Changes in subcellular distribution and antioxidant compounds involved in Pb accumulation and detoxification in Neyraudia reynaudiana

• Published in: Environmental science and pollution research international Vol. 23; no. 21; pp. 21794 - 21804
• Main Authors: Zhou, Chuifan, Huang, Meiying, Li, Ying, Luo, Jiewen, Cai, Li ping
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.11.2016; Springer Nature B.V
• Subjects: Antioxidants; Antioxidants - metabolism; Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Bioaccumulation; Cell division; Cell Wall - metabolism; Detoxification; Earth and Environmental Science; Ecotoxicology; Environment; Environmental Chemistry; Environmental Health; Environmental science; Enzymatic activity; Enzymes; Flowers & plants; Heavy metals; Inactivation, Metabolic; Lead; Lead - metabolism; Lead - toxicity; Leaves; Malondialdehyde - metabolism; Mining; Neyraudia reynaudiana; Oxidative stress; Photosynthesis - drug effects; Physiology; Phytochelatins - metabolism; Plant Leaves - metabolism; Plant resistance; Plant Roots - metabolism; Poaceae - drug effects; Poaceae - metabolism; Pollution; Research Article; Roots; Seedlings; Seedlings - drug effects; Soil Pollutants - metabolism; Soil Pollutants - toxicity; Studies; Toxicity; Waste Water Technology; Water conservation; Water Management; Water Pollution Control; Lead; Ultrastructure; Subcellular distribution; Phytochelatin; Antioxidative defense system; Neyraudia reynaudiana
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-016-7362-1

The effects of increasing concentrations of lead (Pb) on Pb accumulation, subcellular distribution, ultrastructure, photosynthetic characteristics, antioxidative enzyme activity, malondialdehyde content, and phytochelatin contents were investigated in Neyraudia reynaudiana seedlings after a 21-day exposure. A Pb analysis at the subcellular level showed that the majority of Pb in the roots was associated with the cell wall fraction, followed by the soluble fraction. In contrast, the majority of the Pb in the leaves was located in the soluble fraction based on transmission electron microscopy and energy dispersive X-ray analyses. Furthermore, high Pb concentrations adversely affected N. reynaudiana cellular structure. The changes in enzyme activity suggested that the antioxidant system plays an important role in eliminating or alleviating Pb toxicity, both in the roots and leaves of N. reynaudiana. Additionally, the phytochelatin contents in the roots and leaves differed significantly between Pb-spiked treatments and control plants. Our results provide strong evidence that cell walls restrict Pb uptake into the protoplasm and establish an important protective barrier. Subsequent vacuolar compartmentalization in leaves could isolate Pb from other substances in the cell and minimize Pb toxicity in other organelles over time. These results also demonstrated that the levels of antioxidant enzymes and phytochelatin in leaves and roots are correlated with Pb toxicity. These detoxification mechanisms promote Pb tolerance in N. reynaudiana.