GIULIETTI Ana Maria
Removal of Phenol by Alfalfa Plants (Medicago sativa L.) Grow in Hydroponics and its Effect on Some Physiological Parameters
FLOCCO, C.G; LOBALBO,A.; CARRANZA,P.; GIULIETTI A.M.
Año: 2002 vol. 22 p. 43 - 43
Résumé / Abstract The plant-assisted removal of phenol, with special emphasis on the effects of this compound on some plant´s physiological parameters, was investigated. Hydroponic cultures of alfalfa (Medicago sativa L., var. Romagnola) were employed as a model system. These cultures were exposed to two phenol concentrations: 100 and 500 mg/l. A first order kinetic approach was used to describe the removal of phenol from the solution. After 30 days of cultivation, the initial amount of phenol (100 mg/l) was reduced to non-detectable levels in the presence of plants. In the absence of plants, 20% of phenol remained in the solution. The half-life of phenol was reduced from 7.2 to 4.5 days in the presence of plants. After 25 days, the initial amount of 500 mg/l of phenol was reduced to non-detectable levels in the presence of plants not previously exposed to phenol and to approximately 20% with plants previously exposed to the contaminant. In the absence of plants, almost 40% remained in the solution. The presence of plants reduced the half-life of phenol from 18.3 days to 10.4 in the case of plants previously exposed and to 7.8 days in the case of plants without previous contact. Chlorophyll contents in alfalfa leaves of plants exposed to 100 mg/l of phenol were similar to those of control plants and a decrease in total chlorophyll content was observed when plants were exposed to 500 mg/l of phenol. The activity of soluble peroxidases of the roots increased in the presence of 100 mg/l of phenol but the amount of 500 mg/l had a negative effect on the peroxidase fraction. No changes were observed in the case of the ionically-bound cell wall fraction. The growth index of the plants exposed to 100 mg/l of phenol was comparable to that of non-exposed plants, while this parameter was negatively affected in the case of plants exposed to 500 mg/l of phenol. Although alfalfa plants were able to survive an exposure to 500 mg/l of phenol, their physiological parameters and their removal capacity were negatively affected. Revue / Journal Title Acta biotechnologica ISSN 0138-4988 CODEN ACBTDD