Physiological changes in maize plants, submitted to herbicides and pests, should be studied for integrated management in this crop. The objective was to evaluate the chlorophyll a fluorescence in maize genotypes damaged or not by Spodoptera frugiperda, and sprayed with herbicides. The herbicides atrazine and nicosulfuron were applied to the plants at doses of 3 kg ha− 1 and 0.06 kg ha− 1, respectively. A randomized block design in a factorial scheme with an additional treatment 3 (2 × 2 + 1) was used, being the factor A: maize leaves exposed or not to the attack of S. frugiperda; factor B: Herculex® (transgenic maize encoding the Cry1F protein) and Isohybrid (non-transgenic maize) genotypes and an additional treatment represented by the PowerCore® genotype (stacked transgenic maize encoding the Cry1F, Cry1A.105 and Cry2Ab2 proteins). The initial fluorescence of chlorophyll a (F0 - electrons quantum− 1), maximum fluorescence (Fm - electron quantum− 1), ratio between variable fluorescence and maximum fluorescence of chlorophyll a (Fv/Fm) and electron transport rate ETR-µmols electrons m− 2 s− 1) were analyzed. The initial fluorescence of chlorophyll a increased and Fm, Fv/Fm and ETR decreased in plants attacked by the pest. The PowerCore® chlorophyll fluorescence remained in characteristic patterns. Chlorophyll a fluorescence was similar between genotypes with or without herbicides application. Damage by S. frugiperda increased the initial fluorescence of chlorophyll a and reduced the variable fluorescence/maximum fluorescence ratio and electron transport rate, indicating physiological stress in maize plants. The herbicides do not cause physiological stress in plants of maize genotypes with characteristic values of chlorophyll a fluorescence.

中文翻译：

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施用除草剂并受到草地贪夜蛾（鳞翅目：夜蛾科）攻击的转基因玉米中叶绿素 a 的荧光

应对除草剂和害虫影响的玉米植株的生理变化进行研究，以便对该作物进行综合管理。目的是评估被草地贪夜蛾破坏或未喷洒除草剂的玉米基因型中的叶绿素a荧光。除草剂莠去津和烟嘧磺隆分别以 3 kg ha-1 和 0.06 kg ha-1 的剂量施用于植物。使用了额外处理 3 (2 × 2 + 1) 的因子方案中的随机区组设计，作为因子 A：玉米叶是否暴露于 S. frugiperda 的攻击；因子 B：Herculex®（编码 Cry1F 蛋白的转基因玉米）和同种杂交（非转基因玉米）基因型以及以 PowerCore® 基因型（编码 Cry1F、Cry1A.105 和 Cry2Ab2 蛋白的堆叠转基因玉米）为代表的额外处理。叶绿素a的初始荧光（F0-电子量子-1）、最大荧光（Fm-电子量子-1）、可变荧光与叶绿素a最大荧光的比值（Fv/Fm）和电子传输速率ETR-μmols电子m − 2 s− 1) 进行了分析。在被害虫攻击的植物中，叶绿素 a 的初始荧光增加，而 Fm、Fv/Fm 和 ETR 降低。PowerCore® 叶绿素荧光保持特征模式。施用或不施用除草剂的基因型之间的叶绿素a荧光相似。S. frugiperda 的损伤增加了叶绿素 a 的初始荧光，并降低了可变荧光/最大荧光比和电子传递率，表明玉米植株受到生理胁迫。