Banca de DEFESA: JÉSSICA FERREIRA LOURENÇO LEAL

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JÉSSICA FERREIRA LOURENÇO LEAL
DATE: 24/06/2022
TIME: 13:00
LOCAL: Webconferência
TITLE:

Physiological and Metabolism Responses of Conyza sumatrensis to Herbicides

KEY WORDS:

Multiple resistance. Genetic inheritance. Chlorophyll Fluorescence. Multiple Resistence

PAGES: 137
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

The Conyza spp. has been causing major problems in the agricultural production system, mainly due to cases of multiple resistance to herbicides. The objective of the work is to characterize the resistance systems of Conyza sumatrensis to herbicides, and to understand the physiological behavior of the species under herbicide application. The objective of the study was to evaluate a dynamic of the dissipation of photosynthetic energy of Conyza spp. through the application of PSII-inhibiting and FSI-inhibiting herbicides (Chapter I). To evaluate the rapid metabolic and physiological responses, mediated by oxidative stress, induced by time, in C.sumatrensis resistant and susceptible to the herbicide 2,4-D under natural conditions, conditions, temperature and light variations (Chapter II). Propose new chemical management alternatives for the biotype of C. sumatrensis with multiple resistance to the herbicides 2,4-D, glyphosate, diuron, paraquat and saflufenacil (Chapter III). Understand the cross-resistance to C. sumatrensis PSI-inhibiting herbicides (paraquat and diquat) and their physiological response to paraquat application (Chapter IV). The previous results describe that decreases in the photosynthetic performance index in C. sumatrensis treated with metribuzin and paraquat even without visual damage of growth and development clearly demonstrate the potential of using chlorophyll fluorescence to quickly track how metabolic disturbances in the C. sumatrensis under herbicide application metribuzin and paraquat (Chapter I). The C. sumatrensis 2,4-D–resistant biotype showed rapid photosynthetic damage after 2,4-D treatment compared with the susceptible biotype. The antioxidant enzyme activities were higher in the resistant biotype. Temperature effects appeared to modulate the speed of initiation of the rapid necrosis process. The symptoms occurred faster in the 2,4-D–resistant biotype under higher temperatures. Production of H2O2 in the 2,4-D–resistant biotype was not light dependent. In addition, basal antioxidant enzyme activity is higher in the resistant biotype. (Chapter II). The results obtained that the biotype of C. sumatrensis with multiple resistance to the herbicides 2,4-D, paraquat, saflufenacil, glyphosate and diuron can also show resistance to the herbicides inhibitors ALS chlorimuron-ethyl, imazapique + imazapyr and ethoxysulfuron. Studies will be developed to confirm the hypothesis (Chapter III). Cross resistance to diquat was detected in the paraquat resistant C. sumatrensis biotype. The paraquat-resistant biotype does not induce antioxidant enzymes, as a possible mechanism of resistance to paraquat, but shows rapid recovery of photosynthetic parameters and continuous growth when subjected to paraquat, while the susceptible biotype does not survive the application of the herbicidal paraquat (Chapter IV). The paraquat resistance in F2 and F3 was based on a single-dominant gene model (3:1), while the diquat results was based on two genes segregated independently (15:1) in Conyza sumatrensis (Chapter V).

BANKING MEMBERS:
Presidente - 2466219 - CAMILA FERREIRA DE PINHO
Interno - 1712769 - PEDRO CORREA DAMASCENO JUNIOR
Externo à Instituição - GILIARDI DALAZEN - UEL
Externo à Instituição - JUNIOR BORELLA - FURG
Externo à Instituição - RUBEM SILVÉRIO DE OLIVEIRA JUNIOR