Morphological and Metabolic Changes in Soybean Plants Cultivated in Irrigated Rice Rotation and as Affected by Imazapyr and Imazapic Herbicides Carryover

ABSTRACT: The appearance of soybean cultivars that are tolerant to herbicides from the imidazolinone group enables irrigated rice rotation conducted on Clearfield® system. The objective of this work was to evaluate the morphological and metabolic changes of soybean cultivars containing Cultivance® (CV), which is tolerant to imidazolinone, sulphonylurea toletant (STS) and Roundup Ready® (RR), which is tolerant to glyphosate as affected by carryover of increasing doses of imazapyr and imazapic herbicides mixture, applied in the management of irrigated rice crop. Thus, experiments were conducted on the field and in greenhouse, evaluating phytotoxicity, height, leaf area, shoot dry matter, as well as variables related to the secondary metabolism of plants like chlorophyll, carotenoids, hydrogen peroxide, lipid peroxidation and electrolytes leakage. Soybean cultivars RR and STS are susceptibles to the carryover of imazapyr and imazapic mixture applied in the management of irrigated rice crop, whereas the CV cultivar is resistant. The rise in the herbicide carryover dose increases the reactive oxygen species (ROS) production in soybean plants. The RR cultivar, in general, shows higher ROS production compared to the other soybean cultivars.

摘要：耐咪唑啉酮类（imidazolinone）除草剂的大豆品种面世后，基于Clearfield®系统的灌溉水稻轮作模式得以实现。本研究旨在评估：在递增剂量甲氧咪草烟（imazapyr）与甲咪唑烟酸（imazapic）混剂残留（该混剂曾用于灌溉水稻田的杂草管理）影响下，三类大豆品种的形态与代谢变化。供试品种包括耐咪唑啉酮类的Cultivance®（CV）品种、耐磺酰脲类（sulphonylurea）的STS品种，以及耐草甘膦的Roundup Ready®（RR）品种。本研究通过田间与温室试验，测定了植株的药害程度、株高、叶面积、地上部干物质积累量，并分析了与植物次生代谢相关的多项生理指标，包括叶绿素含量、类胡萝卜素含量、过氧化氢含量、脂质过氧化程度以及电解质渗漏率。试验结果表明：RR与STS型大豆品种对灌溉水稻田管理中施用的甲氧咪草烟与甲咪唑烟酸混剂残留具有敏感性，而CV品种则表现出抗性。除草剂残留剂量的升高会增加大豆植株内活性氧（ROS）的生成量。总体而言，RR型大豆品种的活性氧生成量高于其余两类供试大豆品种。