一种进行磺酰脲类和三嘧啶磺酰胺类除草制剂测试与残留研究的生物测定法

本文探索出一种用豌豆和狭叶羽扇豆的根对磺酰脲类（绿磺隆、ｔｒｉａｓｕｌｆｕｒｏｎ和甲磺隆）与三唑嘧啶磺酰胺类除草剂进行常规评估的生物测定方法。对ｐＨ值从５．８至８．４,质地从砂土至粘土的土壤进行了试验。两种植物对绿磺隆和ｆｌｕｍｅｔｓｕｌａｍ的灵敏度相似,它们对不同除草剂和不同土壤类型的反应范围分别为：０．７５￣６．０ｎｇ ｔｒｉａｓｕｌｆｕｒｏｎ／ｇ土壤（Ｗｉｍｍｅｒａ灰粘土）,０．１２５￣８．     

单嘧磺隆在土壤中的残留分析和消解动态研究

研究了新磺酰脲除草剂单嘧磺隆在土壤中的残留分析方法及其土壤消解动态和最终残留。土壤经甲醇和稀氨水混合液提取 ,液液分配及 C18净化 ,浓缩后用带紫外检测器的高效液相色谱仪进行测定。单嘧磺隆的最低检出量为 4 ng,在土壤中的最低检出浓度为0 .0 2 mg/ kg。本方法的添加回收率为 95.10 %～ 10 3.77% ,变异系数为 1.4 7%～ 11.80 % ,符合农药残留分析的要求。运用上述方法 ,测定了单嘧磺隆在北京和山东土壤中的消解动态以及最终残留。结果表明 :单嘧磺隆在土壤中消解的速度较慢 ,在北京土壤中的半衰期为 9.2 4 d,山东土壤中的半衰期为 13.59d。按推荐剂量施药 ,小麦收获时 ,在北京和山东两地土壤中均未检出单嘧磺隆。     

噻吩磺隆的残留分析及其在玉米田的残留规律研究

建立了噻吩磺隆在土壤、玉米和玉米植株中的超声提取、固相萃取净化和高效液相色谱-质谱联用 残留检测方法,测定了在田间施药条件下噻吩磺隆在土壤中的消解动态及其在土壤、玉米和玉米植株中的最终残留。土壤、玉米和玉米植株样品经乙腈-磷酸盐缓冲溶液(pH 7.8)浸泡、涡旋并超声提取后,经固相萃取柱净化,用反相高效液相色谱-质谱检测。结果表明,噻吩磺隆在该方 法下的最小检出量为0.2 ng,在10倍浓缩倍数条件下的最低检出浓度为2 μg/kg,定量限为6 μg/kg,平均添加 回收率为77.9% ~100.4%,变异系数在1.6% ~6.5%之间。田间试验结果表明:噻吩磺隆在土壤中的半衰期分别为0.92~1.23 d;按推荐剂量施药,距施药时间40 d后和玉米收获时,在土壤、玉米和玉米植株中均未检出噻吩磺隆。     

大豆田土壤中氯嘧磺隆残留动态研究

采用高效液相色谱法对大豆田土壤中的氯嘧磺隆残留动态进行了研究。结果表明,氯嘧磺隆在大豆田土壤中的降解半衰期为7～10d,施药后60d其残留量为0．004mg／kg。     

降解菌2N3对被氯嘧磺隆污染土壤的生物修复

在实验室条件下,研究了高效降解菌2N3(克雷伯氏菌属,Klebsiella sp.)对被氯嘧磺隆污染土壤的修复作用及其影响因素。当土壤中氯嘧磺隆的添加浓度为20 mg/kg,每 1克土壤中2N3的接菌量为1×106个菌体时,第30 d时土壤中氯嘧磺隆的降解率为84.6%,对照仅为13.4%;相同2N3接菌浓度下,当土壤中氯嘧磺隆浓度为100 mg/kg时,其降解率为31.1%。以小麦、玉米、黄瓜为供试作物,在土壤中施加 20 mg/kg的氯嘧磺隆, 当每 1克土壤中2N3的接菌量为1×106个 菌体时,小麦、玉米、黄瓜的出苗率分别为85%,82%和79%,且处理组株高高于对照,表明降解菌2N3具有明显减轻氯嘧磺隆药害的作用。研究表明,人工接种降解菌2N3可提高土壤中氯嘧磺隆的降解率,有效降低其在土壤中的残留。     

