Arntzen C J, Ditto C L, Brewer P E
U.S Department of Agriculture/SEA, University of Illinois, Urbana, Illinois 61801.
Proc Natl Acad Sci U S A. 1979 Jan;76(1):278-82. doi: 10.1073/pnas.76.1.278.
The effectiveness of diuron, atrazine, procyazine, and cyanazine were compared in controlling growth of redroot pigweed (Amaranthus retroflexus L.) in hydroponic culture. A very marked differential inhibition response was observed for atrazine between resistant and susceptible biotypes. Procyazine and cyanazine exhibited less dramatic differential responses, whereas diuron was equally effective in controlling growth in both biotypes. Photosystem II activity of chloroplasts from both triazine-resistant and triazine-susceptible biotypes was inhibited by diuron but only the chloroplasts from triazine-susceptible biotypes were inhibited significantly by atrazine. The photochemical activity of chloroplasts from triazine-resistant biotypes was partially resistant to procyazine or cyanazine inhibition. The parallel lack of diuron differential effects, partial procyazine and cyanazine differential response, and very marked atrazine differential response in both whole plant and chloroplast assays indicates that the chloroplast is the site of selective herbicide tolerance in these triazine-resistant redroot pigweed biotypes.Photosystem II photochemical properties were characterized by analysis of chlorophyll fluorescence transients in the presence or absence of herbicides. Data with susceptible chloroplasts indicated that both diuron and atrazine inhibit electron flow very near the primary electron acceptor of photosystem II. Only diuron altered the fluorescence transient in resistant chloroplasts. In untreated preparations there were marked differences in the fast phases of the fluorescence increase in resistant vs. susceptible chloroplasts; these data are interpreted as showing that the resistant plastids have an alteration in the rate of reoxidation of the primary photosystem II electron acceptor. Electrophoretic analysis of chloroplast membrane proteins of the two biotypes showed small changes in the electrophoretic mobilities of two polypeptide species. The data provide evidence for the following herbicide resistance mechanism: genetically controlled modification of the herbicide target site.
在水培条件下，比较了敌草隆、莠去津、扑灭津和氰草津对反枝苋（Amaranthus retroflexus L.）生长的控制效果。观察到莠去津在抗性和敏感生物型之间有非常明显的差异抑制反应。扑灭津和氰草津表现出的差异反应不太显著，而敌草隆对两种生物型的生长控制效果相同。敌草隆抑制了抗三嗪和敏感生物型叶绿体的光系统II活性，但只有敏感生物型的叶绿体被莠去津显著抑制。抗三嗪生物型叶绿体的光化学活性部分抵抗扑灭津或氰草津的抑制。在全株和叶绿体试验中，敌草隆缺乏差异效应、扑灭津和氰草津有部分差异反应以及莠去津有非常明显的差异反应，这表明叶绿体是这些抗三嗪反枝苋生物型中选择性除草剂耐受性的位点。通过分析有无除草剂存在时的叶绿素荧光瞬变来表征光系统II的光化学特性。敏感叶绿体的数据表明，敌草隆和莠去津都在光系统II的初级电子受体附近抑制电子流动。只有敌草隆改变了抗性叶绿体中的荧光瞬变。在未处理的制剂中，抗性和敏感叶绿体荧光增加的快速阶段存在明显差异；这些数据被解释为表明抗性质体中光系统II初级电子受体的再氧化速率发生了改变。对两种生物型叶绿体膜蛋白的电泳分析表明，两种多肽的电泳迁移率有微小变化。这些数据为以下除草剂抗性机制提供了证据：除草剂靶位点的基因控制修饰。
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