Farnese Fernanda S, Oliveira Juraci A, Paiva Elder A S, Menezes-Silva Paulo E, da Silva Adinan A, Campos Fernanda V, Ribeiro Cléberson
Laboratório de Ecofisiologia Vegetal, Instituto Federal GoianoRio Verde, Brazil.
Departamento de Biologia Geral, Universidade Federal de ViçosaViçosa, Brazil.
Front Plant Sci. 2017 Apr 19;8:516. doi: 10.3389/fpls.2017.00516. eCollection 2017.
High arsenic (As) concentrations are toxic to all the living organisms and the cellular response to this metalloid requires the involvement of cell signaling agents, such as nitric oxide (NO). The As toxicity and NO signaling were analyzed in leaves. Plants were exposed to four treatments, for 24 h: control; SNP [sodium nitroprusside (NO donor); 0.1 mg L]; As (1.5 mg L) and As + SNP (1.5 and 0.1 mg L, respectively). The absorption of As increased the concentration of reactive oxygen species and triggered changes in the primary metabolism of the plants. While photosynthesis and photorespiration showed sharp decrease, the respiration process increased, probably due to chemical similarity between arsenate and phosphate, which compromised the energy status of the cell. These harmful effects were reflected in the cellular structure of , leading to the disruption of the cells and a possible programmed cell death. The damages were attenuated by NO, which was able to integrate central plant physiological processes, with increases in non-photochemical quenching and respiration rates, while the photorespiration level decreased. The increase in respiratory rates was essential to achieve cellular homeostasis by the generation of carbon skeletons and metabolic energy to support processes involved in responses to stress, as well to maintaining the structure of organelles and prevent cell death. Overall, our results provide an integrated view of plant metabolism in response to As, focusing on the central role of NO as a signaling agent able to change the whole plant physiology.
高浓度砷（As）对所有生物均具有毒性，而细胞对这种类金属的反应需要细胞信号传导因子的参与，如一氧化氮（NO）。对叶片中的砷毒性和NO信号传导进行了分析。将植物进行四种处理，持续24小时：对照；SNP [硝普钠（NO供体）；0.1 mg/L]；As（1.5 mg/L）和As + SNP（分别为1.5和0.1 mg/L）。砷的吸收增加了活性氧的浓度，并引发了植物初级代谢的变化。虽然光合作用和光呼吸急剧下降，但呼吸过程增加，这可能是由于砷酸盐和磷酸盐之间的化学相似性，从而损害了细胞的能量状态。这些有害影响反映在叶片的细胞结构中，导致细胞破裂并可能引发程序性细胞死亡。NO减轻了这些损害，它能够整合植物的核心生理过程，使非光化学猝灭和呼吸速率增加，而光呼吸水平下降。呼吸速率的增加对于通过生成碳骨架和代谢能量来实现细胞稳态至关重要，以支持参与应激反应的过程，以及维持细胞器的结构并防止细胞死亡。总体而言，我们的结果提供了植物对砷反应的代谢综合视图，重点关注NO作为能够改变整个植物生理的信号传导因子的核心作用。
