Name: Kalia Dável Grecco
Type: MSc dissertation
Publication date: 19/02/2020
Advisor:
Name |
Role |
|---|---|
| Silvia Tamie Matsumoto | Advisor * |
Examining board:
| Name |
Role |
|---|---|
| Camilla Rozindo Dias Milanez | Internal Alternate * |
| IAN DRUMOND DUARTE | External Examiner * |
| Maria do Carmo Pimentel Batitucci | Internal Examiner * |
| Milene Miranda Praça Fontes | External Alternate * |
| Silvia Tamie Matsumoto | Advisor * |
Summary: Fungicides are pesticides often used in agriculture because of their action against fungal diseases. However, the widespread application of pesticides worldwide raises environmental and public health concerns as these compounds are toxic and may pose risks to ecosystems and human health. The present work aimed to evaluate the phytotoxic, cytogenotoxic, biochemical and physiological potential of azoxystrobin (AZO) and carbendazim (CARB) fungicides in Lactuca sativa L. and Phaseolus vulgaris L. Phytotoxicity was evaluated by germination and root growth analyzes, cytogenotoxicity by cell cycle analysis and chromosomal and nuclear alterations of L. sativa; the biochemical effects by analyzing the activity of antioxidant enzymes catalase, ascorbate peroxidase and superoxide dismutase, and the quantification of reduced glutathione in L. sativa; and the physiological effects by chlorophyll content and chlorophyll a fluorescence analysis in P. vulgaris. Six concentrations of each fungicide were used, based on the concentration recommended by the manufacturer, two concentrations above, and three
concentrations below the recommended, for AZO: C1: 0,56; C2: 0,28; C3: 0,14; C4: 0,07; C5: 0,035; C6: 0,0175 g/L, and for CARB: C1: 2,0; C2: 1,0; C3: 0,5; C4: 0,25; C5: 0,125; C6: 0,0625 mL/L. The positive control was trifluralin (0.84 g/L) and the negative control distilled water. The means were submitted to analysis of variance and compared by Tukey and Kruskal Wallis tests (p <0.05). The results showed that C1; C2; C3; C4 from AZO and C1; C2 from CARB reduced root growth; C1; C2 from AZO and C1; C2; C3 from CARB altered the mitotic index; and the C1 concentration of both fungicides increased the frequency of chromosomal alterations in L. sativa. Both fungicides induced the formation of chromosomal alterations such as chromosome bridges and chromosomal adhesions, and carbendazim also induced chromosomal losses at the highest concentrations tested. Oxidative stress analysis in L. sativa showed that the catalase enzyme showed an increase concentrations C1; C2; C3; C4 for AZO, and C1, C2; C3 for CARB; ascorbate peroxidase increased in C1 for AZO and in C1; C2 for CARB; and superoxide dismutase increased in C1; C2; C3 for both fungicides, while the quantification of reduced glutathione showed significant difference in all CARB concentrations and in C1, C2, C3, C4; C5 from AZO. In addition, C2, C3 and C4 concentrations of fungicides affected the energy absorption by P. vulgaris photosystem II. Given the tests performed, it was observed that the fungicides AZO and CARB were cytotoxic for decreasing root growth and mitotic index, cytogenotoxic for increasing the occurrence of chromosomal alterations, altered the enzymatic activity and energy absorption of plants used as test system.
