HPLC法测定土壤中莠去津残留量方法的改进

本文对高效液相色谱法（HPLC）测定土壤中莠去津残留量的方法进行了改进，土壤中莠去津的甲醇提取液经净化柱净化后进样，可消除杂质的干扰，使样吕峰基线稳定，峰形完整，检测限为5ng/g，回收率在92%以上。     

Frequency and distribution of herbicide resistance in Raphanus raphanistrum populations randomly collected across the Western Australian wheatbelt

In 2003, a random survey was conducted across the Western Australian wheatbelt to establish the extent and frequency of herbicide resistance in Raphanus raphanistrum populations infesting crop fields. Five hundred cropping fields were visited, with 90 R. raphanistrum populations collected, representative of populations present in crop fields throughout the Western Australian wheatbelt. Collected populations were screened with four herbicides of various modes of action that are commonly used for the control of this weed. The majority of Western Australian R. raphanistrum populations were found to contain plants resistant to the acetolactate synthase (ALS)‐inhibiting herbicide chlorsulfuron (54%) and auxin analogue herbicide, 2,4‐D amine (60%). This survey also determined that over half (58%) of these populations were multiple resistant across at least two of the four herbicide modes of action used in the screening. Only 17% of R. raphanistrum populations have retained their initial status of susceptibility to all four herbicides. The distribution patterns of the herbicide‐resistant populations identified that there were higher frequencies of resistant and developing resistance populations occurring in the intensively cropped northern regions of the wheatbelt. These results clearly indicate that the reliance on herbicidal weed control in cropping systems based on reduced tillage and stubble retention will lead to higher frequencies of herbicide‐resistant weed populations. Therefore, within intensive crop production systems, there is a need to diversify weed management strategies and not rely entirely on too few herbicide control options.     

莠去津在土壤及作物中残留量测定

本文建立了一种土壤和作物中痕量莠去津的高效液相色谱分析方法,比较了超声波提取与振荡提取的回收率,研究了弗罗里硅土净化效果。以甲醇：水（８０／２０,Ｖ／Ｖ）为流动相,检测波长２３５ｎｍ,在ＯＤＳ柱上实现了莠去津与杂质的良好分离。方法简单,分析速度快,测定费用低,检测限为２４ｎｇ／ｇ,回收率为９５％～９７％。     

Investigating the in situ degradation of atrazine in groundwater

This study focused on whether or not atrazine could be degraded by indigenous groundwater bacteria as part of an in situ remediation approach. Groundwater was taken from an unconfined middle upper chalk site where concentrations of atrazine and nitrate were typically in the ranges 0.02-0.2 microg litre-1 and 11.6-25.1 mg NO3-N litre-1 respectively. Sacrificial batch studies were performed using this groundwater spiked with atrazine at a concentration of 10 microg litre-1 in conjunction with a minimal mineral salts liquid (Glu-MMSL) medium which contained glucose as the sole carbon source. Treatments comprised either the Glu-MMSL groundwater cultured bacteria or Pseudomonas sp. strain ADP. Results from sacrificial batches indicated the occurrence of bacterial growth and denitrification as monitored by optical density (absorbance at 600 nm) and NO3-N content. Analysis of atrazine content by solid phase extraction coupled with high-performance liquid chromatography showed no degradation of atrazine over a period of 103 days in either treatment. These results indicated that no acclimatised bacterial community featuring positive degraders to the herbicide atrazine had become established within this chalk aquifer in response to the trace levels encountered.     

阿特拉津降解菌FM326（Arthrobacter sp.）的分离筛选、鉴定和生物学特性

采集除草剂阿特拉津污染的土壤,通过直接涂布法和富集驯化培养分离法,分别获得6株和5株能够降解阿特拉津的细菌。通过降解效率和降解动态试验,筛选到1株高效降解阿特拉津的菌株FM326,该菌株能以阿特拉津为唯一的碳源和氮源生长,培养96h后对1000mg·L-1阿特拉津降解效率达到97%。通过生理生化鉴定和16SrDNA序列分析,菌株FM326鉴定为节杆菌属(Arthrobacter sp.)细菌。该菌株表现出最适生长温度30～35℃,最适生长pH值5～9,好氧生长的生长特性。     

