回归设计应用于大豆化学除草配方最佳剂量的筛选初探

本文对Ｄ－饱合设计法应用于大豆田化学除草剂混配最佳剂量的筛选进行了初步探索，并建立了拉索、丁草胺、广灭灵三种药剂用量与除草效果、杂草鲜重的数学模型，经Ｘ２与相关检验，模型的拟合度极好，具有推广价值。应用微机进行仿真模拟，获得了此三种除草剂混配应用于大豆田除草的最佳剂量为：（拉索８７．７－１２８．７ｍＬ＋丁草胺１０８．７～１３８．８ｍＬ＋广灭灵５０．１～６３．１ｍＬ）／６６７ｍ２。     

植物性样品中甲草胺残留的测定方法

对大蒜、辣椒等植源性食品的甲草胺残留进行检测,确定了甲草胺的气相色谱测定方法。甲草胺添加水平为0.01～0.10mg/kg,线性关系良好,进行6次分析,其精密度符合要求。经反复测定发现该方法简单、快捷,有效地解决了植源性食品样品中的甲草胺残留测定的问题。     

Biodegradation of aged residues of atrazine and alachlor in a mix-load site soil

A selected microbial consortium (SMC) capable of degrading two specific herbicides, alachlor (2-chloro-2′,6′-diethyl-N-[methoxymethyl]-acetanilide; AL) and atrazine (2-chloro-4-ethylamino-6-isopropylamino-S-triazine; AT) was isolated from a pesticide-contaminated mix-load site soil. Evaluation of bioaugmentation as a feasible bioremediation strategy for this mix-load site soil (Site 5A) was initiated in standard laboratory biometer flasks utilizing the isolated SMC. The biometer flasks were monitored for CO₂ evolution and pesticide degradation. The total amount of CO₂ evolved from the treated biometer flasks was significantly different from the control flasks. The rate of CO₂ evolution was 2.6 times faster in the treated soil (0.0123 mM CO₂ d⁻¹ vs. 0.0048 mM CO₂ d⁻¹). The total net CO₂ produced in the treated biometer flasks was 0.9481 mM, representing mineralization of approximately 10% of the AT and AL initially present. Forty-eight percent of AT and 70% of AL was degraded in the inoculated biometer flasks. The first-order rate constants were 0.0064 d⁻¹ and 0.1331 d⁻¹ for AT and AL, respectively. The calculated half-life of AT was 108 d while a 50% decrease in AL occurred by Day 5. In just 2 d, 20% of the AT was degraded while only 10% of the AL disappeared. The initial fast degradation rate of AT was followed by a much slower, more gradual degradation rate period that lasted about 35 d. Alternatively, the rate of AL degradation increased after the second day resulting in 60% of the AL being transformed by the end of the first week. Alachlor degradation appeared to be dependent upon AT degradation especially during the first several days of the incubation period. Complete disappearance of the herbicides over the study time was not achieved.     

Isolation of a selected microbial consortium from a pesticide-contaminated mix-load site soil capable of degrading the herbicides atrazine and alachlor

Contaminated soil from a 100-year-old mix-load site located in Reading, PA was evaluated for its potential to provide indigenous microorganisms capable of degrading two widely utilized herbicides, atrazine (2-chloro-4-ethylamino-6-isopropylamino-S-triazine; AT) and alachlor (2-chloro-2′,6′-diethyl-N-[methoxymethyl]-acetanilide; AL). Three different locations from the site were chosen for experimentation based on herbicide handling activities. Standard enrichment techniques were used to isolate a selective microbial consortium (SCM) with the desirable degrading capabilities. Three enrichment treatment schemes were evaluated; AT and AL, AL alone, and only AT. Degradative organisms were isolated from only one of the sample locations. Considerable differences in the soil parameters of the three sample locations were found that might have had an effect on the ability of the indigenous microbial populations within the soil to degrade AT and AL. In the initial cultures from this location, degradation occurred in the AT and AL treatment only. Because the AT and AL were the only sources of carbon and nitrogen (N) for the microbes, these results suggest that AL alone was not a sufficient N source. In general, the ability to degrade AL by the SMC was dependent on AT degradation. Alachlor degradation did not begin until approximately 15% of the AT was transformed. Once all of the AT was removed very little further AL degradation occurred. The average half-life (t_1/2) of AT was 7.5 d, while average t_1/2 for AL degradation was 11 d. Individual colonies from the SMC were identified by fatty acids methyl ester (FAME) analysis. Five strains were identified with similarity indexes above 70%. These isolates included the following: Alcaligenes xylosoxydans subsp. denitrificans, Alcaligenes xylosoxydans subsp. xylosoxydans, Pseudomonas putida, Pseudomonas marginalis, and Providencia rustigianii.     

几种化肥对水溶液中甲草胺光解的影响

以高压汞灯为光源 ,研究了几种常用化肥对水溶液中甲草胺光解的影响。研究结果显示 ,当单独用 1种化肥作为甲草胺光解影响因子时 ,硝酸钾对甲草胺的光解具有较明显的光敏化作用 ,照光 9min时的光猝灭率为 2 9.5 9% ;磷酸二氢钙则表现出光猝灭作用 ,照光 9min时的光猝灭率达 85 .11% ;碳酸氢铵、硝酸铵、尿素对甲草胺的光解影响不显著