Laboratório de Fisiologia de Plantas sob Estresse, Universidade Federal do Paraná, Setor de Ciências Biológicas, Departamento de Botânica, Avenida Coronel Francisco H. dos Santos, 100, Caixa Postal 19031, Centro Politécnico, 81531-980, Curitiba, Paraná, Brazil.
Universidade Federal de Minas Gerais, Instituto de Ciências Biológicas, Departamento de Botânica, Avenida Antônio Carlos, 6627, Pampulha, Caixa Postal 486, 31270-970, Belo Horizonte, Minas Gerais, Brazil; Universidade Federal de Lavras, Departamento de Biologia, Campus UFLA, Caixa Postal 3037, 37200-000, Lavras, Minas Gerais, Brazil.
Chemosphere. 2019 Oct;233:905-912. doi: 10.1016/j.chemosphere.2019.06.032. Epub 2019 Jun 5.
We investigated the interconnected roles of reactive oxygen species (ROS) generated upon seed exposure to glyphosate and/or gibberellic acid (GA), and the possible interaction between the herbicide and the plant hormone during germination of sorghum seeds. GA decreased antioxidant enzyme activity in embryos, and the over accumulation of hydrogen peroxide (HO) in 1000 mM GA-treated seeds resulted in the lowest germinability among treatments. The deleterious effects of glyphosate on germination rate, in contrast, were not related to HO accumulation, but to its interference with the mitochondrial electron transport chain. However, interactions among glyphosate, GA and HO during seed germination were observed. Similar to paclobutrazol, glyphosate appears to interfere with the de novo synthesis of gibberellin, which modulates seed germination through oxidative metabolism. Seeds experiencing increased oxidative status due to GA (100 mM) or HO (50 mM) applications had the effects of glyphosate on germination rate reversed. Since decreased ATP synthesis is a secondary effect of glyphosate, increased HO concentrations in embryos must facilitate germination by decreasing the energy required by ATP-demanding metabolism. Our results showed that glyphosate affect seed germination of sorghum, and that the herbicide interacts with oxidative and gibberellin metabolisms.
我们研究了种子暴露于草甘膦和/或赤霉素（GA）时产生的活性氧（ROS）的相互关联作用，以及在高粱种子发芽过程中，除草剂和植物激素之间可能存在的相互作用。GA 降低了胚中的抗氧化酶活性，而在 1000mM GA 处理的种子中，过氧化氢（HO）的过度积累导致处理中发芽率最低。相比之下，草甘膦对发芽率的有害影响与 HO 积累无关，而是与其对线粒体电子传递链的干扰有关。然而，在种子发芽过程中观察到草甘膦、GA 和 HO 之间的相互作用。与多效唑类似，草甘膦似乎干扰了赤霉素的从头合成，赤霉素通过氧化代谢来调节种子发芽。由于 GA（100mM）或 HO（50mM）的应用导致氧化状态增加的种子，其发芽率受到草甘膦的影响发生逆转。由于 ATP 合成的减少是草甘膦的次要作用，因此胚胎中 HO 浓度的增加必须通过降低对 ATP 需求代谢所需的能量来促进发芽。我们的研究结果表明，草甘膦影响高粱种子的发芽，并且该除草剂与氧化和赤霉素代谢相互作用。
