Banca de DEFESA: LEIDY ALVES DOS SANTOS

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : LEIDY ALVES DOS SANTOS
DATA : 30/04/2021
HORA: 15:00
LOCAL: meet.google.com/yhm-zsxg-eys
TÍTULO:

Brassinosteroids systemically trigger tolerance to magnesium stress in soybean plants

PALAVRAS-CHAVES:

Oxidative stress, 24-epibrassinolideo, Plant anatomy, Photosynthetic characteristics

PÁGINAS: 74
RESUMO:

The general objective of this study was to evaluate whether the foliar application of 24- epibrassinolide (EBR) can mitigate oxidative stress in soybean plants submitted to high and low addition of Mg and to evaluate its possible repercussions on anatomical, nutritional, biochemical, physiological and morphological behaviors. For this, the experiment followed a completely randomized factorial design with two concentrations of 24-Epibrassinolide (0 and 100 nM EBR, described as - EBR and + EBR, respectively) and three Mg supplies (0.0225, 2.25 and 225 mM Mg, described as low, control and high Mg supply). In general, low and high Mg supplies promoted deleterious effects on antioxidant metabolism, photosynthetic pigments and negative changes in the anatomical parameters evaluated. However, in treatments with low and high Mg + EBR, increases in the thickness of the epidermis of the root, endoderm, cortex, vascular cylinder and metaxylem were observed. Likewise, EBR promoted increases in stomata density, leaf epidermis thickness, palisade and spongy parenchyma thickness, confirming the action of EBR on cell division and tissue differentiation. Plants exposed to low and high Mg and sprayed with EBR showed improvements in the accumulation of Mg and content of macronutrients (K, Ca, S) and micronutrients (Mn, Cu and Bo) suggesting that this steroid improved the absorption, transport and accumulation of nutrients in the evaluated tissues. The EBR promoted increases in the activities of antioxidant enzymes in plants under Mg stress, revealing the beneficial effect of mitigating oxidative damage to chloroplast photosystems and membranes. Allied to this, the EBR mitigated the negative impacts induced by the low and high concentration of Mg in the liquid photosynthesis rate and instant carboxylation associated with the increments obtained in the electron transport rate and stomatal density. We conclude that EBR reduced oxidative stress caused by low and high addition of Mg with positive repercussions on antioxidant enzymes, photosynthetic pigments and root and leaf biomass.

MEMBROS DA BANCA:
Presidente - 1803899 - ALLAN KLYNGER DA SILVA LOBATO
Interno - 2874082 - GILSON SERGIO BASTOS DE MATOS
Externa à Instituição - ANA CARLA FEIO DOS SANTOS - MPEG
Externo à Instituição - BRENO RICARDO SERRÃO DA SILVA - ITV
Externo à Instituição - FLÁVIO JOSÉ RODRIGUES CRUZ - UFRPE