College of Life Sciences, Northwest A&F University, Yangling 712100, China.
College of Agronomy, Northwest A&F University, Yangling 712100, China.
Biomolecules. 2020 Jan 16;10(1):147. doi: 10.3390/biom10010147.
Pot experiments were conducted to investigate the probable beneficial role of the individual as well as combined application of kinetin (50 μM Kn) and spermidine (200 μM Spd) on under cadmium (Cd) stress. Cd treatment reduced growth by declining the content of chlorophylls and carotenoids, photosynthesis, and gas exchange parameters. Exogenously, Kn and Spd application enhanced the photosynthetic parameters and up-regulated the antioxidant system by improving the activities of antioxidant enzymes and the content of non-enzymatic components. In addition, the application of Kn and Spd resulted in significant improvement in the content of sugars, proline, and glycine betaine, ameliorating the decline in relative water content. Oxidative stress parameters including hydrogen peroxide, superoxide, lipid peroxidation, lipoxygenase activity, and electrolyte leakage increased due to Cd stress; however, the application of Kn and Spd imparted a significant decline in all these parameters. Further, reduced Cd uptake was also observed due to Kn and Spd application. Total phenols and flavonoids also increased due to Kn and Spd treatments under normal as well as Cd stress conditions, which may have further helped with the elimination of reactive oxygen species. Reduction in the activity of nitrate reductase and the content of nitrogen was ameliorated due to the exogenous application of Kn and Spd. Therefore, the exogenous application of Kn and Spd benefited counteracting the damaging effects of Cd stress by up-regulating the tolerance mechanisms, including antioxidant and osmolyte metabolism.
采用盆栽实验研究了单独及联合施用激动素（50 μM Kn）和亚精胺（200 μM Spd）对镉（Cd）胁迫下的可能有益作用。Cd 处理通过降低叶绿素和类胡萝卜素、光合作用和气体交换参数的含量来抑制生长。外源施用 Kn 和 Spd 提高了光合作用参数，并通过提高抗氧化酶的活性和非酶成分的含量来上调抗氧化系统，从而上调抗氧化系统。此外，Kn 和 Spd 的应用导致糖、脯氨酸和甘氨酸甜菜碱的含量显著增加，从而减轻相对水含量的下降。由于 Cd 胁迫，过氧化氢、超氧化物、脂质过氧化、脂氧合酶活性和电解质渗漏等氧化应激参数增加；然而，Kn 和 Spd 的应用显著降低了所有这些参数。此外，由于 Kn 和 Spd 的应用，Cd 的摄取也减少了。由于 Kn 和 Spd 处理，总酚类和类黄酮含量也增加，这可能有助于清除活性氧。由于外源施用 Kn 和 Spd，硝酸还原酶的活性和氮的含量降低得到了改善。因此，外源施用 Kn 和 Spd 有利于通过上调包括抗氧化和渗透物质代谢在内的耐受机制来抵消 Cd 胁迫的破坏作用。
