Plants are often exposed to external biotic or abiotic agents that can damage cells. Biotic agents include molecules produced by pathogens, and abiotic agents include ultraviolet radiation, heavy metals and xenobiotic agents such as herbicides. Because of the importance of abiotic stresses and the limited knowledge of the defense responses of plants to stresses, a study was conducted using flow cytometry to evaluate endocellular events in protoplasts of two tomato species, Lycopersicon hirsutum and Lycopersicon esculentum, following exposure to 10 mM CuCl2 and 1% paraquat. During the first 30 min of exposure to 10 mM CuCl2, mean fluorescence intensity values in both species decreased by more than 50% compared to the untreated control. During the first 30 min of paraquat treatment, the production of reactive oxygen species, evaluated as the incidence of protoplasts in which the superoxide anion was present, was 32.9 % and 25.4%, respectively, for L. hirsutum and L. esculentum. Hyperpolarization of the mitochondria for both tomatoes species was observed during the first 2 h. The absence of early membrane damage and the markedly detrimental effects of the treatments on the mitochondria suggest that additional mechanisms which lead to cell death may be involved in these processes, and that these mechanisms may be associated with apoptosis.
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机译：植物通常会接触可能损害细胞的外部生物或非生物制剂。生物制剂包括病原体产生的分子，非生物制剂包括紫外线辐射，重金属和异生物制剂例如除草剂。由于非生物胁迫的重要性以及对植物对胁迫的防御反应的了解有限，因此进行了一项研究，使用流式细胞仪评估了暴露于10 mM CuCl2后两种番茄番茄（番茄）和番茄的原生质体中的细胞内事件。和1％百草枯。与未处理的对照相比，在暴露于10 mM CuCl2的前30分钟内，两种物质的平均荧光强度值降低了50％以上。在百草枯处理的前30分钟内，对于hirsutum和esculentum L. hirsutum和esculentum来说，活性氧的产生量分别为32.9％和25.4％，被评估为存在超氧化物阴离子的原生质体的发生率。在最初的2小时内，两种番茄的线粒体都发生了超极化。没有早期的膜损伤和治疗对线粒体的显着有害作用表明，导致细胞死亡的其他机制可能与这些过程有关，并且这些机制可能与细胞凋亡有关。
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