Glutathione transferase activities toward herbicides used selectively in soybean

Using extracts from suspension-cultured cells of soybean (Glycine max cv. Mandarin) as a source of active enzymes, the activities of glutathione transferases (GSTs) catalysing the conjugation of 1-chloro-2,4-dinitrobenzene (CDNB) and selective herbicides were determined to be in the order CDNB≫ fomesafen>metolachlor=acifluorfen>chlorimuron-ethyl. GST activities showed a thiol dependence in a substrate-specific manner. Thus, GST activities toward acifluorfen and fomesafen were greater when homoglutathione (hGSH), the endogenously occurring thiol in soybean, was used as the co-substrate rather than glutathione (GSH). Compared with GSH, hGSH addition either reduced or had no effect on GST activities toward other substrates. In the absence of enzyme, the rates of hGSH conjugation with acifluorfen, chlorimuron-ethyl and fomesafen were negligible, suggesting that rapid hGSH conjugation in soybean must be catalysed by GSTs. GST activities were subsequently determined in 14-day-old plants of soybean and a number of annual grass and broadleaf weeds. GST activities of the plants were then related to observed sensitivities to post-emergence applications of the four herbicides. When enzyme activity was expressed on a mg^-1 protein basis, all grass weeds and Abutilon theophrasticontained considerably higher GST activity toward CDNB than soybean. With fomesafen as the substrate, GST activities were determined to be in the order soybean≫Echinochloa crus-galli>Digitaria sanguinalis>Sorghum halepense=Setaria faberi with none of the broadleaf weeds showing any activity. This order related well to the observed selectivity of fomesafen, with the exception of A. theophrasti, which was partially tolerant to the herbicide. Using metolachlor as the substrate the order of the GST activities was soybean>A. theophrasti≫S. halepense>Amaranthus retroflexus>Ipomoea hederacea, with the remaining species showing no activity. GST activities toward metolachlor correlated well with the selectivity of the herbicide toward the broadleaf weeds but not toward the grass weeds. Acifluorfen and chlorimuron-ethyl were selectively active on these species, but GST activities toward these herbicides could not be detected in crude extracts from whole plants. © 1997 SCI     

杂草对9类常用不同作用机制除草剂的非靶标抗性机制研究进展

除草剂的应用为农业生产带来便利, 但长期、单一使用某一种或相同机制的除草剂也引发了杂草对除草剂的抗性问题。抗性杂草种类逐渐增加, 抗性形成机制复杂, 导致农田杂草的治理难度增加。杂草对除草剂的抗性机制主要分为两种, 一种是除草剂靶标位点基因的突变或过量表达导致的靶标抗性, 另一种是杂草对除草剂吸收、转运、固存和代谢等一个或多个生理过程发生变化导致的非靶标抗性。本文综述了杂草对9类不同作用方式除草剂的非靶标抗性机制的生理、生化和分子基础的研究进展, 以期为抗性杂草综合治理提供参考。     

准噶尔盆地南部城乡菊科杂草种类与多样性特点

通过近三年的野外实地调查和历年的标本资料,文中对新疆准噶尔盆地南部城乡菊科杂草进行了系统的研究.结果 显示:1)准噶尔盆地南部城乡菊科杂草共有8族43属107种,其中鳢肠、牛膝菊是文中新发现的外来入侵新疆新记录种.2)本区菊科杂草单种属和寡种属共38属71种占主导地位,含4～9种的优势属有蒲公英属、蒿属等11属.3)该...     

