Involvement of polyamines in adaptation of Potamogeton crispus L. to cadmium stress

• Published in: Aquatic toxicology 2010-11, Vol.100 (3), p.282-288
• Main Authors: Yang, Haiyan, Shi, Guoxin, Wang, Hongxia, Xu, Qinsong
• Format: Article
• Language: English
• Subjects: Adaptation, Physiological; Amine Oxidase (Copper-Containing) - metabolism; Animal, plant and microbial ecology; Applied ecology; Ascorbic Acid - metabolism; Biological and medical sciences; Cadmium; Cadmium - toxicity; Chloroplasts - drug effects; Chloroplasts - metabolism; Chloroplasts - ultrastructure; Ecotoxicology, biological effects of pollution; Fundamental and applied biological sciences. Psychology; General aspects; Glutathione - metabolism; Oxidoreductases Acting on CH-NH Group Donors - metabolism; Polyamine Oxidase; Polyamines; Polyamines - metabolism; Potamogeton crispus; Potamogetonaceae - drug effects; Potamogetonaceae - physiology; Potamogetonaceae - ultrastructure; Soil Pollutants - toxicity
• ISSN: 0166-445X; 1879-1514
• DOI: 10.1016/j.aquatox.2010.07.026

The effects of increasing concentrations of cadmium (Cd) on the ultrastructure, Cd accumulation, generation of O 2 −, contents of ascorbate (AsA), reduced glutathione (GSH) and polyamines (PAs), as well as the activities of polyamine oxidase (PAO) (EC 1.5.3.3) and diamine oxidase (DAO) (EC 1.4.3.6) were investigated in the leaves of Potamogeton crispus. Cd exposure resulted in significant damage in chloroplasts and mitochondria, suggesting that Cd hastened the senescence of the tested plants. The accumulation of Cd was found to increase in a concentration-dependent manner, accompanied by increased production of O 2 −. AsA content increased progressively up to 70 μM Cd, followed by a decline at higher concentration. GSH content slightly increased up to 70 μM Cd and then declined. In addition, Cd treatment increased the putrescine (Put) content, while decreasing spermidine (Spd) and spermine (Spm) contents, which reduced the ratio of free (Spd + Spm)/Put in the leaves. PS-conjugated PAs changed in the same pattern as free PAs, while PIS-bound PAs was different. PIS-bound Put content enhanced with the increase of Cd concentration up to 50 μM and then decreased, and PIS-bound Spd and Spm contents decreased to a lesser extent. Moreover, the activities of PAO and DAO increased significantly with the increase of the Cd concentrations, reaching the peak values at 70 μM Cd. Our results suggested that certain PAs and PAs forms could play a significant role in the adaptation mechanism of P. crispus under Cd stress.