Name: Kristian Rodolfo Santos
Type: MSc dissertation
Publication date: 28/02/2020
Advisor:
Name |
Role |
|---|---|
| Silvia Tamie Matsumoto | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Camilla Rozindo Dias Milanez | Co advisor * |
| Hildegardo Seibert França | Internal Examiner * |
| Josimar Ribeiro | Advisor * |
| Maria do Carmo Pimentel Batitucci | Internal Alternate * |
| Silvia Tamie Matsumoto | Advisor * |
| Stéfano Zorzal de Almeida | External Examiner * |
Summary: Pesticides are compounds that have a big variety of chemicals or biological products, made with the purpose of maxing out a biocidal action. It is known that its use is related with the world economy and the rising of agricultural productivity, however the risks of its use result in health issues and environmental damage, damaging the existing biota. Its effects can manifest in a short or long term, causing physiologic or genetic alterations of cellular structures. Therefore, many methods of evaluation have been developed to understand the properties and behavior of these chemicals. Thus, this paper aimed in evaluate the toxicogenetic potential of Clethodim herbicide, using the vegetable model Allium cepa. Seeds of Allium cepa were germinated in Petri dishes with the treatments concentrations of: C1, C2, C3, C4, C5 e C6 of herbicide until they reach approximately 1 to 2 mm of length. Trifluralin was used as positive control (C+) and distilled water as a negative control (C-). Were realized analysis of germination, root growth, evaluation of cytogenotoxic potential through cell cycle analysis (mitotic index, chromosomal (AC) and nuclear (AN) changes and assessment of oxidative stress by quantifying antioxidant enzymes; Superoxide dismutase (SOD), Catalase (CAT), Ascorbate peroxidase (APX). The data were analyzed by the Shapiro-Wilks test and analyzed by ANOVA, followed by comparison between the Tukey tests, Test T and Kruskal Wallis (P <0.05). The results show a significatively inhibition of the germinative index in the concentrations C1 (800 μl) and C3 (200 μl) by the active ingredient clethodim. For root growth, it was possible to observe a significant decrease at higher concentrations compared to the negative control. For cell cycle analysis, only C1 showed a significant increase in the frequency of micronuclei and for the phases of the cell cycle, with no statistical difference being observed between treatments. The analysis of oxidative stress showed that there was a significant increase in enzyme activity for CAT in the concentrations: C1 and C2 and APX in the concentrations: C1, C2 and C3, in comparison to the negative control. Analyzing the results, it was observed that the herbicide clethodim was phytotoxic for inhibiting the germination index, cytotoxic for decreasing root growth, genotoxic for increasing the occurrence of nuclear alterations, in addition to altering the enzymatic activity.
Keywords: Onion. Cytogenotoxicity. Oxidative stress. Herbicide. Mutagenesis