黄芩田茎叶处理除草剂筛选试验研究

[研究背景] 黄芩是我国重要中药材,人工种植模式下杂草防除困难,且目前没有登记的专用除草剂。[目的]筛选出适用于黄芩田防除一年生杂草的除草剂品种或组合。[方法]通过调查黄芩田杂草种类、数量,并针对主要杂草,从13种有代表性的茎叶处理除草剂中筛选出对黄芩安全性好的品种进行防效试验,确定除草效果及用量。[结果]60g/L烟嘧磺隆OD 750ml/hm₂^、12%砜嘧磺隆OD 120ml/hm₂^、187.5ml/hm₂^以及10.8%精喹禾灵EW 450ml/hm₂^、675ml/hm₂^、1350ml/hm₂^、108g/L高效氟吡甲禾灵EC 375ml/hm₂^、450ml/hm₂^、900ml/hm₂^{等处理对黄芩安全},鲜重抑制率-1.35%--17.96%;480g/L灭草松AS等其它药剂、处理的黄芩植株全部或多数枯死、植株弱小发黄,对黄芩不安全。12%砜嘧磺隆OD 120ml/hm₂^、187.5ml/hm₂^、240ml/hm₂^、375ml/hm₂^处理药后30天对黄芩田一年生阔叶杂草的总体株防效为84.08%-90.55%,鲜重防效为89.30%-95.38%;对一年生禾本科杂草的总体株防效为54.90%-73.20%,鲜重防效为60.16%-78.52%。10.8%精喹禾灵EW 450ml/hm₂^、675ml/hm₂^{处理对黄芩田一年生禾本科杂草的株防效为}90.20%-95.42%,鲜重防效为93.19%-97.00。108g/L高效氟吡甲禾灵EC 375ml/hm₂^、450ml/hm₂^{处理对黄芩田一年生禾本科杂草的株防效为}95.42%-99.35%,鲜重防效为97.23%-99.54%。[结论]可以使用12%砜嘧磺隆OD 120-187.5ml/hm₂^{防除黄芩田以反枝苋、马齿苋、牛筋草等为主的一年生杂草},对黄芩安全。禾本科杂草群体较大时,加入10.8%精喹禾灵EW 450-675ml/hm₂^或108g/L高效氟吡甲禾灵EC 375-450ml/hm₂^,以增加对禾本科杂草的防效。     

玉米田养鹅对土壤理化性状、杂草多样性及玉米生长的影响

为探究"玉米田养鹅"对农田生态系统杂草多样性、土壤理化性质及玉米生长状况的影响,以林芝市八一镇章麦村试验田为研究对象,运用对比方法,研究玉米田养鹅(Raising geese in cornfield,RGC)和对照(Control,CK)土壤理化性质、杂草多样性及玉米生长的异同,旨在通过田间状态的描述和中间状态的研究,为以后优化玉米田调控措施提供依据。结果表明:1)RGC处理有19种杂草,其中以菊科植物最多,对照组仅有9种。不同功能群杂草密度相差很大,双子叶一年生或越年生被子植物功能群杂草密度远远高于其他5种功能群;RGC处理提高了杂草群落Shannon-Wiener和Simpson多样性指数,但降低了Pielou均匀度指数和Margalef物种丰富度指数;2)RGC处理土壤含水率较对照高1.27%,与对照相比差异不显著(P0.05);3)随着土层加深,RGC和对照土壤紧实度均呈逐渐增加趋势,且RGC对紧实度影响显著;4)对照土壤碱解氮含量为86.48mg/kg,略高于RGC处理2.67mg/kg(P0.05),速效钾含量为161.07mg/kg,略高于RGC处理28.66mg/kg(P0.05),而RGC的土壤中速效磷含量为120.98mg/kg,是对照(106.25mg/kg)的1.14倍(P0.05)。结论:RGC处理增加了农田系统杂草数量、种类和生物量,提高了生物多样性,使土壤紧实度明显减小、土壤含水率增加及土壤养分含量出现差异,且玉米各项农艺性状低于对照。     

江苏省镇江市麦田杂草发生情况调查

为了摸清江苏省镇江市麦田杂草种类、分布状况、出草规律、草相变化、防除情况等,通过倒"W"形九点取样法对镇江市麦田杂草进行了调查。调查结果显示镇江市麦田杂草有29科99种,日本看麦娘、菵草、猪殃殃、看麦娘、稻槎菜、硬草、繁缕、大巢菜、荠菜、涩荠、野老鹳草、牛繁缕、早熟禾为该地区主要危害性杂草,其中菵草、日本看麦娘、猪殃殃为麦田杂草群落优势种。不同地形区域杂草种类和优势种不同。镇江市麦田杂草由20世纪90年代初以看麦娘、日本看麦娘和猪殃殃等为主演变为以菵草、日本看麦娘、猪殃殃为主,稻槎菜、硬草、繁缕等发生较重。出草高峰集中在小麦播后15 d左右,具体到镇江来说11月底至12月上旬为杂草发生高峰期。针对镇江本地杂草发生情况,制定了以土壤封闭和茎叶处理相结合的防控技术方案。     

甘肃河西地区口岸外来杂草的调查与监测

通过实地杂草疫情监测,对甘肃河西地区口岸入侵杂草的种类、原产地、生活型、引入途径、入侵性等方面进行了调查分析。调查发现口岸地区常见杂草29科107种,菊科、豆科、禾本科、藜科杂草为4个优势科;其中88种为外来入侵杂草,主要集中在菊科和禾本科,原产地亚洲和欧洲为主,主要的入侵方式为无意引入。尚未发现检疫性入侵杂草分布。另外针对加强检疫监管及进境粮谷及矿砂携带杂草撒漏扩散提出几点建议。