Banca de QUALIFICAÇÃO: JULIANY MAYRA TEIXEIRA DE MOURA BARROS

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : JULIANY MAYRA TEIXEIRA DE MOURA BARROS
DATE: 04/04/2022
TIME: 14:00
LOCAL: Campus de Engenharias e Ciências Agrárias
TITLE:

Foliar application of 24-Epibrassinolide in the mitigation of water stress in soybean plants in the flowering stadium.

KEY WORDS:

: Glycine max. Drought. Brassinosteroids. Photosystem II. Chlorophylls.   

Biomass.

PAGES: 61
BIG AREA: Ciências Agrárias
AREA: Agronomia
SUBÁREA: Fitotecnia
SPECIALTY: Fisiologia de Plantas Cultivadas
SUMMARY:

Soybean is the most cultivated oilseed in the world, with multiple uses, from human and animal food products, as well as in the biofuels industry. Drought is one of the main abiotic stresses limiting the productivity of this crop in the world. To increase drought tolerance, 24-epibrassinolide (EBL) foliar application has been used in different crops, however, studies are still scarce in soybean crop in the flowering stage. Therefore, this work aims to evaluate the efficiency of the bioregulator (EBL) on the growth and physiological mechanisms in soybean in the flowering phase under water deficit and rehydration. The experiment was carried out in a greenhouse using the cultivar IMA 84114RR. The experimental design used was completely randomized blocks, in a 2x2 factorial scheme (Water regimes x Application with EBL) with seven replications. The water regimes, irrigated plants and under water stress followed by rehydration, were imposed when the soybean plants were in the flowering stage and after pre-treatment with EBL. During the experiment, morphological, physiological, productivity and biochemical analyzes were performed. EBL mitigated the effect of water stress on shoot growth of soybean plants, which after water stress followed by rehydration showed better recovery in plant height, leaf number and stem diameter compared to plants without EBL, it was not observed EBL effect for leaf area. EBL contributed to the greater production of leaf and stem dry mass of plants, but EBL did not improve soybean yield. In irrigated plants, EBL promoted better metabolic processes such as gas exchange, photosynthesis efficiency and chlorophyll synthesis, which must have contributed to the increase in biomass in the area. Plants treated with EBL under water deficit showed reduced stomatal conductance and photosynthesis similar to those without EBL. Plants with EBL showed an increase in transpiration and internal CO2 concentration under stress. The maximum quantum efficiency of photosystem II (Fv/Fm) did not change in plants with and without EBL regardless of stress. Foliar application of EBL on soybeans in the flowering stage alleviated the damage caused by water deficit, a fact evidenced by the reduction of physiological damage such as relative water content, leaf water potential, effective quantum efficiency of photosystem II (ΦPSII) and total chlorophyll. Thus, EBL partially alleviated the harmful effect of water stress on soybean in the flowering phase.

BANKING MEMBERS:
Interno - 1425368 - JOAO CORREIA DE ARAUJO NETO
Externa à Instituição - CLAUDIANA MOURA DOS SANTOS - IFAL
Externo à Instituição - SEBASTIAO DE OLIVEIRA MAIA JUNIOR