除草剂阿特拉津对血清体系中性激素干扰机理研究

为了进一步了解环境内分泌干扰物对人体内性激素平衡的影响，选择阿特拉津这种已被确认为环境内分泌干扰物的农药，通过研究阿特拉津、天然性激素（雌二醇、睾酮）加入血清后体系紫外吸收峰的变化、温度与体系荧光强度关系等方法，确定了阿特拉津、天然性激素对血清组分的荧光猝灭机理，认为阿特拉津可发生类似天然性激素和血清组分间的基态络合。此外，通过计算各二元体系的结合常数发现，阿特拉津与血清组分的结合常数与天然性激素常数较为接近，可以认为阿特拉津具有与天然性激素相近的对血清组分的结合能力，并可能与天然性激素发生竞争结合，由此影响生物体内正常的性激素水平。     

莠去津高效降解细菌HB-5的固定化研究

以莠去津降解细菌HB-5作为研究对象，探索了降解菌HB-5的固定化方法，并对降解菌HB-5及其固定化菌对土壤中莠去津的降解能力进行了比较。采用注射器滴定方法对细菌HB-5进行了固定化，并对海藻酸钠、聚乙烯醇、卡拉胶、脱乙酰壳多糖4种包埋材料从成本、固定时间等方面进行了比较，筛选出最佳固定条件。研究确定海藻酸钠为最佳包埋剂，并对包埋剂的浓度、包埋粒径等进行了探索，测定了降解菌HB-5及其固定化菌对土壤中莠去津的降解率。结果表明，以浓度为2．5％～3．5％的海藻酸钠溶液作为包埋剂进行固定化，生产的HB-5固定化菌机械强度和物理稳定性好，分离度高，符合实验和应用的要求。菌株经固定化后，降解莠去津的能力大大提高，在第1d以后，其降解率均高于未固定化菌；在第1～7d，随培养时间的延长，降解菌与固定化菌HB-5的降解率迅速提高，在第7d达到85％；在第7～13d，两者的降解率增长缓慢，但在第10d均可达到90％。     

两种除草剂复合污染对蚯蚓的毒性效应

以赤子爱胜蚓为研究对象,采用滤纸急性毒性实验,研究了农药绿麦隆与阿特拉津对蚯蚓的单一和复合毒性效应,2种农药对蚯蚓体内超氧化物歧化酶(SOD酶)活力的影响以及通过苏木素-伊红(HE)染色病理染色切片观察了染毒蚯蚓的细胞形态。单一毒性实验表明,阿特拉津对蚯蚓的毒性大于绿麦隆,绿麦隆和阿特拉津48 h的半致死浓度分别为189.64和43.33 mg.L-1。复合毒性实验表明,绿麦隆分别与30和40 mg.L-1阿特拉津复合,其48 h的半致死量分别为116.03和48.14 mg.L-1。绿麦隆和阿特拉津的复合污染对蚯蚓的毒性具有明显的协同作用,而这种协同作用与污染物的浓度有关。通过观察单一和复合体系中毒蚯蚓SOD酶活力可以看出,无论是单一还是复合体系,随着2种农药浓度的增加,蚯蚓体内SOD酶活性增强。病理HE切片表明,随着绿麦隆浓度的增加,蚯蚓表皮和肠道受损越来越严重,而阿特拉津单体系和绿麦隆与阿特拉津复合体系中毒蚯蚓的消化道破损比较严重,说明绿麦隆和阿特拉津进入蚯蚓体内后作用的部位不同。     

海藻酸钠固定化莠去津降解酶的研究

选取包埋剂海藻酸钠浓度为2.0%、3.0%、3.5%、4.0%,固定剂氯化钙浓度为2.0%、3.0%、4.0%、5.0%以及酶液与海藻酸钠溶液包埋比为50%、20%、10%、5%,设计正交实验,将从细菌HB-5中提取到的莠去津降解酶进行固定化,测定不同配比制成的固定化酶对莠去津的降解特性。结果表明,莠去津降解酶的最佳固定化条件为海藻酸钠浓度为3.0%,酶液与海藻酸钠的包埋比为5%,氯化钙浓度为4.0%。最佳固定化时间为4h,适宜的保存温度为4℃。     

新型油乳剂与莠去津混用时作用机理的研究

本文从药液物理性状测定、电镜观察、植物光合作用和电导率的测定诸方面研究了新型油乳剂与莠去津混用时的作用机理。结果表明,新型油乳剂明显地降低莠去津喷雾液的表面张力和接触角,延长药液的干燥时间,增加药液在杂草叶表面的滞留,并破坏稗草叶表面的蜡质层,提高对莠去津的渗透和吸收,增加杂草叶部外渗液的电导率,加速莠去津对杂草光合作用的抑制,最终导致杂草快速死亡。