Banca de QUALIFICAÇÃO: RITA DE CÁSSIA SILVA

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : RITA DE CÁSSIA SILVA
DATE: 26/04/2024
TIME: 08:30
LOCAL: Online
TITLE:

Light-dependent damage in the physiology of Amaranthus hybridus subjected to ammonium glufosinate application

KEY WORDS:

Photosynthesis, Glutamine synthetase, Lipid peroxidation, Reactive oxygen species

PAGES: 15
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Matologia
SUMMARY:

After the application of glufosinate in the field, its control over weeds can vary depending on environmental conditions such as light, temperature, and relative humidity. The outcome of control may differ when applied to young leaves compared to old leaves, due to variations in environmental conditions. In this study, we aimed to evaluate the physiology of both young and old leaves of Amaranthus hybridus in response to glufosinate sprayed under different light conditions. Symptoms of phytotoxicity developed more intensely in Amaranthus hybridus plants when exposed to light during glufosinate application (504 g a.i. ha-1), particularly affecting the old leaves. The herbicide glufosinate ammonium inhibited the photosynthetic activity of Amaranthus hybridus. This inhibition of photosynthesis resulted in an increase in fluorescence emission, culminating in its disruption 24 hours after application only in the old leaves exposed to sunlight. In contrast, application in the dark showed an increase in fluorescence emission 12 hours after application when subsequently exposed to light. The accumulation of superoxide and hydrogen peroxide was light-dependent, leading to subsequent MDA accumulation. Antioxidant enzymes may not provide antioxidant protection against oxidative damage caused by glufosinate. Light conditions interfered with GST activity. Consequently, glufosinate ammonium relies on photosynthesis, indirectly affecting the electron transport flow in PSII to generate ROS.

COMMITTEE MEMBERS:
Interno - 1905333 - AROLDO FERREIRA LOPES MACHADO
Interna - 2466219 - CAMILA FERREIRA DE PINHO
Externa à Instituição - CRISTINA MOLL HUTHER - UFF
Externa à Instituição - NATÁLIA DA SILVA GARCIA - UFRRJ