟磺胺残留量

甲苯氟磺胺和苯氟磺胺均为杀菌剂,中等毒性,分解产物可转化为有毒物质,现行国标规定的检测方法为气相色谱-质谱联用法,但操作复杂、仪器普及率不高、适用范围有限。本试验建立了一种高效液相色谱法测定三种果蔬(黄瓜、番茄、葡萄)中甲苯氟磺胺和苯氟磺胺残留量的方法。样品采用QuEChERS方法进行前处理,以乙腈-0.1%甲酸水溶液-乙腈为流动相,梯度洗脱,采用高效液相色谱二极管阵列检测器分析。结果显示,QuEChERS前处理的吸附剂组合为750 mgMgSO4+50 mgC18+250 mgPSA+50 mgGCB,对样品进行净化处理后,上清液澄清,略带色泽,化合物平均回收率在79%以上;甲苯氟磺胺和苯氟磺胺在各自浓度范围内线性关系良好(R2=0.9999),加标回收率为79.73%~97.39%,精密度RSD为1.68%~4.21%(n=6),检出限分别为12.5μg/kg和15.1μg/kg,定量限分别为41.9μg/kg和50.2μg/kg。该方法操作简便、灵敏度高、结果准确可靠,能很好地满足上述三种果蔬中甲苯氟磺胺和苯氟磺胺残留量的分析检测。     

不同生物刺激剂对鲜食玉米产量和品质的影响

为研究生物刺激剂对玉米的增产提质效果,试验探讨不同生物刺激剂对玉米的产量和品质方面的影响,为鲜食玉米的优质高产栽培提供技术支撑。以鲜食玉米‘钱江糯3号’为试验品种,以3种生物刺激剂（阿美滋、美基、保康灵1号）为供试药剂,设置6个处理（阿美滋1000倍液、阿美滋1500倍液、阿美滋2000倍液、美基3000倍液、保康灵1号300倍液、清水对照）,研究大田常规施肥水平下药剂对‘钱江糯3号’的经济性状、产量及品质的影响。在阿美滋1500倍液喷施下,玉米的行粒数、单穗鲜重和单穗净重、产量均最高,蛋白质含量、粗纤维含量、还原糖含量、淀粉含量均居第3位;在保康灵1号300倍液喷施下,玉米的穗粗最高,单穗鲜重、单穗净重、产量均居第2位,蛋白质含量最高,脂肪含量最低,还原糖含量居第2位。阿美滋1500倍液在增加玉米产量上是最佳选择,保康灵1号300倍液则对提升玉米品质最有效果。建议生产上将阿美滋1500倍液与保康灵1号300倍液配合施用,这对鲜食玉米的增产提质效果最好。     

Pharmacokinetics of xylazine after 2-, 4-, and 6-hr durations of continuous rate infusions in horses

Intravenous (i.v.) bolus administration of xylazine (XYL) (0.5 mg/kg) immediately followed by a continuous rate infusion (CRI) of 1 mg kg⁻¹ hr⁻¹ for 2, 4, and 6 hr produced immediate sedation, which lasted throughout the duration of the CRI. Heart rate decreased and blood pressure increased significantly (p > .05) in all horses during the first 15 min of infusion, both returned to and then remained at baseline during the duration of the infusion. Compartmental models were used to investigate the pharmacokinetics of XYL administration. Plasma concentration–time curves following bolus and CRI were best described by a one-compartment model. No differences were found between pharmacokinetic estimates of the CRIs for the fractional elimination rate constant (K_e), half-life (t_1/2e), volume of distribution (V_d), and clearance (Cl). Median and range were 0.42 (0.15–0.97)/hr, 1.68 (0.87–4.52) hr, 5.85 (2.10–19.34) L/kg, and 28.7 (19.6–39.5) ml min⁻¹ kg⁻¹, respectively. Significant differences were seen for area under the curve ( ) (p < .0002) and maximum concentration (C_max) (p < .04). This indicates that with increasing duration of infusion, XYL may not accumulate in a clinically relevant way and hence no adjustments are required in a longer XYL CRI to maintain a constant level of sedation and a rapid recovery.     

