Department of Biology, Institute of Gradute Studies, Batman University, Batman, Türkiye.
Department of Food Process, Technical Science Vocational School, Batman University, Batman, Türkiye.
BMC Plant Biol. 2024 Sep 30;24(1):897. doi: 10.1186/s12870-024-05600-9.
Heavy metal toxicity adversely affects plants by changing physiological, biochemical, and molecular mechanisms. Lead (Pb) is one of the most common heavy metal pollutants. Hence this study investigated changes caused by exogenous methyl jasmonate (MeJA; 20 and 100 µM) and salicylic acid (SA; 2 and 20 mM) elicitors in local Karacadağ rice exposed to Pb stress (0, 100, and 400 ppm). The effects of elicitors on photosynthetic pigment content (chlorophyll a, chlorophyll b, and total carotenoid), proline, malondialdehyde (MDA), total phenolic and flavonoid, Pb, and total protein contents in stressed plants were evaluated. All parameters studied increased and decreased at varying rates in the treatment groups compared to the Pb-free group (control), indicating that rice plants were affected by Pb stress. The elicitors (MeJA, SA, and MeJA + SA) were applied by foliar spraying. The elicitor treatments increased photosynthetic pigment content, total protein, proline, total flavonoid, and phenolic contents depending on the elicitor type and concentration. MDA and Pb contents, increasing with Pb toxicity, decreased with elicitor treatments, and the stress degree was reduced. When the elicitors were compared, SA was more effective than MeJA in total flavonoid content at 400 ppm Pb toxicity. However, MeJA was more effective in photosynthetic pigment contents, MDA, total protein, Pb, total phenolic, and proline contents. The best results for all parameters examined in rice plants exposed to Pb toxicity were obtained from the 400 ppm Pb + 2 mM SA + 20 µM MeJA treatment group. In conclusion, this study showed that the combined application of MeJA + SA alleviated the harmful effects of Pb by reducing MDA and increasing photosynthetic pigments, total protein, proline, and secondary metabolites, especially at high Pb concentrations. Consequently, this study demonstrated that the combined use of MeJA and SA in rice plants eliminated the negative effects of stress quite effectively, even at high Pb concentrations. Therefore, future studies should focus on the synergistic application of different elicitors to better understand the effects of heavy metal toxicity on plant growth and development.
重金属毒性通过改变生理、生化和分子机制对植物产生不利影响。铅（Pb）是最常见的重金属污染物之一。因此，本研究调查了外源茉莉酸甲酯（MeJA；20 和 100 μM）和水杨酸（SA；2 和 20 mM）激发子在局部卡拉卡达格水稻暴露于 Pb 胁迫（0、100 和 400 ppm）下引起的变化。激发子对受胁迫植物中光合色素含量（叶绿素 a、叶绿素 b 和总类胡萝卜素）、脯氨酸、丙二醛（MDA）、总酚和类黄酮、Pb 和总蛋白含量的影响进行了评估。与不含 Pb 的组（对照）相比，所有研究参数在处理组中以不同的速率增加和减少，表明水稻植株受到 Pb 胁迫的影响。通过叶面喷施施加激发子（MeJA、SA 和 MeJA+SA）。激发子处理根据激发子类型和浓度增加了光合色素含量、总蛋白、脯氨酸、总类黄酮和总酚含量。随着 Pb 毒性的增加，MDA 和 Pb 含量增加，随着激发子处理的进行，含量降低，降低了胁迫程度。在比较激发子时，SA 在 400 ppm Pb 毒性下对总类黄酮含量的效果比 MeJA 更有效。然而，MeJA 在光合色素含量、MDA、总蛋白、Pb、总酚和脯氨酸含量方面更有效。在暴露于 Pb 毒性的水稻植株中，所有参数的最佳结果都来自于 400 ppm Pb+2 mM SA+20 μM MeJA 处理组。总之，本研究表明，MeJA+SA 的联合应用通过降低 MDA 和增加光合色素、总蛋白、脯氨酸和次生代谢物来减轻 Pb 的有害影响，特别是在高 Pb 浓度下。因此，本研究表明，MeJA 和 SA 在水稻植株中的联合使用可以有效地消除应激的负面影响，即使在高 Pb 浓度下也是如此。因此，未来的研究应集中在不同激发子的协同应用上，以更好地了解重金属毒性对植物生长和发育的影响。
