Avaliação da germinação e crescimento inicial de espécies florestais arbóreas frente exposição a pesticidas
Date
2022-08-12Author
http://lattes.cnpq.br/8259420484216146
https://orcid.org/0000-0002-5307-7664
SANTOS JÚNIOR, Ivan Alves dos
Metadata
Show full item recordAbstract
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 organisms 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 exposed to concentrations of
cypermethrin, atrazine, glyphosate and 2,4-D pesticides in seed germination and in
the early growth phase. The concentrations used were ¼, ½, recommended average
concentration, 2x and 4x. 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 (CE50) values were estimated based on the percentage of test
organisms mortality. In test I, the average results for width, thickness and length of
seeds were observed, which were 7.48, 1.70 and 13.54 mm for H. petraeum and
4.31, 2.43 and 7.51 mm for E schomburgkii, respectively. The weight of 1000 seeds
was 155.79 g for H. petraeum and 64.6 g for E. schomburgkii. In assay I, the CE50
for H. petraeum was 2.34 mg/L for glyphosate and 1.49 mg/L for 2-4-D, while for E.
schomburgkii the CE50 was 6.38 mg/L to 2,4-D. In assay II, for H. petraeum and E.
schomburgkii the CE50s were respectively 26.72 and 9.66 mg/L for atrazine, 11.96
and 20.20 mg/L for glyphosate and 5.34 and 9.67 mg/L for 2.4D. The pesticide
concentration can affect non-target organisms such as Hymenolobium petraeum and
Enterolobium schomburgkiit delaying and inhibiting GSI and G (%) and, causing MF
(%) of organisms mainly affected by atrazine, glyphosate and more severely by 2,4-D
formulations. The test II showed that growth variables as plant dry material mass
were the most affected by pesticides concentration studied.