毛细管电泳定量测定稻田土壤中痕量磺酰脲类除草剂残留

研究了提取浓缩和毛细管电泳相结合测定稻田土壤中低剂量多个磺酰脲类除草剂混合残留的分析方法。结果表明: 毛细管电泳可有效分离和定量测定稻田土壤中甲磺隆、氯磺隆和氯嘧磺隆混合残留。通过定量补偿甲磺隆、氯磺隆和氯嘧磺隆可使残留检测限达到ng/kg级,回收率>87%。表明毛细管电泳具有定量测定土壤中ng/kg级磺酰脲类除草剂残留的能力。     

土壤中砜嘧磺隆和氯磺隆残留的光化学荧光分析方法研究

用紫外线照射非荧光特性的砜嘧磺隆和氯磺隆,通过生成具有荧光特性的衍生物,分别研究了其在不同介质中的荧光特性及其影响因子,建立了测定土壤中砜嘧磺隆和氯磺隆残留的光化学荧光分析法(PCF)。结果表明:在2×10-3 mol/L、一定酸碱度(砜嘧磺隆pH 7、氯磺隆pH 12)的十六烷基三甲基氯化铵(CTAC)胶体分散体系中,紫外照射150 s是PCF法测定砜嘧磺 隆和氯磺隆残留的最佳条件,在此条件下砜嘧磺隆和氯磺隆的检出限(LOD)分别为0.7和0.6 μg/kg, 相对标准偏差(RSD)分别为1.7%和2.1%;在黄松田水稻土、黄红壤性水稻土和青紫泥田水稻土3种不同性质的土壤中,砜嘧磺隆和氯磺隆同时测定的平均回收率分别为99.0%±1.0%和98.7%±4.1%、97.6%±1.7%和97.0%±4.7%、96.7 %±2.3%和95.4%±5.5%;所建立的PCF法可有效、快速测定土壤中同时残留的微量砜嘧磺隆和氯磺隆。     

甲磺隆结合态残留物对土壤微生物的影响

研究了不同处理土壤中结合态甲磺隆残留物对土壤微生物群落的影响。结果表明,在供试浓度下,土壤中甲磺隆结合态残留物的生态效应仍不容忽视,其对土壤细菌、真菌具有显著的刺激作用,而对土壤放线菌却有强烈的抑制作用,抑制率高达100%,至培养结束时(84 d)放线菌数量还未恢复到对照水平。但微生物反应程度在不同土壤、氮素水平及培养时间上皆存在一定的差异性。土壤微生物群落,尤其是放线菌可作为评价甲磺隆除草剂残留污染土壤生态环境效应的敏感指标。外源氮素(尿素)的添加,既能增加土壤微生物的数量,也能缓减结合态农药残留物对土壤放线菌的毒害效应。     

蔺草田杂草安全高效防除技术研究(一)

绿磺隆对蔺草生长有一定的抑制作用,近年来随着杂草草相的变化,防效也下降。用农思它、果尔、速收等除草剂替代绿磺隆,对杂草有较好的防除效果,也未发现土壤残留和作物药害。     

甲磺隆污染土壤生物修复的初步探索

以14C-甲磺隆为例,通过投加优选菌株青霉(Penicillium sp.)和发酵有机肥,研究了污染土壤中甲磺隆除草剂的生物修复。结果显示,加入优选菌株Penicillium sp.或有机肥对甲磺隆污染土壤进行生物修复是可行的,Penicillium sp.或有机肥的引入,显著提高了土壤中甲磺隆残留物的降解速率,并大大减少了土壤中结合态甲磺隆残留物的形成,甲磺隆的降解半衰期由162.3 d降至42.5~51.6 d,56 d时其结合残留率仅为1.1%~4.6%,而对照土壤中结合残留率仍达到35.6%。     