关于苗木栽培技术的初步探讨

随着人民群众对生活环境和绿化水平要求的不断提升,苗木行业的市场发展可谓越来越蓬勃,行业前景也是越来越光明。因此与之相关的苗木栽培技术也受到越来越多人的关注。但目前我国苗木行业在栽培技术方面仍存在一定程度的欠缺和不足。基于此,着重对苗木栽培前期的选地、选苗等环节及栽植过程中的技术问题进行分析,希望对今后的工作有所借鉴。     

不同处理对芹菜种子萌发过程中抗氧化系统及激素水平的影响

为研究芹菜种子的萌发机制,采用不同试剂组合（5 g/L NaOH+10% PEG、10% PEG+500 mg/L壳聚糖、5 g/L NaOH+500 mg/L壳聚糖）和不同温度(18、24、30℃)对芹菜种子进行处理,观察芹菜种子的萌发指标,并探究种子萌发过程中的抗氧化系统及内源激素水平的变化。结果表明,30℃对种子发芽率、发芽势及发芽指数提高具有促进作用,加快种子萌发进程。与蒸馏水对照组相比,试剂组合处理在18、24℃时种子发芽率、发芽势和发芽指数升高,促进种子萌发,18℃时5 g/L NaOH+500 mg/L壳聚糖处理下的发芽势最高,24℃时5 g/L NaOH+10% PEG处理下发芽势达到最大值;30℃时不同试剂组合处理间发芽率、发芽势和发芽指数无明显差异。18、30℃对种子具有一定程度的胁迫作用,种子SOD和CAT活性较24℃条件下有所增加;18℃时MDA含量和脯氨酸含量显著增加;5 g/L NaOH+10% PEG处理能显著降低MDA含量。萌发过程中,芹菜种子内部ABA含量下降,GA₃、ZA含量增加。试剂组合及适当高温有利于提高芹菜种子的发芽率、发芽势和发芽指数,促进种子萌发,提高种子萌发整齐度;芹菜种子萌发过程中抗氧化系统和激素水平会积极响应不同的处理条件。     

激光在土地保护、农作物生长及害虫防治领域应用研究进展

由于激光具有功率高、相干性好、光谱线宽窄、光谱范围广等特点,其在土地保护、农作物生长及害虫防治等领域应用广泛.文章综合国内外激光技术在农业领域的应用情况,介绍了已经获得应用的激光诱导击穿光谱仪、激光测距仪、激光雷达系统、激光补光灯等设备在土壤检测、土地平整、激光诱变育种、植物补光和虫害防治等领域发挥的作用,对激光技术对农业领域的推动作用,特别是激光技术在吉林省农业应用方面的情况进行了展望.     

Soil available potassium affected by rice straw incorporation and potassium fertilizer application under a rice–oilseed rape rotation system

Data from 147 field trials were collected to study the influence of straw incorporation on soil potassium (K) under an intensive rice–oilseed rape rotation system, while pot experiments were conducted to evaluate the effects of rice straw incorporation on soil K availability. A significant correlation was observed between the soil available K and the relative yield (RRY) and the relative K uptake (RKU) of oilseed rape, with R² values ranging from 0.07 to 0.08 and from 0.10 to 0.11, respectively, when data were fitted to a logarithmic equation model. In approximately 30% of trials, RRY reached 90%, while soil test available K values were below the critical limit, indicating that soil K values at the time of sampling (within 1 week of rice harvest) underestimated the actual soil K supply capacity. The pot experiment results showed that soil available K was affected by straw incorporation and soil type in the fallow period. The NH₄OAc‐K and NaBPh₄‐K concentrations of soils increased at first, and then, plateaued after 28 days. Straw incorporation significantly influenced the critical soil K concentration, which is important for making accurate K fertilizer recommendation. These results suggested that straw K should be seriously considered in making K fertilizer recommendations. Extending the sampling time from 1 to 3 weeks after the harvesting of rice to stabilize the effects of straw incorporation may help achieve a more accurate evaluation of soil available K.