ENVR 100 |
| Manganese toxicity symptoms are more often observed in crops at early stages of growth since Mn2+ can be easily acummulated in the surface soil. The objectives of this study were to evalute some of the popular rotation crops grown in Hungary for tolerance to high external Mn2+ levels and to determine the critical tissue concentration for Mn2+ toxicity during early stages of growth. Indicator plants of sunflower (Helianthus annuus L.), tobacco (Nicotiana tabacum L.) and triticale (XTriticosecale W.) were grown with 10.2 to 70.0 mg Mn2+ kg-1 and were grown for 52d., 103d. and 224d. The minimum Mn2+ concentration required in soil nutrient contents was 42.5 mg kg-1 for sunflower, 22.1 mg kg-1 for tobacco and 10.24 mg kg-1 for triticale. Sunflower, tobacco and triticale achieved optimum growth 48.0 to 65.0 mg Mn2+ kg-1,; 29.3 to 31.3 mg Mn2+ kg-1 and 28.7 to 29.6 mg Mn2+ kg-1. Critical toxic shoot Mn2+ concentration at early stages of growth was 206.7 mg kg-1 in sunflower, 2,287.5 mg kg-1 in tobacco and 412.5 mg kg-1 in triticale. Our results demonstrate that the tolerance to high external Mn2+ (sunflower: >56.2 mg kg-1, tobacco: >30.0 mg kg-1, triticale: >30.2 mg kg-1) and the critical tissue Mn2+ levels for toxicity varied significantly among crop species tested. |
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Environmental Contaminants: Low-Level and Complex Mixtures
1:30 PM-4:50 PM, Wednesday, August 22, 2007 Boston Park Plaza -- Stanbro Rm, Oral
Division of Environmental Chemistry |