Intoxication of Mesotrione in Corn Inoculated with Azospirillum brasilense and with Application of Plant Growth Regulators

ABSTRACT: The objective of this study was to evaluate the effect of intoxication by mesotrione herbicide on the initial development and yield of maize after seed inoculation or foliar spray application with Azospirillum brasilense and application of plant regulators. Therefore, three experiments were performed: one under greenhouse conditions and two under field conditions, in different locations. In all experiments, a randomized block design was used with a 2 x 4 factorial arrangement, representing presence (192 g ha-1) or absence of mesotrione and four treatments corresponding to the control; seed inoculation with A. brasilense; foliar spray application of A. brasilense; foliar spay application of auxin + gibberellin + cytokine (AX + GA + CK), and foliar spay applications with mesotrione were carried out at the V3 stage of the crop. The results from the greenhouse experiment, with mesotrione application, were intoxication of 7.12%, which reduced total chlorophyll content by 10.15% and carotenoid content by 75.86%, leading to reductions in gas exchange and chlorophyll a fluorescence, and increased activity of antioxidative enzymes. Under field conditions, the treatments did not reduce the effects of intoxication during the initial development of maize crop and did not increase crop yield. It was concluded that the use of A. brasilense and plant regulators did not protect maize against mesotrione intoxication in the initial development, nor did it increase yield.

摘要：本研究旨在评估硝磺草酮（mesotrione）除草剂药害对经巴西固氮螺菌（Azospirillum brasilense）种子接种或叶面喷施，以及施用植物生长调节剂后的玉米初始生长与产量的影响。为此，共开展3组试验：1组设于温室环境，2组设于不同地点的大田环境。所有试验均采用随机区组设计，设置2×4因子排列：其一为硝磺草酮施用与否（施用量为192 g ha⁻¹），其二为4种处理，分别为空白对照、巴西固氮螺菌种子接种处理、巴西固氮螺菌叶面喷施处理、生长素+赤霉素+细胞分裂素（AX + GA + CK）叶面喷施处理；此外于玉米V3生长期喷施硝磺草酮。温室施用硝磺草酮的试验结果显示，玉米药害率达7.12%，总叶绿素含量降低10.15%，类胡萝卜素含量降低75.86%，进而抑制气体交换与叶绿素a荧光参数，并提升抗氧化酶活性。大田环境下，各处理未能缓解玉米初始生长阶段的药害效应，亦未提升作物产量。综上，施用巴西固氮螺菌与植物生长调节剂，既无法在玉米初始生长阶段抵御硝磺草酮药害，亦未对作物产量产生提升效果。