Avaliação da poluição do ar com base nos aspectos anatômicos foliares e genotóxicos em Tradescantia pallida (Rose) D.r Hunt var. Purpurea

Abstract

As natural resources become scarce and technological advancement expands, the way the resources of the environment are used and the ways of preserving it become priority issues. Problems such as air, water and soil pollution, among others, become more and more common. The objective of this work was to analyze the quality of air in the microregion of Dourados based on anatomical and foliar aspects of Tradescantia pallida. The cities that comprise the microregions of the greater Dourados were analyzed, including: Dourados, Itaporã, Deodapolis, Douradina, Rio Brilhante, Nova Alvorada do Sul, Caarapó, Juti, Fatima do Sul, Gloria de Dourados, Vicentina, Jateí and the Bluão forest (control ) for four months during the year 2014 (May, July, September and November). In these cities were established two points that were marked with GPS Garminetrex LEGEND HCx. For the anatomical analyses, five leaves of different plants from each point from the studied cities were analyzed anatomically. The leaves were transversely sectioned the hand-free. The sections were clarified with 20% sodium hypochlorite and then submitted to the double staining process with Astra blue (1%) and Safranina (1%) Aqueous in proportion 9:1, being assembled in glycerin to 66%. The measurements of tissues and structures such as: Upper Cuticle (CS), inferior cuticle (CI), epidermis – Upper Face (ES), epidermis-inferior face (EI), Hypoderme (HIPO) and Mesophyll (MESO). For the stomatal analysis, paradéric sections of five different two-point leaves were performed in the cities. In each lamina, 10 fields were analyzed totaling 100 fields and the stomatal density was analyzed. The experiment was conducted in a completely randomized design in a factorial scheme, with 4 (times) x 12 (cities) + control with ten replications. The plots were subdivided in the time of 0 (zero), 60, 120 and 180 days. The data collected were submitted to analysis of variance. The averages were compared by the Tukey test 5% of probability and adjusted regression models using the highest R2 considering the minimum limit of 70%, with the aid of the statistical program. For the genotoxic analysis, floral buds were collected at different points. The vehicular flow was obtained from the counting of the vehicles that circulated through the collection point, three times a day being from 8:00 to 9:00 hours in the morning, from 11:00 to 12:00 hours and from 17:00 to 18:00 hours in the afternoon and compared with the data provided by IBGEDENATRAN. The young inflorescences of each point were collected and transported to the botanical Laboratory of the Faculty of Biological and Environmental Sciences (FCBA) of the Federal University of Greater Dourados (UFGD), Fixed in Carnoy (3:1) Alcohol and acetic acid solution for 24 hours and subsequently preserved in ethanol 70%. After fixation and preservation of the inflorescences, slides were made of the sampled buds. Five slides were prepared per point, which were analyzed in an optical microscope at an increase of 400x. The counting of existing Micronuclei was performed in a group of 300 tetrads per lamina. The Micronuclei frequency was calculated by the number of Micronuclei observed in 300 tétrades, divided by the total number of Laminas analyzed (100 lamines per collection point). The experiment was conducted in a completely randomized design in a 12 x 4 factorial scheme, with 12 cities and 4 seasons with five replications. The data measurements were subjected to analysis of variance and when significant, were compared by the Tukey test at 5% of with the assistance of the SAS statistical programme. The correlation between Micronuclei frequency (MCN), ambient temperature (Temp), relative air humidity (RH) and leaf temperature (º C) was determined by means of Pearson's correlation at 5% probability level. It can be observed the vehicular traffic in the cities of Dourados (± 559) and Rio Brilhante (± 674) showed the highest flows, demonstrating a different profile of the other cities. It was observed that there was a reduction in tissue thickness: upper face of the epidermis, hypoderme and Mesophyll in the plants located in the city of Dourados when compared to the control point. For the face of the inferior epidermis, the plants of the towns of Caarapó, Dourados and Fátima do Sul presented an increase when compared to the control point plants. For the inferior cuticle, the city of Dourados showed an increase in thickness up to ± 83 days of evaluation, after this, a continuous reduction of the same. For the upper cuticle, the cities of Caarapó and Vicentina showed an increase up to ± 68 days, after this period, a reduction of its thickness occurred. The city of Fátima do Sul for cuticle thickness presented reduced values after 68 days. For the other cities analyzed, no significant differences were observed for tissue thickness. Directly there was an increase in the stomatal density in Dourados (2880.18 mm2) and Rio Brilhante (3283.18 mm2) with the time of evaluation differing from the control (1508.9 mm2). It was observed that for the month of May, the cities of Vicentina (4.50), Dourados (3.66), Nova Alvorada Sul (3.33) and Rio Brilhante (3.00) obtained the highest frequencies of MCN when compared to the control (0.00). For the month of July the cities of Fatima do Sul (12.66), Dourados (10.00) presented the highest frequencies. In September, it highest frequency of MCN when compared to the other cities and control. Directly there was an increase in the frequency of MCN with the passing time of evaluations and the city of Dourados was the one that obtained a more expressive result among the cities analyzed. It is observed that the factors, ambient temperature and leaf temperature show significant and positive correlation with the frequency of MCN for the months of September and November and for relative humidity the correlation was negative and significant. In the present study, an inversely proportional relationship was observed when the relative humidity of the air was correlated with the frequency of micronucleus found in each analyzed city. It is noted that the increase in frequency occurs when there is a decrease in the relative humidity of the air. In view of the above, and in loco visits to these cities, it is observed that vehicular traffic is an important factor and is directly related to the observed variables, Directly interfering with air quality in these cities, and thus measures that minimize impacts should be taken to reduce the health damage of the population.