Department of Botany, University of Peshawar, Peshawar, 25120, Pakistan.
Department of Biology, College of Science, Princess Nourah bint Abdulrahman University, P.O. Box 84428, Riyadh, 11671, Saudi Arabia.
BMC Plant Biol. 2024 Feb 13;24(1):108. doi: 10.1186/s12870-024-04767-5.
Soil pollution with heavy metals has grown to be a big hassle, leading to the loss in farming production particularly in developing countries like Pakistan, where no proper channel is present for irrigation and extraction of these toxic heavy metals. The present study aims to ameliorate the damages caused by heavy metal ions (Hg-Mercury) on rapeseed (Brassica napus L.) via a growth regulator (α-tocopherol 150 mg/L) and thermopriming technique at 4 °C and 50 °C to maintain plant agronomical and physiological characteristics. In pot experiments, we designed total of 11 treatments viz.( T0 (control), T1 (Hg4ppm), T2 (Hg8ppm), T3 (Hg4ppm + 4 °C), T4 (Hg4ppm + 4 °C + tocopherol (150 m/L)), T5 (Hg4ppm + 50 °C), T6 (Hg4ppm + 50 °C + tocopherol (150 mg/L)), T7 (Hg8ppm + 4 °C), T8 (Hg8ppm + 4 °C + tocopherol (150 mg/L)), T9 (Hg8ppm + 50 °C), T10 (Hg8ppm + 50 °C + tocopherol (150 mg/L) the results revealed that chlorophyll content at p < 0.05 with growth regulator and antioxidant enzymes such as catalase, peroxidase, and malondialdehyde enhanced up to the maximum level at T5 = Hg4ppm + 50 °C (50 °C thermopriming under 4 ppm mercuric chloride stress), suggesting that high temperature initiate the antioxidant system to reduce photosystem damage. However, protein, proline, superoxide dismutase at p < 0.05, and carotenoid, soluble sugar, and ascorbate peroxidase were increased non-significantly (p > 0.05) 50 °C thermopriming under 8 ppm high mercuric chloride stress (T9 = Hg8ppm + 50 °C) representing the tolerance of selected specie by synthesizing osmolytes to resist oxidation mechanism. Furthermore, reduction in % MC (moisture content) is easily improved with foliar application of α-tocopherol and 50 °C thermopriming and 4 ppm heavy metal stress at T6 = Hg4ppm + 50 °C + α-tocopherol (150 mg/L), with a remarkable increase in plant vigor and germination energy. It has resulted that the inhibitory effect of only lower concentration (4 ppm) of heavy metal stress was ameliorated by exogenous application of α-tocopherol and thermopriming technique by synthesizing high levels of proline and antioxidant activities in maintaining seedling growth and development on heavy metal contaminated soil.
土壤重金属污染问题日益严重，尤其在巴基斯坦等发展中国家，导致农业生产损失严重，因为这些国家缺乏灌溉和提取这些有毒重金属的适当渠道。本研究旨在通过生长调节剂（α-生育酚 150mg/L）和 4°C 和 50°C 的热预处理技术来改善重金属离子（Hg-汞）对油菜（ Brassica napus L.）造成的损害，以维持植物的农艺和生理特性。在盆栽实验中，我们共设计了 11 种处理方法：（T0（对照）、T1（Hg4ppm）、T2（Hg8ppm）、T3（Hg4ppm+4°C）、T4（Hg4ppm+4°C+α-生育酚（150m/L））、T5（Hg4ppm+50°C）、T6（Hg4ppm+50°C+α-生育酚（150mg/L））、T7（Hg8ppm+4°C）、T8（Hg8ppm+4°C+α-生育酚（150mg/L））、T9（Hg8ppm+50°C）、T10（Hg8ppm+50°C+α-生育酚（150mg/L））。结果表明，叶绿素含量在 p<0.05 时，生长调节剂和抗氧化酶（如过氧化氢酶、过氧化物酶和丙二醛）的含量增加到最大值，在 T5=Hg4ppm+50°C（4ppm 氯化汞胁迫下 50°C 热预处理）时达到最高水平，表明高温启动抗氧化系统以减少光系统损伤。然而，蛋白质、脯氨酸、超氧化物歧化酶在 p<0.05，类胡萝卜素、可溶性糖和抗坏血酸过氧化物酶在 p>0.05 时增加不显著（p>0.05），这表明在 8ppm 高汞胁迫下（T9=Hg8ppm+50°C），所选物种通过合成渗透物来抵抗氧化机制，从而具有耐受性。此外，通过叶面喷施α-生育酚和 50°C 热预处理以及 T6=Hg4ppm+50°C+α-生育酚（150mg/L）处理，在 4ppm 重金属胁迫下，可湿性粉剂（MC）的百分比（水分含量）容易得到改善，显著提高了植物活力和发芽能量。结果表明，仅通过外源施加α-生育酚和热预处理技术，在重金属污染土壤上维持幼苗生长和发育，合成高水平脯氨酸和抗氧化活性，可减轻低浓度（4ppm）重金属胁迫的抑制作用。
