Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India.
Plant Physiology Section, Department of Botany, Aligarh Muslim University, Aligarh, 202002, India.
Plant Physiol Biochem. 2023 Sep;202:107981. doi: 10.1016/j.plaphy.2023.107981. Epub 2023 Aug 21.
Nickel (Ni) at a toxic level (80 mg kg of soil) adversely affects the crop performance of fenugreek (Trigonella foenum-graecum L.). Melatonin (MEL), a potent plant growth regulator, is ascribed to offer promising roles in heavy metal stress alleviation. In this study, different doses viz. 0, 25, 50, 75 and 100 μM of MEL were administered to plants through foliage under normal and Ni-stress conditions. The experiment unveiled positive roles of MEL in enhancing root-shoot lengths, fresh-dry weights, seed yield and restoring photosynthetic efficiency assessed in terms of higher F/F, YII, qP, and lower NPQ values in plants exposed to Ni (80 mg kg). MEL supplementation (at 75 μM) effectively restricted Ni accumulation and regulated oxidative stress via modulation of MDA, O, HO and NO generation, most prominently. Besides, MEL at 75 μM more conspicuously perked up the activities of antioxidant enzymes like SOD, POX, CAT and APX by 15.7, 20.0, 14.5 and 16.5% higher than the Ni-exposed plants for effective ROS scavenging. Likewise, MEL at 75 μM also efficiently counteracted Ni-generated osmotic stress, through an upscaled accumulation of proline (19.6%) along with the enhancement in the concentration of total phenols (13.6%), total tannins (11.2%), total flavonoids (25.5%) and total alkaloids (19.2%) in plant's leaves. Furthermore, under 80 mg kg Ni stress, MEL at 75 μM improved the seed's trigonelline content by 40.1% higher compared to Ni-disturbed plants, upgrading the pharmacological actions of the plant. Thus, the present study deciphers the envisaged roles of MEL in the alleviation of Ni stress in plants to enhance overall crop productivity.
镍（Ni）在有毒水平（80mgkg 土壤）下会对葫芦巴（Trigonella foenum-graecum L.）的作物表现产生不利影响。褪黑素（MEL）是一种有效的植物生长调节剂，被认为在缓解重金属胁迫方面具有有前途的作用。在这项研究中，通过叶面处理向正常和 Ni 胁迫条件下的植物施用不同剂量的 MEL，剂量分别为 0、25、50、75 和 100μM。实验结果表明，MEL 能有效增强根长、根鲜重、根干重、地上部分鲜重、地上部分干重、种子产量，恢复在 80mgkg Ni 暴露下植物的光合效率，表现在 F/F、YII、qP 较高，NPQ 值较低。MEL 处理（75μM）能有效抑制 Ni 积累，并通过调节 MDA、O、HO 和 NO 的生成来调节氧化应激，作用最为明显。此外，MEL 在 75μM 下通过提高 SOD、POX、CAT 和 APX 等抗氧化酶的活性（比 Ni 暴露的植物高 15.7、20.0、14.5 和 16.5%），更显著地增强了对 ROS 的清除作用。同样，MEL 在 75μM 下还能有效抵抗 Ni 产生的渗透胁迫，通过提高脯氨酸（19.6%）的积累和增强总酚（13.6%）、总单宁（11.2%）、总类黄酮（25.5%）和总生物碱（19.2%）的浓度来提高植物叶片的抗氧化能力。此外，在 80mgkg Ni 胁迫下，MEL 在 75μM 下处理的种子中瓜氨酸含量比受 Ni 干扰的植物提高了 40.1%，从而提高了植物的药理学作用。因此，本研究阐明了 MEL 在缓解植物 Ni 胁迫以提高整体作物生产力方面的预期作用。
