Periyar University, Department of Biotechnology, Plant Genetic Engineering and Molecular Biology Lab, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India.
Periyar University, Department of Biotechnology, Plant Genetic Engineering and Molecular Biology Lab, Periyar Palkalai Nagar, Salem, 636 011, Tamil Nadu, India.
Chemosphere. 2017 Mar;171:544-553. doi: 10.1016/j.chemosphere.2016.12.092. Epub 2016 Dec 20.
The present study was designed to assess the physiological and biochemical changes in roots and shoots of the herb Acalypha indica grown under hydroponic conditions during exposure to lead (Pb) (100-500 mg L) for 1-12 d. The accumulation of Pb by A. indica plants was found to be 121.6 and 17.5 mg g dry weight (DW) in roots and shoots, respectively, when exposed to a Pb concentration of 500 mg L. The presence of Pb ions in stem, root and leaf tissues was confirmed by scanning electron microscope (SEM) and Energy-dispersive X-ray spectroscopy (EDX) analyses. Concerning the activity of antioxidant enzymes, viz., peroxidase (POX) catalase (CAT) and ascorbate peroxidase (APX), they were induced at various regimes during 5, 8 and 12 d of Pb exposure in both the leaves and roots than untreated controls. Lead treatment increased superoxide dismutase (SOD) activity in both the leaf and root tissues over control, irrespective of the duration of exposure. Anew, it was observed that Pb treatments induced variations in the number and intensity of protein bands. Random amplified polymorphic DNA (RAPD) results show that the Pb treatment caused genotoxicity on DNA molecules as evidenced by the amplification of new bands and the absence of normal DNA amplicons in treated plants. Results confirm that A. indica is a Pb accumulator species, and the antioxidants might play a crucial role in the detoxification of Pb-induced toxic effects.
本研究旨在评估水培条件下暴露于铅（Pb）（100-500mg/L）1-12d 后，叶下珠（Acalypha indica）根和茎的生理和生化变化。当暴露于 500mg/L Pb 浓度时，A.indica 植物根部和地上部分的 Pb 积累量分别为 121.6 和 17.5mg/g 干重（DW）。扫描电子显微镜（SEM）和能谱分析（EDX）分析证实了 Pb 离子存在于茎、根和叶片组织中。关于抗氧化酶活性，即过氧化物酶（POX）、过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX），它们在 Pb 暴露 5、8 和 12d 期间在叶片和根部的不同时间点被诱导，而未处理的对照中则没有。Pb 处理增加了叶片和根组织中超氧化物歧化酶（SOD）的活性，而与暴露时间无关。此外，还观察到 Pb 处理诱导了蛋白质条带的数量和强度的变化。随机扩增多态性 DNA（RAPD）结果表明，Pb 处理导致 DNA 分子的遗传毒性，证据是新条带的扩增和处理植物中正常 DNA 扩增子的缺失。结果证实，叶下珠是一种 Pb 积累物种，抗氧化剂可能在 Pb 诱导的毒性效应解毒中发挥关键作用。