Fate of [14C]diflubenzuron on cotton and in soil

Aqueous suspensions and oil emulsions of a commercial [¹⁴C]diflubenzuron (N-[[(4-chlorophenyl)amino]carbonyl]-2,6-difluorobenzamide) formulation (Dimilin W-25) remained on the leaf surface of greenhouse-treated plant tissues. Absorption, translocation, and metabolism of the [¹⁴C]diflubenzuron were not significant. Less than 0.05% of the applied ¹⁴C was found in newly developed plant tissues 28 days after spray treatment. [¹⁴C]Diflubenzuron was degraded in soil. After 91 days, biometer flask studies showed that 28% of the ¹⁴C incorporated into the soil as [¹⁴C]diflubenzuron was recovered as ¹⁴CO₂. Major dichloromethane-soluble soil residues were identified as unreacted [¹⁴C]diflubenzuron and [¹⁴C]4-chlorophenylurea. A minor unknown degradation product cochromatographed with 2,6-difluorobenzoic acid. Insoluble ¹⁴C-residues increased with time and represented 67.8% of the residual ¹⁴C in the soil 89 days after treatment. Cotton plants grown for 89 days in [¹⁴C]diflubenzuron-treated soil contained only 3% of the ¹⁴C applied to the soil. Small quantities of acetonitrile-soluble [¹⁴C]4-chlorophenylurea were isolated from the foliar tissues. Root tissues contained small amounts of [¹⁴C]diflubenzuron and trace quantities of a minor ¹⁴C-product that chromotographed similarly to 2,6-difluorobenzoic acid. Most of the ¹⁴C in the plant tissues (84–93%) was associated with an insoluble residue fraction 89 days after treatment.     

Enterohepatic circulation and biliary secretion of 5,6-dihydro-5,6-dihydroxy[14C]carbaryl glucuronide in the rat

Intestinal absorption (enterohepatic circulation) and biliary secretion of ¹⁴C from a metabolite of carbaryl isolated from rat bile, 5,6-dihydro-5,6-dihydroxy[¹⁴C]carbaryl glucuronide, and its aglycone were observed: Lincomycin and kanamycin sulfate were also given to rats to determine the effect of an altered intestinal microflora on the above processes. Net absorption of ¹⁴C from the glucuronide occurred in the small intestine and cecum of control rats (68.5%); 10% of the infused ¹⁴C was secreted in the bile. Antibiotic treatment affected the site of absorption and the biliary secretion of ¹⁴C from the glucuronide since net ¹⁴C absorption occurred only in the small intestine of antibiotic-treated rats (32.5%) and biliary secretion accounted for less than 1% of the infused ¹⁴C. The site of absorption of ¹⁴C from the aglycone and biliary secretion of ¹⁴C (17%, control rats; 14%, antibiotic-treated rats) were not affected by antibiotic treatment. Carbon-14 from the aglycone was absorbed primarily in the small intestine (89.3%, control rats; 84.2%, antibiotic-treated rats). The results indicate that the intestinal microflora influence the enterohepatic circulation and biliary secretion of the glucuronic acid conjugate of 5,6-dihydro-5,6-dihydroxycarbaryl.     

Animal metabolism of propham (isopropyl carbanilate): The fate of residues in alfalfa when consumed by the rat and sheep

Alfalfa was root-treated with [¹⁴C]propham (isopropyl carbanilate[¹⁴C-phenyl(U)]) for 7 days and then harvested and freeze-dried. Rats and sheep were orally given either ¹⁴C-labeled alfalfa roots ([¹⁴C]root) or ¹⁴C-labeled alfalfa shoots ([¹⁴C]shoot). When the [¹⁴C]root was given, 6.5–11.0% of the ¹⁴C was excreted in the urine and 84.6–89.4% was excreted in the feces within 96 h after treatment. Less than 3% of the ¹⁴C remained in the carcass (total body—gastrointestinal tract and contents) 96 h after treatment. When [¹⁴C]shoot was given, 53.2–55.2% of the ¹⁴C was excreted in the urine, 32.1–43.4% was excreted in the feces, and the carcass contained 0.2–1.1% of the ¹⁴C 96 h after treatment. When the insoluble fraction (not extracted by a mixture of CHCl₃, CH₃OH, and H₂O) of both alfalfa roots and shoots was fed to rats, more than 86% of the ¹⁴C was excreted in the feces and less than 3% remained in the carcass 96 h after treatment. The major radiolabeled metabolites in the urine of the sheep fed ¹⁴C shoot were purified by chromatography and identified as the sulfate ester and the glucuronic acid conjugates of isopropyl 4-hydroxycarbanilate. Metabolites in the urine of the sheep treated with [¹⁴C]root were tentatively identified as conjugated forms of isopropyl 4-hydroxycarbanilate, isopropyl 2-hydroxycarbanilate, and 4-hydroxyaniline. The combined urine of rats dosed with [¹⁴C]shoot and [¹⁴C]root contained metabolites tentatively identified as conjugated forms of isopropyl 4-hydroxycarbanilate, isopropyl 2-hydroxycarbanilate, and 4-hydroxyaniline.     

