AVALIAÇÃO DO POTENCIAL BIOINDICADOR DE Spondias mombin e Ricinus Communis EM EXPOSIÇÃO AO FLUORETO DE POTÁSSIO VIA CHUVA SIMULADA EM AMBIENTE CONTROLADO

Abstract

Air pollution in urban centers has been a major problem worldwide. Fluorine (F) in particular, is considered one of the most phytotoxic contaminants. Chronic exposure to high fluoride concentrations above the value established by the World Health Organization of 1.5 mg L-1 results in endemic diseases, such as dental fluorosis, skeletal and kidney problems, in addition to negatively impacting local biodiversity, especially for plants. Based on this, the present thesis aimed to determine the potential bioindicator of Spondias mombin and Ricinus communis with morphoanatomical, physiological evaluations and the contente determination of macronutrients and fluorine, after the experimental days with simulated rain with potassium fluoride. S. mombin and R. communis were exposed daily to potassium fluoride (KF) concentrations of 0; 10; 20 and 30 mg L-1 and 0; 1.5; 3; and 4.5 mg L-1. In S. mombin, it was possible to observe the various expressions of damage caused as necrosis throughout the leaf surface, thickness retraction of the mesophilic cells leading to the cell wall deformation and phenolic compounds accumulation. R. communis, on the other hand, had no visual symptoms during the 37 days of application of simulated rain with potassium fluoride for the control treatments, 1.5 and 3 mg L-1 of KF, however, the plants treated with 4.5 mg KF L-1 demonstrated formation of chlorotic pigments. In the anatomical evaluations, there were no changes in the root and leaf structure of R. communis for control treatments and 1.5 mg L-1 of KF. However, there was evidence of phenolic compounds accumulation in the treatment with 3 and 4.5 mg L-1 of KF. S. mombin performed sensitivity in all treatments with KF, since exposure to the pollutant triggered changes in visual structures, such as necrosis in all leaf areas, collapse of parenchymal cells and photosynthetic inhibition. On the other hand, R. communis showed tolerance to potassium fluoride at concentrations of 1.5 and 3.0 mg L-1, accumulating this compound in the roots and leaves.