Respostas fisiológicas da soja à adubação potássica sob dois regimes hídricos

• Ano de defesa: 2012
• Autor(a) principal: Catuchi, Tiago Aranda
• Orientador(a): Souza, Gustavo Maia
• Banca de defesa: Santos, Ana Claudia Pacheco , Farias, José Renato Bouças
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade do Oeste Paulista
• Programa de Pós-Graduação: Mestrado em Agronomia
• Departamento: Ciências Agrárias
• País: BR
• Palavras-chave em Português: Fotossíntese. Biomassa; Deficiência hídrica; Nutrição; Glycine max
• Palavras-chave em Inglês: Photosynthesis; Biomass; Water stress; Nutrition; Glycine max
• Área do conhecimento CNPq: CNPQ::CIENCIAS AGRARIAS::AGRONOMIA
• Link de acesso: http://bdtd.unoeste.br:8080/tede/handle/tede/549

Water deficit is one of the main factors limiting agricultural production worldwide, affecting many physiological processes in plants. Based on this context, the study aimed to evaluate the interference of potassium fertilization on physiological responses of two soybean cultivars developed under water deficit, and assess the level of tolerance to water stress among cultivars. For this we tested the following hypotheses: 1) K supplementation in soybean plants grown under water deficiency can contribute to minimize the effects of water shortage on the physiology of the plant, 2) the difference in the level of tolerance to water stress between the cultivars depend directly from the application of K. The experiment was conducted in a greenhouse in 2x2x3 factorial design, ie, two soybean cultivars, water stress at 100% and 40% of the daily replacement of water compared to field capacity (CC), and three levels of supplementation with K which was held at planting. To test the assumptions above, we assessed the following parameters: leaf water potential index, chlorophyll content, membrane leakage, photosynthetic potential and biomass yield. Based on the results, we conclude that: Under conditions of water stress, the K fertilization did not interfere significantly in biomass and physiological parameters evaluated at work. Potassium supplementation promoted a better efficiency of physiological parameters in controlling water status in both cultivars, where the main variables were influenced by the nutrient to the stomatal conductance (gs), maximum rate of carboxylation of Rubisco (Vcmax) and maximum CO2 assimilation (Amax ). K supplementation improved the recovery of photosynthetic plants after rehydration, especially the cultivar Embrapa 48. With respect to the parameters of biomass in water status of control, the BR-16, potassium fertilization increased the production of total dry mass per plant and yield, as the cultivar Embrapa 48, only the latter parameter was influenced by biomass potassium.