Crescimento e produção de hastes florais de gladíolo cultivado sob diferentes tensões de água no solo

Abstract

RESUMOAs plantas ornamentais, em geral, e o gladíolo, em particular, são bastante suscetíveis às variações do nível de água no solo. No presente estudo foram avaliados os efeitos de diferentes níveis de tensão de água no solo sobre o crescimento e produção do gladíolo, em experimento realizado em casa-de-vegetação em Lavras, Minas Gerais. Esses efeitos foram caracterizados nas fases de crescimento vegetativo, espigamento e floração, por análises das seguintes medidas de crescimento: altura da planta, tamanho da haste floral e número de flores. O delineamento experimental foi o inteiramente casualizado em esquema de faixas, avaliando-se quatro níveis de tensão de água no solo (15, 25, 40 e 60 kPa) em cada uma das três fases fenológicas da cultura, totalizando doze tratamentos e seis repetições. Os resultados mostraram que a altura da planta, tamanho da haste floral e o número de flores foram significativamente reduzidos pelo aumento dos níveis de tensão de água no solo, sendo os efeitos mais intensos nas fases de crescimento e espigamento. Os melhores resultados em relação ao tamanho da planta, da haste floral e número de flores, foram obtidos mantendo-se a tensão de água no solo próxima à capacidade de campo.Termos para indexação: Gladiolus x grandiflorus, irrigação, análise de crescimento. ABSTRACTThe ornamental plants in general, and specially the gladiolus, are susceptible to variations of the soil water level. The effects of different soil water tensions on growth and production of gladiolus were evaluated in an experiment carried out in a greenhouse located in Lavras, Minas Gerais State, Brazil. These effects were characterized during the stages of vegetative growth, pre-flowering and flowering by analyzing plant height, floral stem length and number of flowers. The experimental design was completely randomized in a strip outline of four levels of soil water tensions (15, 25, 40 and 60 kPa) on each growth stage, totalizing twelve treatments and six replications. The results demonstrated that plant height, floral stem length and number of flowers were reduced by increasing the levels of soil water tension with higher effects during the stages of vegetative growth and pre-flowering. The best results in terms of plant size, length of the floral stem and number of flowers were obtained maintaining the level of soil water tension close to the field capacity. Index terms: Gladiolus x grandiflorus, irrigation, growth analysis. (Recebido em 20 de setembro de 2005 e aprovado em 24 de março de 2006)1 Parte da tese de doutorado desenvolvida pela primeira autora. 2 Engenheira Agrícola, Doutora em Irrigação e Drenagem -Unidade de Gestão da Educação Presencial/GEDUP, Engenharia de Produção -Centro Universitário do Sul de Minas/UNIS -Av. Coronel José Alves, 256, Bairro Vila Pinto -37010-540 -Varginha, MG -jodurao@oi.com. 3 Engenheiro Agrícola, Doutor -Engenharia -Universidade Federal de Lavras/UFLA -Cx. P. 3037 -37200-000 -Lavras, MG -jacintoc@ufla.br 4 Engenheira Agrônoma, Doutora -Agricultura -Universidade Federal de La...

Management of corm size and soil water content for gladiolus flower production

“…Overall, the treatment of 25% FC presented the lowest results for the vegetative part (Figure 2), corroborating with Pereira et al (2009), who reported that gladiolus plants are very sensitive to water deficit, showing poor growth and flowering when submitted to these conditions. In addition, Wright and Burge (2000) observed that symptoms of water stress include lower growth, what is much apparent in this study.…”

“…The treatment of 125% FC, which promoted the longest period from planting to harvest (86.2 days), should be disregarded once as longer plants remain under cultivation as more expensive becomes their production for the grower. With respect to number of decayed corms, according to Pereira et al (2009), water excess favors rot besides inducing plant cycle delay, what we also found. However, 25% FC also promoted an equal number of decayed corms.…”

“…In addition, Wright and Burge (2000) observed that symptoms of water stress include lower growth, what is much apparent in this study. Furthermore, Shillo and Halevy (1976b), Bastug et al (2006), andPereira et al (2009) mentioned that gladiolus vegetative development and flower stem initial growth are the most sensitive stages to soil water shortage. In fact, water deficit permanently affected plant development as, although plants remained alive, such treatment did not promote any flowering, as also reported by Shillo and Halevy (1976a) for gladioli cultivated under low soil moisture.…”

“…Positive results obtained for the vegetative parts of plants cultivated under 81% FC, therefore, directly influenced development of reproductive parts. According to Pereira et al (2009), gladiolus flowering is directly affected by an either vigorous or poor vegetative growth.…”

“…Although gladiolus plants are not soil-specific, they should not be cultivated in clayey soils subjected to waterlogging, as the water excess may cause flowering delay and corm decay. On the other hand, Pereira et al (2009) mentioned that gladioli are quite susceptible to water shortage, resulting in uneven, shorter, and lowquality flower stems, while Tombolato et al (2004) and Paiva et al (2012) reported that water deficit may cause leaf burn and accelerate flowering. Water should then be often provided so that the soil is kept moist, thus plants may produce flower stems of appropriate length and matter (PAIVA et al, 2012).…”