Absorption and efflux of chloro-s-triazines by Setaria roots*

The absorption and loss of four chloro-s-triazines was investigated in excised roots of four Setaria taxa. Different taxa absorbed the various triazines at different rates. In general, triazine absorption was greater at 2°C than at 22.5°C, and absorption rates were linear functions of external concentrations. Efflux studies showed marked differences in the rate of loss of ¹⁴C-atrazine, ¹⁴C-simazine, and ¹⁴C-propazine from root sections of robust white foxtail (Setaria viridis var. robustaalba Schreiber). The roots lost ¹⁴C-atrazine very quickly, and the loss was similar in either water or ¹²C-atrazine. Atrazine appears to be restricted to the apoplast of the root. ¹⁴C-atrazine was lost more rapidly than either ¹⁴C-simazine or ¹⁴C-propazine to water or to solutions containing the unlabelled herbicide. Efflux of ¹⁴C-simazine was greater than that of ¹⁴C-propazine to solutions of CaCl₂. From the pattern of efflux, it was concluded that ¹⁴C-simazine and ¹⁴C-propazine accumulated in the root symplast. Furthermore, the decreases in chloro-s-triazine absorption in the presence of metabolic inhibitors (dinitrophenol, sodium arsenite) may suggest that ¹⁴C-simazine and ¹⁴C-propazine entered the symplast by an energy-dependent process.     

干旱和复水对两种葡萄砧木叶片光合和叶绿素荧光特性的影响

采用盆栽称重控水法,干旱胁迫处理1103P和101-14M两种砧木,处理21 d后复水,分别测定干旱处理0、7、14、21 d及复水第7、14 天,葡萄砧木叶片光合和叶绿素荧光参数。结果显示：干旱胁迫后,1103P和101-14M的净光合速率(Pn)均逐渐降低,101-14M的Pn降幅大于1103P,短时间干旱胁迫引起两种砧木Pn降低的主要因素是气孔限制,而长时间干旱胁迫后Pn降低主要是非气孔限制。随着干旱胁迫的持续,1103P和101-14M的初始荧光产量(Fo)呈增加趋势,但101-14M的增幅大于1103P,说明干旱胁迫后101-14M的光反应中心受损害程度大于1103P;复水后1103P和101-14M两种砧木的Pn值逐渐增加,复水第7天,二者分别为对照的83.20%和66.31%,复水第14天,分别为对照的107.30%和88.43%; 复水后1103P和101-14M两种砧木的Fo值呈现逐渐降低趋势,复水后第7天,1103P和101-14M 的Fo值为对照的102.95%和109.60%,复水后第14天,1103P和101-14M Fo为对照的101.56%和101.81%,说明复水后1103P和101-14M两种砧木受损的光合反应中心得到了修复,光合速率也逐渐恢复,1103P复水后恢复生长的能力高于101-14M。     

Effects of triazole inhibitors of sterol biosynthesis on the free and esterified sterol composition of celery cell suspension cultures

Treatment of celery cell suspension cultures with paclobutrazol and three other triazoles resulted in decreased growth and an accumulation of 14α-methylsterols in both the free sterol and the steryl ester pools, thus indicating that the triazoles were inhibiting the action of the plant obtusifoliol 14α-demethylase system. Obtusifoliol, 14α-methylcampesta-8,24(24¹)-dien-3β-ol and 14α-methylcampest-8-en-3β-ol were the main 14α-methylsterols to increase in the free sterol pool. In the presence of the triazoles the steryl esters became virtually depleted of sitosterol, campesterol, stigmasterol and isofucosterol, which were replaced by 14α-methylsterols with obtusifoliol becoming the dominant esterified sterol. Treatment of the celery culture with a fourth triazole which did not have a noticeable effect on growth and caused negligible accumulation of 14α-methylsterols in the free sterol pool nevertheless produced some enrichment of the steryl esters in obtusifoliol. The results indicate that, following triazole treatment, a rapid esterification of the accumulating 14α-methylsterol intermediates occurs before they start to build up in significant amount in the free sterol pool.     

