Banca de DEFESA: PAULO CÉSAR DE SOUZA JÚNIOR

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE: PAULO CÉSAR DE SOUZA JÚNIOR
DATA: 14/11/2025
HORA: 14:00
LOCAL: On line - Link da videochamada: https://meet.google.com/iqg-acvz-rds
TÍTULO:

Deciphering How Biostimulants Mitigate the Effects of Water Stress in Maize Plants

PALAVRAS-CHAVES:

Abiotic stress; Ascophyllum nodosum; Foliar fertilizer, photosyntesis, Zea mayz L.

PÁGINAS: 69
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

Climate change intensifies the risks to agricultural production, creating uncertainty for global food security. Developing sustainable strategies to mitigate water deficit is crucial, particularly for maize, a crop of major socioeconomic relevance in Brazil and worldwide. This study aimed to evaluate the effects of a multinutrient biofertilizer combined with seaweed extract on maize performance under water deficit. Three experiments were carried out: (i) a field trial in Vera, Mato Grosso do Sul; (ii) evaluations in 37 commercial production areas under field conditions; and (iii) a greenhouse trial conducted at the Department of Plant Physiology, Federal University of Lavras (Lavras, Minas Gerais, Brazil), arranged in a completely randomized design (CRD) with a 2 × 4 factorial scheme and five replicates. The first factor consisted of two water regimes: 100% (well-watered, WW) and 60% (deficit, WD) replacement of soil water-holding capacity (WHC), based on daily evapotranspiration. The second factor comprised four concentrations of the multinutrient biofertilizer plus seaweed extract (0, 0.5, 1.0, and 1.5 mL L⁻¹ of the commercial product YaraAmplix® BIOTRAC), totaling eight treatments and 40 experimental units. Evaluations were performed at three stages: maximum stress, rehydration, and final harvest. Measured variables included plant height, leaf number, stem diameter, net photosynthetic rate (A), stomatal conductance (gs), photosystem II efficiency (Fv/Fm), antioxidant enzyme activity, leaf water potential (pre-dawn and midday), chlorophyll a and b contents, leaf (LDM), stem (SDM), root (RDM), and total dry mass (TDM), as well as ear mass, ear length, 100-grain weight, and total grain yield per plant. The results revealed that low doses of the multinutrient biofertilizer plus seaweed extract promoted significant physiological and biochemical improvements in maize plants under severe water deficit, enhancing recovery after rehydration. Increases in plant water status, photosynthetic performance (A, gs), activation of the antioxidant system, and yield components were observed. Overall, the findings demonstrate that foliar application of a multinutrient biofertilizer enriched with seaweed extract represents a promising strategy to mitigate water stress effects in maize cultivation.

MEMBROS DA BANCA:
Externo à Instituição - ATILA FRANCISCO MOGOR - UFPR (Membro)
Interno - FERNANDA CARLOTA NERY - UFSJ (Membro)
Externo à Instituição - FERNANDO CESAR BACHIEGA ZAMBROSI - IAC (Suplente)
Presidente - PAULO EDUARDO RIBEIRO MARCHIORI (Membro)
Interno - VITOR DE LAIA NASCIMENTO (Suplente)
Externo à Instituição - VÍTOR GABRIEL AMBROSINI - YARA CNRD (Membro)
Interno - WILLIAN RODRIGUES MACEDO - UFSC (Membro)