Ação de reguladores de crescimento e temperatura em variedades de taioba

• Autor(a) principal: Souza, Cristina Soares de
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/1342
• topic: Xanthosoma sagittifolium; Taioba; Armazenamento refrigerado; Reguladores de crescimento; Injúria por frio; Carboidratos; Enzimas oxidativas; Xanthosoma sagittifolium; Taioba; Cold storage; Growth regulators; Injury by cold; Carbohydrates; Oxidative enzymes; CNPQ::CIENCIAS AGRARIAS::AGRONOMIA::FITOTECNIA::MELHORAMENTO VEGETAL

The goals of this work were to evaluate the effect of cold temperature and length of storage on the plant growth of tannia in the greenhouse; evaluate the influence of growth regulators and carving on the rhizomes sprouting and growth of tannia; verify the effect of cold temperature and length of cold storage, as well as the application of cytokinin and ethylene, in carved rhizomes, on the development of lateral sprouts and cold tolerance of tannia genotypes; evaluate the cold tolerance of tannia cultivars and the relation of this response with enzyme activity, accumulation of phenolic compounds and postharvest metabolism of carbohydrates. The storage for 7 days at 10 ºC before the transplanting was sufficient to determine higher growth of lateral sprouts. The cold pretreatment for 7 days promoted higher plant growth, and exposition of 14 days had a larger effect over the aerial part growth. The storage at 10 ºC was efficient in expanding the leaf area in tannia plants, especially if prolonged for 14 days. The production of new leaves and expansion of leaf area were stimulated by treating the rhizomes with 500 mg L-1 BAP and 250 mg L-1 BAP + 250 mg L-1 Ethrel. Regardless the use of the carving induced higher number of new sprouted leaves, 35 days after planting. Sprouting was anticipated when the carved rhizomes were treated with 250 mg L-1 BAP + 250 mg L-1 Ethrel. Cold storage (5 ºC for 3 months, and 10 ºC for 6 months) caused chilling injury in tannia rhizomes. The browning of the rhizomes may be associated with increased peroxidase and polyphenoloxidase activity, stimulated by the cold. The susceptibility to stress conditions was dependent of the tannia genotype. The storage for 20 days at 5 and 10 ºC didn t induce changes in the contents of soluble sugars and reducing sugars, but induced the degradation of starch in leaves of tannia. The cold didn t stimulate peroxidase and polyphenoloxidase activity in leaves for consumption. Tannia leaves were insensitive to cold temperatures, without sign of browning caused by the cold. Longer conservation of leaves was acquired in storage at 5 ºC.