Banca de DEFESA: IVAN ALVES DOS SANTOS JÚNIOR

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : IVAN ALVES DOS SANTOS JÚNIOR
DATE: 12/08/2022
TIME: 14:30
LOCAL: video conferência
TITLE:

EVALUATION OF GERMINATION AND INITIAL GROWTH OF TREE FOREST SPECIES IN FRONT OF PESTICIDES EXPOSURERE

KEY WORDS:

forest species; chemical substances. ecotoxicological tests

PAGES: 79
BIG AREA: Ciências Biológicas
AREA: Ecologia
SUBÁREA: Ecologia Aplicada
SUMMARY:

The use of pesticides is advancing fastly in the world, partly, justified by population growth. However, these substances are often used indiscriminately, above the recommended doses, leading to ground contamination, surface and groundwater, and consequently, the environment damage, affecting non-target organisms. It is possible to estimate the harmful effects of pesticides on environmental quality using ecotoxicology support, which is an area of study that uses different methodologies through bioassays with organisms sensitive tests to the toxic substance effect tested. The aim of this study is to verify the response of botanical species Hymenolobium petraeum Ducke and Enterolobium schomburgkii Benth involved into cypermethrin, atrazine, glyphosate and 2,4-D pesticides in seed germination and in the early growth phase. The seeds were collected and submitted to pre-experiment treatment of disinfection and chemical scarification. The study was developed in a controlled environment and divided into two stages: test I - morphometric evaluation and seeds exhibition to different pesticides concentration, where the germination speed index - GSI, germination percentage - G (%) and final mortality - FM (%) of seeds were evaluated; and test II - evaluation of variables in seedlings during 30 days exhibiting to pesticide concentration, where stem length -SL, root length -RL, collar diameter - CD, air part dry material mass – APDM, root dry material mass – RDM, total dry material mass – TDM were estimated. In addition, the mean effective concentration (EC50) values were estimated based on the percentage of test organisms mortality. The average results for width, thickness and for seeds length were 7.48, 1.70 and 13.54 mm for H. petraeum and 4.31, 2.43 and 7.51 mm for E. schomburgkii. The 1000 seeds weight was 155.79 g for H. petraeum and 64.6 g for E. schomburgkii. EC50s were estimated for glyphosate formulations at 2.34 mg/L and for 2,4-D at 1.49 mg/L on species H. petraeum, while for E. schomburgkii only 2,4-D standed for estimate at concentration 6.38 mg/l. The test II estimated the EC50 for atrazine,  glyphosate and 2,4-D formulations in both test organisms, where for H.petraeum species, the atrazine estimated a concentration of 26.72 mg/L, glyphosate of 11.96 mg/L. L and 5.34 mg/L 2,4-D; for E. schomburgkii, the atrazine estimated a concentration of 9.66mg/L, glyphosate of 20.20 mg/L and 2.4D of 9.67 mg/L. The pesticide concentration can affect non-target organisms such as Hymenolobium petraeum and Enterolobium schomburgkii. The results for test I showed that pesticide concentration inhibit GSI and G (%) of plants and that FM (%) was mainly affected by atrazine, glyphosate and more severely by 2,4-D formulations. The test II showed that markers of effects related to growth such as plant dry material mass were the most affected by pesticides concentration studied. Furthermore, ecotoxicological studies are needed in order to understand the magnitude of these effects on ecology and the dispersion of these organisms.

BANKING MEMBERS:
Presidente - 1836832 - RUY BESSA LOPES
Interno - 1562643 - MAXWELL BARBOSA DE SANTANA
Externo ao Programa - 1549200 - LUCINEWTON SILVA DE MOURA