Banca de QUALIFICAÇÃO: ALANA CAVALCANTE DA SILVA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE: ALANA CAVALCANTE DA SILVA
DATA: 29/07/2022
HORA: 14:00
LOCAL: Google Meet - meet.google.com/tre-udjx-zqs
TÍTULO: Comparative study of sulfur-induced drought tolerance in cowpea plants grown in greenhouse and field conditions
PALAVRAS-CHAVES: plant defense; growth environment; plant nutrition; Vigna unguiculata; water deficit; water status.
PÁGINAS: 33
GRANDE ÁREA: Ciências Agrárias
ÁREA: Agronomia
SUBÁREA: Fitotecnia
ESPECIALIDADE: Fisiologia de Plantas Cultivadas
RESUMO:

Water deficit is an extremely limiting environmental condition for plants because it causes morphological, physiological, and biochemical changes in plants that result in severe losses in plant productivity. Our working hypothesis is that sulfur (S) supply effectively activates physiological defense mechanisms and increases tolerance to water deficit in cowpea plants under semiarid conditions. The experiments were conducted under two environmental conditions, in greenhouse and experimental field, with two cowpea genotypes (Xique-xique and Novaera) exposed to two water levels (control and drought) and three doses of S [40 (recommended), 80, and 120 kg ha^-1 S in soil]. After 21 days of stress in the greenhouse and 28 days in the field, growth parameters (leaf area, dry mass of leaves, stem, and shoot), leaf succulence, drought tolerance, relative water content, osmotic potential, leaf temperature, net photosynthesis, transpiration rate, stomatal conductance, and S content were measured. The data showed that plants responses varied to water restriction depending on growth conditions, being affected by S supply. In the greenhouse, the growth of cowpea plants was lower than that in the field, even under well-irrigated conditions. The phenomenon was more evident when the plants were exposed to water deficit, with drastic reductions in net photosynthesis, stomatal conductance, dry mass of leaves, stem, and shoot, and relative tolerance for both genotypes. A surprising result was that the stressed plants grown in the greenhouse had better control of water status. The results indicate that S supplementation plays an effective role in mitigating drought damage, reflecting the recovery of growth in a genotype known to be sensitive to water deficits, the Novaera one. The results indicate that the Novaera genotype is more responsive to S supplementation and that S accumulation in cowpea tissues varies with the growth environment, stress level, and soil S level. S supplementation improved the physiological performance of stressed Novaera plants by increasing relative water content (RWC) and partially recovering the rates of net photosynthesis, stomatal conductance and transpiration, a specific response to S levels in the greenhouse (dose S-80) and field (dose S-120). As a conclusion, our data clearly indicate that S supplementation mitigates the damage caused by water deficit in Novaera plants and emerge as a powerfully strategy to cultivate cowpea plants in water-scarce environments.

MEMBROS DA BANCA:
Presidente - 1342777 - RAFAEL DE SOUZA MIRANDA
Externo ao Programa - 1553560 - FRANCISCO DE ALCANTARA NETO
Externo à Instituição - JOSE HELIO COSTA - UFC