Comportamento hídrico e crescimento do feijão vigna cultivado em solos salinizados

Abstract

RESUMOA salinização dos solos reduz a capacidade das plantas de absorver água o que, em geral, provoca diminuição na sua taxa de crescimento. As respostas das plantas ao estresse salino são melhor correlacionadas com o potencial osmótico do que com a condutividade elétrica do extrato de saturação do solo. Com o objetivo de avaliar os efeitos do estresse salino no crescimento, evapotranspiração e potencial osmótico foliar do feijoeiro vigna [Vigna unguiculata L. (Walp.)] conduziu-se um experimento em casa de vegetação da Universidade Federal Rural de Pernambuco (Recife, PE, Brasil). Os tratamentos constaram de um arranjo fatorial 2 x 4 composto de duas texturas de solo e quatro níveis de salinidade do solo (4, 8 e 12 dS m -1 a 25 ºC além da testemunha sem a adição de sais) com cinco repetições. Concluiu-se que a salinidade do solo causa redução no consumo de água, no potencial osmótico foliar, na altura das plantas, no número de folhas e na biomassa seca da parte aérea do feijoeiro vigna. Palavras-chave: potencial osmótico, salinidade, feijão caupiHydric behaviour and growth of cowpea cultivated in salinized soils ABSTRACT Soil salinization reduces the capacity of plants to absorb water, and in general causes decrease in plant growth. Plant responses to salt stress are better correlated with osmotic potential compared to electrical conductivity of soil saturation extract. In order to evaluate the effect of salt stress on growth, water use and leaf osmotic potential of cowpea [Vigna unguiculata L. (Walp.)], an experiment was carried out in a greenhouse of the Federal Rural University of Pernambuco (Recife-PE, Brazil). The treatments were in a factorial arrangement of 2 x 4, comprising of two soil textures and four levels of soil salinity (4, 8 and 12 dS m -1 at 25 °C, and the control without salt addition) with five replications. It was concluded that soil salinity causes reduction in water consumption, leaf osmotic potential, plant height, number of leaves and dry biomass of shoot of cowpea.

Growth of cowpea plants inoculated with Rhizobium in a saline-sodic soil after application of gypsum

“…For soil S1, an increase can be seen in the height of the bean plants at levels of 100 and 150% of the GR, followed by a decrease at levels of 200 and 250%, when the EC of the saturation extract of the soil was around 4.7 dS m -1 . These results are similar to those reported by Coelho et al (2013) who, working with cowpea and salinity levels (2.0, 4.0, 8.0 and 12.0 dS m -1 ), found that from an EC level of the saturation extract of the soil equal to 4.00 dS m -1 , drastic reductions in plant height were seen, with values of 75 and 85% for the sandy-loam soil and clayey-loam soil respectively. The authors explain that this reduction in the growth of the vigna bean is due to a decrease in the osmotic potential of the soil solution, which caused a greater difficulty in the absorption of water and nutrients, as well as to the possibility of there being ion toxicity due to the possible excessive accumulation of the sodium cation and the chloride anion.…”

Ponto de murcha permanente fisiológico e potencial osmótico de feijão caupi cultivado em solos salinizados

“…1. Ponto de murcha permanente (-1,5 MPa); ds -Densidade do solo; dp -Densidade de partículas Com o objetivo de estimar a quantidade de sais correspondentes aos tratamentos salinos, realizou-se um ensaio preliminar utilizando uma mistura de sais composta de 2/3 de NaCl e 1/3 de CaCl 2 (Coelho et al, 2013); em seguida, procedeu-se à incubação dos solos empregando-se as concentrações de zero a 5 g dessa mistura de sais por kg de solo, na forma de uma pasta saturada (Richards, 1954). Após a incubação dos solos pelo período de 24 h, foram obtidos os extratos das pastas saturadas e se mediu a condutividade elétrica, o que proporcionou as seguintes equações: y = 6,787x + 2,634 (solo franco-arenoso); y = 4,385x + 2,526 (solo franco-argiloso); em que x é a concentração salina, em g kg -1 e y corresponde à condutividade elétrica do extrato saturado, dS m -1 .…”

Soil water energetic status and cowpea beans irrigated with saline water

“…Souza et al (2011), cultivating cowpea under saline stress, and Coelho et al (2013), using a mixture of NaCl and CaCl 2 , with 0, 4, 8 and 12 dS m -1 , cultivated cowpea under saline stress and found physiological alterations during the development of the crop.…”

“…Many studies can be found in the literature associating salinity with water potentials (Souza et al, 2012;Adolf et al, 2013;Coelho et al, 2013;Souza et al, 2014). In addition, the evaluation of the influence of the type of salt in the irrigation water is of great relevance in studies on salinity in the soil-plant system (Melo et al, 2016).…”