Uso da técnica de espectroscopia para a análise da interação entre HPAs e o sistema fotossintético da alface (lactuca sativa, l)

Abstract

Aromatic Polycyclic Hydrocarbons (HPAs) are nonpolar organic compounds formed exclusively of carbon and hydrogen atoms and organized as aromatic fused rings. They are carcinogenic pollutants origined from incomplete combustion and/or pyrolysis of organic matter, being the burning of fossil fuels one of the main sources of these contaminants in the atmosphere. The continuous presence of these contaminants in the environment is a direct consequence of their low water solubility and also their association with soil and sediment organic matter, leading to the incorporation of these substances at various levels of the food chain. Considering that food intake is the most direct means for human exposure to various harmful substances, the present study evaluated possible interactions of benzo (a) pyrene obsrotion by lettuce (Lactuca sativa, L.) and their possible influences on its physiological structure and photosynthetic apparatus. We used samples of lettuces that are in direct contact with water and/or nutrient solution containing different amounts/concentrations of benzo(a)pyrene as a contaminant. The concentrations are based on data obtained in previous works (OLIVEIRA et al., 2015; RODRIGUES, 2011; ROSE, 2017). As a probe technique for the analysis of photosynthetic apparatus influences, synchronized fluorescence spectroscopy (EFS) was chosen as a low cost and efficient technique. Another parameter evaluated was plant biometrics, which measures the size of shoots and roots in plants. The technique evaluates normal and irregular growth and the relationship of these stress-related changes/anomalies caused by the incorporation of contaminants. Experimental results showed that benzo(a)pyrene is capable of inducing significant changes in lettuce physiological and photosynthetic behavior. Thus, the presence of aromatic polycyclic hydrocarbons in the lettuce leaves and consequently in the chlorophyll extract has an influence on its development when comparing only the fluorescence intensity.