Avaliação do uso de trigo -triticum aestivum e da soja - glycine max como fitorremediadores em solos contaminados com fluoreto

Abstract

Soybean (Glycine max) is used for various purposes, however, its importance lies in the fact that its grains provide large volumes of bran for animal feed and oil for human food. Wheat (Triticum aestivum), on the other hand, provides the most nutritious of all bread-making flours, with a high protein content. Wheat and soybean plants are called hyperaccumulators, as they have the capacity to absorb fluorides by the roots, which are stored in them or are transported and accumulated in the aerial parts. Soybean and wheat plants were subjected to a treatment with 40mg and 80mg of sodium fluoride dissolved in one liter of water and to a control that contained only water. The pollutant was used on the first day as soon as the plants were allowed to germinate in pots, in the greenhouse of the Department of Biological Sciences, from May to July 2004. They were daily watered with only water until the end of the study, with the aim of to evaluate the growth of these two cultures in the absence and presence of fluorides. Monthly and over a three-month period, 24 plants were harvested, 8 for each treatment, of which half were used to extract chlorophyll and the other half were used to measure different growth parameters. The main symptoms observed were chlorosis and necrosis in the leaves, which led to a reduction in the concentration of chlorophyll. This fact may have probably influenced growth, as it reduced significantly in the last two months of the study. Fluoride did not influence the height growth of the plants under study, while the relative growth rate and chlorophyll concentration were the most affected parameters. Wheat developed better in the 80mg/l treatment and less in 40mg/l, while soy had greater growth in the control and lesser in 80mg/l. It is recommended that a similar study be carried out with different crops and the planting of these in areas close to industries and factories that emit fluorides, as they seem to have the capacity to absorb fluoride from the soil