The co-application of exogenous 100 µM melatonin (MT) and 100 µM salicylic acid (SA) on 21-day-old safflower seedlings grown in the presence of cadmium (Cd, 100 µM) toxicity was investigated. The application of MT, SA, or MT + SA efficiently improved toxicity symptoms and declined Cd toxicity as shown by a considerable rise in plant biomass production and chlorophyll content accompanied by decreased level of oxidative stress markers. In Cd stressed plants, the simultaneous application of MT and SA led to sharp decreases in MDA and H2O2 amounts (61.04 and 49.11%, respectively), related to plants treated with Cd alone. With respect to the control, a 41 and 48% increment in reduced glutathione (GSH) and ascorbate (ASC) content was recorded in Cd-treated seedlings. Though, with the addition of MT, SA, or MT + SA, the content of GSH and ASC increased more. The application of MT, SA, or MT + SA caused a sharp induction in phytochelatin content of the leaves of Cd-treated seedlings, while in roots, the highest PC content was recorded only in the presence of MT, which was about 1.8-fold greater than in plant treated with Cd alone. The activity of enzymes responsible for the ascorbate-glutathione cycle and glyoxalase system considerably improved by using MT, SA, or the combination of MT and SA. Our findings suggest a possible synergic interaction between MT and SA in tolerating Cd toxicity by reducing Cd uptake, improving chlorophyll biosynthesis and accelerating ascorbate-glutathione cycle as well as the modulation of glyoxalase system.

研究了外源100 µM褪黑素（MT）和100 µM水杨酸（SA）在有镉（Cd，100 µM）毒性的条件下生长的21天大红花幼苗上的共同应用。MT，SA或MT + SA的应用有效改善了毒性症状，降低了Cd毒性，这表现为植物生物量产量和叶绿素含量显着增加，同时氧化应激标志物水平降低。在镉胁迫的植物中，MT和SA的同时施用导致MDA和H2O2含量急剧下降（分别为61.04％和49.11％），这与仅用Cd处理的植物有关。关于对照，在镉处理的幼苗中，谷胱甘肽（GSH）和抗坏血酸（ASC）含量减少了41％和48％。不过，除了MT，SA或MT + SA，GSH和ASC的含量增加更多。施用MT，SA或MT + SA会导致对Cd处理过的幼苗的叶片中植物螯合素含量的强烈诱导，而在根部，仅在MT存在下记录到最高的PC含量，约为1.8倍比单独使用镉处理的植物更大。通过使用MT，SA或MT和SA的组合，可显着提高负责抗坏血酸-谷胱甘肽循环和乙二醛酶系统的酶的活性。我们的研究结果表明，MT和SA之间可能通过降低Cd吸收，改善叶绿素的生物合成和加速抗坏血酸-谷胱甘肽循环以及调节乙二醛酶系统来协同耐受Cd毒性。或MT + SA导致对Cd处理的幼苗的叶片中植物螯合素含量的强烈诱导，而在根部，仅在MT存在下记录到最高的PC含量，这比Cd处理的植物高约1.8倍独自的。通过使用MT，SA或MT和SA的组合，可显着提高负责抗坏血酸-谷胱甘肽循环和乙二醛酶系统的酶的活性。我们的研究结果表明，MT和SA之间可能通过降低Cd吸收，改善叶绿素的生物合成和加速抗坏血酸-谷胱甘肽循环以及调节乙二醛酶系统来协同耐受Cd毒性。或MT + SA导致对Cd处理的幼苗的叶片中植物螯合素含量的强烈诱导，而在根部，仅在MT存在下记录到最高的PC含量，这比Cd处理的植物高约1.8倍独自的。通过使用MT，SA或MT和SA的组合，可显着提高负责抗坏血酸-谷胱甘肽循环和乙二醛酶系统的酶的活性。我们的研究结果表明，MT和SA之间可能通过降低Cd吸收，改善叶绿素的生物合成和加速抗坏血酸-谷胱甘肽循环以及调节乙二醛酶系统来协同耐受Cd毒性。通过使用MT，SA或MT和SA的组合，可显着提高负责抗坏血酸-谷胱甘肽循环和乙二醛酶系统的酶的活性。我们的研究结果表明，MT和SA之间可能通过降低Cd吸收，改善叶绿素的生物合成和加速抗坏血酸-谷胱甘肽循环以及调节乙二醛酶系统来协同耐受Cd毒性。通过使用MT，SA或MT和SA的组合，可显着提高负责抗坏血酸-谷胱甘肽循环和乙二醛酶系统的酶的活性。我们的研究结果表明，MT和SA之间可能通过降低Cd吸收，改善叶绿素的生物合成和加速抗坏血酸-谷胱甘肽循环以及调节乙二醛酶系统来协同耐受Cd毒性。