Plant-Microbe Interaction and Rhizosphere Biology Lab, ICAR-NBAIM, Kushmaur, Mau, U.P, India.
Department of Botany and Microbiology, College of Science, King Saud University, P.O. Box 2455, 11451, Riyadh, Saudi Arabia.
Appl Biochem Biotechnol. 2024 Jul;196(7):3949-3973. doi: 10.1007/s12010-023-04730-4. Epub 2023 Oct 4.
Heavy metals (HMs) at a concentration above the threshold level act as environmental pollutants and very often threaten the agricultural productivity globally. Finding affordable and environmentally sustainable deliverables to address this issue is therefore a top focus. Phytohormones alleviate the HMs-induced toxicity and positively influence the plant growth. Considering the importance of phytohormones, the present study aimed to assess the effect of 24-epibrassinolide (24-EBL; 10 µM) as seed soaking treatment on growth performance of Zea mays (L.) contaminated separately with increasing concentrations (50-400 mg.kg) of lead (Pb) and cadmium (Cd). With increasing metal concentrations, growth and plant biometric criteria were reduced. For instance, Cd at 400 mg.kg soil reduced the germination efficiency (56%), root (77%) and shoot (69%) dry weight, total chlorophyll (64%), and carotenoid content (45%). Contrarily, both HMs caused increase in stress biomarkers and antioxidant enzymes in seedling. However, exogenous administration of 24-EBL significantly enhanced the growth attributes, photosynthetic pigments, proline, MDA, and antioxidant enzyme activity while reducing the harmful effects of HMs stress on Z. mays. For instance, 24-EBL (10 µM) improved the germination percentage, root biomass, chl a, chl b, total chlorophyll, and carotenoid content by 16, 21, 17, 34, 18, and 15%, respectively, in 50 mg.Pb.kg soil-treated Z. mays plants. Furthermore, the amounts of proline, MDA, and antioxidant enzymes in foliage of Z. mays were interestingly and dramatically lowered by 24-EBL application. Uptake of metals in plant organs was significantly reduced when 24-EBL was applied to Pb- and Cd-treated Z. mays. The recent findings help us better understand how 24-EBL regulates growth and development of Z. mays as well as how it boosts HMs' resilience, which could increase the possibility of employing 24-EBL to increase Z. mays productivity. Thus, the present findings confirmed the potentiality of pre-soaking the seed in 24-EBL solution that neutralizes the toxic effects of heavy metals in Z. mays plants. Therefore, it is suggested that applying phytohormones including 24-EBL in removal of heavy metal stress in plants is the best possible solution in sustainable agriculture.
重金属（HM）在浓度超过阈值水平时会作为环境污染物，并且经常对全球农业生产力构成威胁。因此，寻找负担得起且环境可持续的解决方案是当务之急。植物激素可以减轻 HM 诱导的毒性，并对植物生长产生积极影响。考虑到植物激素的重要性，本研究旨在评估 24-表油菜素内酯（24-EBL；10µM）作为种子浸泡处理对分别用不同浓度（50-400mg.kg）铅（Pb）和镉（Cd）污染的玉米（Zea mays（L.））生长性能的影响。随着金属浓度的增加，生长和植物生物计量标准降低。例如，土壤中 400mg.kg 的 Cd 降低了发芽效率（56%）、根（77%）和茎（69%）干重、总叶绿素（64%）和类胡萝卜素含量（45%）。相反，两种 HM 都会导致幼苗中的应激生物标志物和抗氧化酶增加。然而，外源施用 24-EBL 可显著提高生长特性、光合色素、脯氨酸、MDA 和抗氧化酶活性，同时减轻 HM 胁迫对 Z. mays 的有害影响。例如，24-EBL（10µM）分别提高了 50mg.Pb.kg 土壤处理的 Z. mays 植物的发芽率、根生物量、chl a、chl b、总叶绿素和类胡萝卜素含量 16%、21%、17%、34%、18%和 15%。此外，24-EBL 处理显著降低了 Z. mays 叶片中的脯氨酸、MDA 和抗氧化酶的含量。当将 24-EBL 应用于 Pb 和 Cd 处理的 Z. mays 时，植物器官对金属的吸收明显减少。本研究结果有助于我们更好地了解 24-EBL 如何调节 Z. mays 的生长发育，以及它如何增强 HM 的抗逆性，这可能增加在 Z. mays 中使用 24-EBL 提高生产力的可能性。因此，本研究结果证实了在 24-EBL 溶液中浸泡种子的潜力，可以中和 Z. mays 植物中重金属的毒性作用。因此，建议在可持续农业中，应用包括 24-EBL 在内的植物激素来去除重金属胁迫是最好的解决方案。
