RESUMO
2-Phenylethynyl-Butyltellurium (PEBT) is a synthetic organotellurium compound that has shown various pharmacological properties on mammals without any signs of toxicity, but its effects on insects have not been reported before. Therefore, the aim of this study was to assess whether acute exposure to PEBT would promote an insecticidal effect against Drosophila melanogaster. The flies were exposed to three concentrations of PEBT (0.325 µmol L-1, 1.300 µmol L-1, and 5.200 µmol L-1) and a control solution (vehicle), using 450 flies per treatment (three repetitions of 150 flies), for 48 hours. Negative geotaxis and open field tests were performed (in vivo) after 24 and 48h, and acetylcholinesterase (AChE) activity was assessed (ex vivo) after 48h. Also, the mortality rate, 50% Lethal Concentration (LC50), 80% Lethal Concentration (LC80), and 95% Lethal Concentration (LC95) were calculated. Our results show that PEBT presented insecticidal activity against Drosophila melanogaster at all tested concentrations, which caused locomotor impairment and increased acetylcholinesterase activity in the flies' heads.
Assuntos
Inseticidas , Compostos Organometálicos , Animais , Drosophila melanogaster , Acetilcolinesterase , Inseticidas/farmacologia , Compostos Organometálicos/farmacologia , MamíferosRESUMO
ABSTRACT: Leaf area is an important growth variable in agricultural crops and the leaf is the main variable of interest in the tobacco industry. So, the aim of this scientific research was to estimate the Burley tobacco leaf area by linear dimensions of the leaves and to determine which mathematical model is more adequate for this purpose. Two experiments were carried out with Burley tobacco, cultivar DBH 2252, in 2016/2017 and 2018/2019 agricultural years, respectively, in the municipalities of Itaqui and Vanini - RS - Brazil. In 600 leaves were measured length (L), width (W), length×width product (LW), length/width ratio (L/W) and determined the real leaf area (LA). Four hundred and fifty leaves were separated to generate models of the leaf area as a function of linear dimension and the other 150 leaves were used for model's validation. The power model LA = 0.5037LW1.04435 (R² = 0.9960) is the most adequate for Burley tobacco 'DBH 2252' leaf area estimation. Alternatively, the models LA=2.0369W1.8619 (R²=0.9796) and LA=0.1222L2.2771 (R²=0.9738) based on width and length, respectively, can be used when only one leaf dimension is measured.
RESUMO: A área foliar é uma importante variável de crescimento em culturas agrícolas, sendo a folha a principal variável de interesse na indústria do tabaco. Assim, o objetivo deste estudo científico foi determinar a área foliar de tabaco tipo Burley por meio de dimensões lineares da folha e determinar qual modelo matemático é mais adequado para essa finalidade. Dois experimentos foram conduzidos com tabaco tipo Burley, cultivar DBH 2252, nos anos agrícolas de 2016/2017 e 2018/2019, respectivamente, nos municípios de Itaqui e Vanini, RS, Brasil. Em 600 folhas foram medidos o comprimento (L), a largura (W), o produto comprimento×largura (LW), a razão comprimento/largura (L/W) e determinada a área foliar real (LA). Foram separadas 450 folhas para a geração de modelos de estimativa de área foliar em função da dimensão linear e 150 folhas foram utilizadas para a validação dos modelos. O modelo LA = 0,5037LW1,04435 (R² = 0,9960) é adequado para a estimação da área foliar de tabaco Burley cultivar DBH 2252. Alternativamente, os modelos LA=2,0369W1,8619 (R²=0,9796) e LA=0,1222L2,2771 (R²=0,9738) baseados na largura e comprimento, respectivamente, podem ser utilizados quando apenas uma dimensão da folha é medida.
RESUMO
ABSTRACT: The objectives of this work were estimate the leaf area of squash 'Brasileirinha' by linear dimensions of the leaves and check models available in the literature. An experiment was conducted in the 2015/16 sowing season. Were collected 500 leaves and in each one, were measured the length (L), width (W) and length×width product (LW) and determined the real leaf area (LA). Then, 400 leaves were separated to generate models of the leaf area (LA) as a function of linear dimension (L, W or LW) of squash. The remaining 100 leaves were used for the validation of models. A second experiment was conducted in the 2016/17 sowing season. Were collected 250 leaves, used only for the validation of the models of the first experiment. There is collinearity between L and W and, therefore, models using the LW product are not recommended. The model LA=0.5482W2 + 0.0680W (R²=0.9867) is adequate for leaf area estimation of squash 'Brasileirinha'.
RESUMO: Os objetivos deste trabalho foram estimar a área foliar de abobrinha 'Brasileirinha' por dimensões lineares das folhas e testar modelos disponíveis na literatura. Foi conduzido um experimento na safra 2015/16 sendo coletas 500 folhas. Em cada folha foram mensurados comprimento (L), largura (W), calculado produto comprimento×largura (LW) e determinada a área foliar real (LA). Depois, 400 folhas foram separadas para a geração de modelos da área foliar real (LA) em função da dimensão linear (L, W ou LW) de abobrinha. As demais 100 folhas foram utilizadas na validação dos modelos. Um segundo experimento foi conduzido na safra 2016/17, no qual foram coletadas 250 folhas utilizadas na validação dos modelos gerados no primeiro experimento. Existe colinearidade entre L e W e, por isso, os modelos que utilizam o produto LW não são recomendados. O modelo LA=0,5482W2+0,0680W (R²=0,9867) é adequado para a estimação de área foliar de abobrinha 'Brasileirinha'.
