Influence of Cadmium Toxicity on Plant Growth and Nitrogen Uptake in Rice as Affected by Nitrogen Form

• Published in: Journal of plant nutrition 2008-01, Vol.31 (1-3), p.251-262
• Main Authors: Hassan, M.J, Zhang, G, Zhu, Z
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; ammonium nitrate; ammonium sulfate; application rate; Biological and medical sciences; cadmium; calcium nitrate; chlorophyll; Economic plant physiology; enzyme activity; fluorescence; Freshwater; Fundamental and applied biological sciences. Psychology; growth; heavy metals; hydroponics; Metabolism; Metabolism. Physicochemical requirements; nitrate reductase; nitrogen fertilizers; Nitrogen source; nutrient uptake; Nutrition. Photosynthesis. Respiration. Metabolism; Oryza sativa; photosynthesis; phytotoxicity; Plant physiology and development; rice; Soil and water pollution; soil pollution; Soil science; temporal variation
• ISSN: 0190-4167; 1532-4087
• DOI: 10.1080/01904160701853753

The influence of different nitrogen (N) fertilizers on plant growth, nitrate reductase (NR) activity, and cadmium (Cd) and N accumulation in Cd-stressed rice plants was studied in a hydroponic experiment. There were three N fertilizers, i.e., ammonium sulfate [(NH4)2SO4], ammonium nitrate (NH4NO3), and calcium nitrate [Ca(NO3)2]; and three Cd levels (0, 1, and 5 μ M). The reduction in all plant growth parameters, including photosynthetic rate, chlorophyll content, and fluorescence efficiency became more predominant with the prolonged stress exposure and increased Cd level. There was no significant difference in all these parameters among three N forms when no Cd was added into the culture solution. While for the plants exposed to Cd stress (1 and 5 μ M), the difference was significant among the three N forms. The least inhibition in growth parameters was recorded in (NH4)2SO4-fed plants and the most in Ca(NO3)2-fed plants. Cd stress significantly reduced NR activity and the reduced extent was dependent on N forms, with greatest reduction in Ca(NO3)2-fed plants and least in (NH4)2SO4-fed plants. Furthermore, a significant difference was noted among the three N forms in Cd and N concentrations and accumulation under Cd stress, with (NH4)2SO4 plants having less Cd uptake and more N accumulation. The differences in growth parameters, NR activity and Cd and N accumulation among N forms in Cd stressed plants indicate the possibility to alleviate Cd toxicity through reasonable utilization of N form in Cd contaminated soil.