摘要： 于2005-2006年,在河北省农林科学院粮油作物研究所温室内,用植物光合作用测定法研究了光合作用抑制型除草剂异丙隆防除冬小麦田5种主要杂草的最低致死剂量。试验结果表明,在用药6 d后杂草才表现出明显的药害症状,新叶黄化,生长受抑制;而杂草的光合作用在施药后2 d就明显地受到抑制,药剂处理的杂草叶片的PPM值显著下降,随着用药剂量的增加,杂草的PPM值显著下降。通过测定和统计杂草的鲜质量防效,可以发现,供试的5种杂草对异丙隆的敏感性存在显著差异,播娘蒿(Descurainia sophia)、藜(Chenopodium album)对药剂最敏感,ED90值分别为301.51,286.02 ga.i./hm²;看麦娘较敏感,ED90值为654.83 ga.i./hm²;而荠菜、雀麦不敏感。经回归分析发现,施药后2,4 d杂草的PPM值与用药后14 d的杂草鲜质量防效密切相关,其R2分别为0.968 8,0.942 5。这表明用药后早期的PPM值可以较好地预测除草剂对杂草防效和对冬小麦的安全性。当杂草的PPM值低于20时,异丙隆对杂草的鲜质量防效高于90%;而当PPM值高于40时,药剂对杂草的鲜质量防效低于50%;当小麦的PPM值高于60时,异丙隆对小麦的株高、地上部鲜质量基本无影响。当杂草的PPM值低于20,而冬小麦的PPM值高于60时,异丙隆的剂量即为最低致死剂量。

关键词: 最低致死剂量, 植物光合作用测定仪, 异丙隆, 杂草防治, 小麦安全性

Abstract: The experiment was conducted in the green house in Hebei province in order to determine the Minimum Lethal Herbicide Dosage (MLHD) of photosynthesis inhibit ing herbicide, isoproturon on five weed species and safety to the winter wheat with Plant Photosynthetic Meter (PPM). The results showed that the diagnostics of weed caused by isoproturon which the young leaves turned yellow could be observed after treatment 6d, and the PPM value decreased sharply after treatment 2d. Weed growth was inhibited later on. Both PPM values of weed leaves and weed biomass (shoot fresh weight ) decreased as herbicide dosage increasing. However, the susceptibility of weed species to the isoproturon was different among weed species. Descurainia Sophia and Chenopodium album were very susceptible to the herb-i cide, and ED90 for themwere 301.5 and 286.02 respectively. Alopecurus aequalis was relatively less susceptible to the herbicide which the ED90was 654.83, and Capsella burse pastors and Bromus japonicus were not suscept ible to it. MLHD could be calculated by weed biomass 14 d after applicat ion of the herbicide. There were close relationship between weed biomass reduction rate and PPM values of weed leaves 2- 4d after treatment. This indicated that the PPM value being measured in early days after treatment could give reasonable predict ion on weed control efficacy and on winter wheat safety. The isoproturon usually provided 90% control by weed biomass when PPM value was about 20 and relatively poor efficacy was obtained when PPM value was below 40. The isoproturon usually could not injure wheat by plant height and biomass when PPM value was over 60. The MLHD of isoproturon should be the dosage when PPM value was below 20 measured for weed and over 60 for wheat after treatment 2- 4d.

Key words: MLHD, Plant photosythesis meter, Isoproturon, Weed control, Wheat safety

中图分类号: 

• S451.1