Banca de DEFESA: MARCIO YUKIHIRO KOHATSU

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : MARCIO YUKIHIRO KOHATSU
DATA : 07/06/2021
HORA: 14:00
LOCAL: WEBCONFERÊNCIA
TÍTULO:

Effects of biogenic copper oxide nanoparticles in in vitro and in vivo bioassays with lettuce (Lactuca sativa L.)

PÁGINAS: 110
GRANDE ÁREA: Ciências Agrárias
ÁREA: Ciência e Tecnologia de Alimentos
SUBÁREA: Ciência de Alimentos
ESPECIALIDADE: Toxicidade e Resíduos de Pesticidas em Alimentos
RESUMO:

Copper oxide nanoparticles (CuO NPs) have been used in agriculture as fertilizers, pesticides, herbicides and insecticides, which has contributed to the increase in agricultural production. However, NPs can cause several phytotoxic effects, which depend on the dose, synthesis, size, composition and sensitivity of the seed / plant. Thus, it is extremely important to evaluate the safe conditions for the application of NPs in agricultural use. Considering this context, the present study aimed to evaluate and compare the effects of applying different concentrations (0 to 300 mg L^-1) of biogenic CuO NPs synthesized with green tea extract (Camellia sinensis) on lettuce (Lactuca sativa L.) by in vitro (Petri dishes), with n = 6, and in vivo (cultivable soil) bioassays, with n = 4. For the in vivo bioassay, CuSO₄ was used for comparison with the NPs and two application routes were tested (leaf and irrigation in the ground). Elongation and oxidative stress (enzymatic and total antioxidant activity) in lettuce seed roots were evaluated in in vitro bioassays. In the in vivo bioassays, in addition to the assessment of oxidative stress, the concentrations of macro and microelements present in lettuce and soil, the pigments (chlorophyll [a,b] and carotenoids) and secondary metabolites (phenolic compounds and total flavonoids) were determined. The data were analyzed using Analysis of Variance (ANOVA) one-way (in vitro bioassays) and two-way (in vivo bioassays), Pearson's correlation (in vitro and in vivo bioassays) and exponential regression (in vitro bioassays). The application of concentrations ≤ 40 mg L^-1 of CuO NPs improved seed germination in in vitro bioassays. In addition, there was less production of nitric oxide signaling species (nitrite and R-S-nitrosothiols); at concentrations ≥ 80 mg L^-1, root growth was reduced by 35 to 75%. With the increase in CuO NPs concentrations, the levels of nitric oxide signaling species in the rootlets increased. However, the total antioxidant activity, catalase, peroxidase and ascorbate peroxidase (APX) showed no significant difference (p <0.05) and there was a reduction in the enzyme superoxide dismutase (SOD). In relation to the results of in vivo tests, the parameters of productivity (dry mass and number of leaves) of lettuce for leaf exposure of CuO NPs (FNP) increased significantly. There was an increase in the concentration of several nutrients (K, Na, S, Cu and Zn) and the estimates of daily intake (EID) are in accordance with the reference dietary intake (CDR) for FNP. Regarding the elements potentially toxic to humans, according to the limits of provisional tolerable daily intake (IDTP), these values represent a maximum of 3.33% of the IDTP of the elements for the FNP group. Photosynthetic pigments were not reduced and APX was reduced. Compared with salt treatments, there was an increase in APX enzyme activity, a reduction in RSNOs, chlorophyll b and carotenoids. Thus, the study represents advances in understanding the effects of leaf application of CuO NPs on the absorption of micronutrients with great potential for agricultural applications.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 1809833 - TATIANE ARAUJO DE JESUS
Membro Titular - Examinador(a) Interno ao Programa - 3047358 - RICARDO HIDEO TANIWAKI
Membro Titular - Examinador(a) Externo ao Programa - 206.339.958-19 - LEONARDO FERNANDES FRACETO - UNICAMP
Membro Suplente - Examinador(a) Interno ao Programa - 1814655 - LUCIA HELENA GOMES COELHO
Membro Suplente - Examinador(a) Externo ao Programa - 839.822.640-49 - RODRIGO MENDES PEREIRA - UFABC