Physiological response of Vetiveria Zizanioides to cadmium stress revealed by Fourier transform infrared spectroscopy

Abstract

The present paper deals with the physiological response of the changes in chemical contents in the root, stem and leaf of Vetiveria zizanioides seedlings stressed by excess cadmium using Fourier transform infrared spectroscopy technique. Cadmium accumulation in plant and distribution in subcellular by atomic absorption spectroscopy were tested under different concentrations cadmium stress. The results show that low cadmium concentrations (<3 mg·L−1), the stem tissue of Vetiveria zizanioides can uses osmosis of organic substances (e.g., carbohydrates and amino acids) to improve cadmium tolerance. Organic acids secreted by the root of the plant could chelate cadmium, and the membrane lipid peroxidation of root, stem and leaf arise. It may be associated with cadmium tolerance threshold of Vetiveria zizanioides. In addition, the plant accumulated large amounts of cadmium, up to a maximum of 212.49 mg · kg−1(the shoot) and 290.59 mg · kg−1 dry weight (the root) on 10 days when the plant was treated with 7 mg·L−1 cadmium. The cadmium in the shoot (stem and leaf) usually increased with increasing cadmium concentration. Cadmium accumulated in leaves was mainly distributed in the cytoplasm, followed by the cell wall, and was least distributed in the mitochondria and chloroplasts. These studies demonstrated that the potential of Fourier transform infrared spectroscopy is the non-invasive and rapid technique for monitoring of the plants stressed with heavy metals, and Vetiveria zizanioides is suitable for phytoremediation of cadmium -contaminated soils.