Banca de QUALIFICAÇÃO: JONATAS VIEIRA SANTOS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JONATAS VIEIRA SANTOS
DATE: 20/12/2021
TIME: 14:00
LOCAL: Campus de Engenharias e Ciências Agrárias
TITLE:

EFFECT OF EXOGENOUS APPLICATION OF 24-EPIBRASINOLIDE ON
PHYSIOLOGICAL MECHANISMS AND ANTIOXIDANT DEFENSE IN WATER
DEFICIENT SUGARCANE

KEY WORDS:

Water stress. Brassinosteroid. Saccharum spp.. photosystem II. oxidative stress.
Chlorophylls.

PAGES: 59
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Fisiologia de Plantas Cultivadas
SUMMARY:

Sugarcane is a crop of great economic importance, used in the production of food, ethanol and
energy. Water deficit is one of the main factors that limit the productivity of this crop
worldwide. A new strategy in the agricultural scenario has been gaining emphasis to minimize
the effects of abiotic stresses on cultivated plants, through the exogenous application of plant
growth regulators, such as brassinosteroid, a 24-Epibrassinolide analogue. Therefore, the
objective of this work was to evaluate the exogenous action of 24-epibrassinolide in the
physiological mechanisms and antioxidant defense in sugarcane under water deficit in the
vegetative phase. The experiment was carried out at the Campus of Engineering and
Agricultural Sciences of the Federal University of Alagoas, Rio Largo, Alagoas, in a
greenhouse. The sugarcane cultivar RB92579 was used. The study comprised the combination
of factors concentrations of the hormone 24-Epibrassinolide (24-EpiBL, 0; 0.25; 0.50; 0.75;
1.00 and 1.25 mg L-1) and water regimen (RH) , according to water available (AW): control
(100-80% AW) and water stress (30-10% AW). The design was a randomized blocks, in a 6 x
2 factorial arrangement with five replications, totaling 60 plots. The hormone was applied in
five periods, within a fourteen-day interval, starting 74 days after planting (DAP) with the
imposition of the water regime. Physiological and biochemical analyzes were carried out
seven days after the last application. Water deficit caused reductions in the physiological and
biochemical activities of the plants, but after the applications of intermediate doses of 0.5 and
0.75 mg L -1 , it managed to attenuate the data caused by stress, through better leaf water status,
greater accumulation of photosynthetic pigments, effective quantum efficiency of
photosystem II (ΦPSII), gas exchange performance, enzymatic activity and

BANKING MEMBERS:
Interno - 1916144 - GILBERTO COSTA JUSTINO
Externo ao Programa - 1181648 - JOSE VIEIRA SILVA