Plants primed by humic acids showed physiological and molecular response against different abiotic stresses without the presence of stressor agents (salinity, drought, heavy metal toxicity). It is plausible that humic acids themselves can act as chemical priming substances in plants. We hypothesized that humic acids can trigger the weak acids stress response in cell plants acidifying the cytosol and thus eliciting the transduction signalling response cascade. The dose–response curves of maize seedlings roots with different concentrations of humic, acetic and salicylic acids determined the most active and inhibitory concentration. These data were further used to evaluate changes on intracellular pH using BCECF-AM probe (2,7-bis(2-carboxyethyl)-5(and 6)-carboxyfluorescein, acetoxymethyl ester) and differential transcription level of genes related to weak stress response in plants by qPCR real time. Humic acids like short chain organic acids decrease the intracellular pH showed by the increased fluorescence of BCECF probe. The drop in cytosolic pH promoted by humic acids was not transient. We observed a high level of protein kinases related to cell energy-sensing and transcription factors associated to transduction of stress signalling. The humic acids can be considered as a chemical priming agent, since in the appropriate concentration they can induce the typical plant abiotic stress response of weak acids inducing plant acclimation and enhancing the abiotic stress tolerance.

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腐殖酸引发玉米幼苗弱酸胁迫响应

腐植酸引发的植物在不存在胁迫因子的情况下（盐度，干旱，重金属毒性）对不同的非生物胁迫表现出生理和分子响应。腐殖酸本身可以作为植物中的化学引发物质是合理的。我们假设腐殖酸可以在细胞植酸中触发弱酸胁迫反应，从而使细胞质酸化，从而引发转导信号反应级联反应。腐殖酸，乙酸和水杨酸浓度不同的玉米幼苗根部的剂量反应曲线决定了最活跃和最抑制的浓度。这些数据进一步用于通过BCECF-AM探针（2,7-双（2-羧乙基）-5（和6）-羧基荧光素，qPCR实时检测植物弱胁迫反应相关基因的差异转录水平。腐殖酸如短链有机酸会降低BCECF探针荧光显示的细胞内pH。腐殖酸促进的胞质pH下降不是暂时的。我们观察到高水平的蛋白激酶，与细胞压力感应和转录信号转导相关的转录因子有关。腐殖酸可以被认为是一种化学引发剂，因为在适当的浓度下，它们可以诱导弱酸的典型植物非生物胁迫响应，从而诱导植物适应环境并增强非生物胁迫耐受性。腐殖酸如短链有机酸会降低BCECF探针荧光显示的细胞内pH。腐殖酸促进的胞质pH下降不是暂时的。我们观察到高水平的蛋白激酶，与细胞压力感应和转录信号转导相关的转录因子有关。腐殖酸可以被认为是一种化学引发剂，因为在适当的浓度下，它们可以诱导弱酸的典型植物非生物胁迫响应，从而诱导植物适应环境并增强非生物胁迫耐受性。腐殖酸如短链有机酸会降低BCECF探针荧光显示的细胞内pH。腐殖酸促进的胞质pH下降不是暂时的。我们观察到高水平的蛋白激酶，与细胞压力感应和转录信号转导相关的转录因子有关。腐殖酸可以被认为是一种化学引发剂，因为在适当的浓度下，它们可以诱导弱酸的典型植物非生物胁迫响应，从而诱导植物适应环境并增强非生物胁迫耐受性。