Relação da tolerância ao déficit hídrico com o teor e acúmulo de nitrogênio, fósforo e potássio em cultivares de cana-de-açúcar

• Autor(a) principal: Silva, Thais Ramos da [UNESP]
• Data de Publicação: 2015
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Repositório Institucional da UNESP
• Texto Completo: http://hdl.handle.net/11449/126611
• topic: Cana-de-açúcar; Nutrientes; Plantas - Efeito da umidade do solo; Irrigação com déficit hídrico; Plantas cultivares

In regions where expansion of sugarcane in Brazil will occur in the coming years an increase in the occurrence of extreme events such as the driest years. It then becomes important to the use of varieties tolerant to water stress in these new areas. The present study aimed to define the degree of tolerance to drought of three varieties of sugarcane by means of physiological variables and the relation of tolerance of these varieties with the content and accumulation of N, P and K. The experiment was conducted in pots containing a 50 dm3 Typic Haplustox. The experimental design was randomized blocks, with nine treatments (3 varieties x 3 water potential of the soil) with four replications. With 60 days of age the SP81-3250 varieties, RB855453 and IACSP95-5000 were submitted to the three soil water potential: Ψno restriction (-0.010 to -0.015 MPa), Ψmoderate (-0.050 to -0.055 MPa) and Ψsevere (-0.075 to -0.080 MPa) and evaluated at three times: 30, 60 and 90 days after treatment imposition. The variables analyzed were: number of green leaves, leaf area, plant height, number of tillers, leaf water potential, SPAD index, photosynthesis, transpiration, stomatal conductance, internal CO2 concentration, instantaneous carboxylation efficiency, instant use efficiency water, intrinsic water use efficiency, phytomass, N in the leaves, N in the stalks, N accumulation, P in the leaves, P in the stalks, P accumulation, K in the leaves, K in the stalks, K accumulation and N, P and K utilization efficiency. There were lower values in plants of the varieties Ψsevere compared to plants under Ψno restriction the variables: number of green leaves, leaf area, plant height, number of tillers, SPAD index, photosynthesis, transpiration, stomatal conductance, instant efficiency carboxylation, intrinsic efficiency of water use, instantaneous water use efficiency, phytomass, N, P and K in the leaves ...