水稻干尖线虫14-3-3(Ab-14-3-3-a)基因克隆与功能分析

水稻干尖线虫是水稻上重要的寄生线虫,严重危害水稻安全生产。14-3-3蛋白调控生物体的细胞代谢、生长发育和逆境适应等一系列生物过程。本研究通过c DNA末端快速扩增技术(rapid amplification of c DNA ends,RACE)分离获得了一个水稻干尖线虫(Aphelenchoides besseyi)14-3-3基因,命名为Ab-14-3-3-a。Ab-14-3-3-a全长c DNA序列含有59 bp的5'非翻译区(UTR)、编码251个氨基酸756 bp的开放阅读框。Ab-14-3-3-a DNA序列包含4个外显子和3个内含子。Ab-14-3-3-a蛋白与其他植物寄生线虫14-3-3蛋白氨基酸序列高度相似,系统发育树显示与植物寄生线虫位于同一进化分支。原位杂交显示Ab-14-3-3-a特异定位于成虫的背食道腺细胞中,表明其在线虫取食和寄生过程中发挥潜在功能。qRT-PCR显示,Ab-14-3-3-a在水稻干尖线虫各个龄期均表达,其中在成虫表达水平最高,而在发育过程中幼虫表达水平最低。当线虫取食不同寄主时,Ab-14-3-3-a的表达水平具有差异性,线虫取食感病水稻早期,Ab-14-3-3-a表达水平上升1.5倍,而取食灰葡萄孢(Botrytis cinerea)时Ab-14-3-3-a表达可提高数百倍。利用体外RNA干扰技术将Ab-14-3-3-a的表达进行有效抑制,结果显著影响了线虫的产卵、成虫发育以及线虫种群数量。综上,Ab-14-3-3-a参与调控水稻干尖线虫的取食行为和发育进程。本研究相关结果有助于拓展植物寄生线虫14-3-3蛋白功能,为深入研究线虫与植物互作机制提供了理论依据。     

A study of ethylene and CO2 evolution from ethephon in tobacco

Buffers and leaf discs of mature tobacco (Nicotiana tabacum L.) were utilized to study [¹⁴C]-ethylene and ¹⁴CO₂ evolution from radiolabeled ethephon, (2-chloroethyl)phosphonic acid. Metabolic fate of [¹⁴C]ethephon in leaf discs was investigated by use of thin-layer chromatography, high-voltage paper electrophoresis, autoradiography, and liquid scintillation spectroscopy. The evolution of labeled ethylene generally increased with increasing buffer pH, buffer volume, and dosage of [¹⁴C]ethephon. [¹⁴C]Ethylene was evolved, increasingly with time, from [¹⁴C]ethephon either added to the buffer or applied to leaf discs. The rate of [¹⁴C]ethylene evolution was maximum during the first day and leveled off on the fourth day. More than 50% of the total [¹⁴C]ethylene evolution over a 96-hr period was recovered during the first 24 hr after [¹⁴C]ethephon application. No ¹⁴CO₂ was evolved when [¹⁴C]ethephon was degraded in the presence of buffer or leaf discs. Only ethephon itself, and no detectable metabolite thereof, was discovered in the methanolic extract of the leaf disc tissue. An insignificant amount of ¹⁴C activity (approximately 2% of the extracted ¹⁴C) was detected in the residue. By means of gas chromatography, it was confirmed that in buffers and tobacco leaf tissue ethephon breaks down to release ethylene but not CO₂.     

淡紫拟青霉对大豆胞囊线虫卵及2龄幼虫的影响

研究了淡紫拟青霉M-14、IPC菌株对大豆胞囊线虫卵孵化及2龄幼虫活性的影响。结果表明,M-14滤液及其菌丝内溶物、IPC滤液、ZnCl_2溶液等不同处理间存在极显著差异(P<0.01)。代谢产物对卵生理活性的影响因试验菌株的不同而异,M-14菌株发酵滤液及其内容物对大豆胞囊线虫卵的孵化具有强烈的抑制作用,而IPC菌株的影响则较弱。大豆胞囊线虫2龄幼虫在M-14发酵滤液原液及1倍稀释液中均表现为麻痹僵直,线虫死亡率随时间的延长而增加,72h后幼虫死亡率分别达到96.8％和90.5％。将经M-14原液处理24h的幼虫置于清水中,仅有极少数能够恢复活性,证明M-14代谢产物具有很强的杀线虫活性。     

锦鸡儿等旱生树种抗旱生理的研究

研究了青海东部干旱半干旱地区常见的１４种旱生树种在多项抗旱生理指标上的特征。通过凋萎系数的测定将参试树种的抗旱程度进行了初步划分。深入研究了多项水分生理指标，并据此进行了主成份二维排序，将参试树种按耐旱特征划分为五个不同的抗旱类型，供各种生态类型区选用。又综合多指标对１４个树种的抗旱顺序进行了综合排序。