African Journal of
Agricultural Research

  • Abbreviation: Afr. J. Agric. Res.
  • Language: English
  • ISSN: 1991-637X
  • DOI: 10.5897/AJAR
  • Start Year: 2006
  • Published Articles: 6786

Full Length Research Paper

Gas exchange in castor bean cultivars in response to foliar application of potassium silicate

Jussara Cristina Firmino da Costa
  • Jussara Cristina Firmino da Costa
  • Department of Plant Science, Federal University of Viçosa (UFV), Viçosa, Brazil.
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Genelicio Souza Carvalho Júnior
  • Genelicio Souza Carvalho Júnior
  • Agricultural Sciences, Embrapa Cotton, State University of Paraíba (UEPB/Embrapa), Campina Grande, Brazil.
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Rosiane de Lourdes Silva de Lima
  • Rosiane de Lourdes Silva de Lima
  • Academic Unit of Agricultural Engineering, Federal University of Campina Grande, Campina Grande, CEP: 58.109-970, Campina Grande, Brazil.
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Hans Raj Gheyi
  • Hans Raj Gheyi
  • Nucleus of Soil and Water Engineering, Federal University of Recôncavo of Bahia, Cruz das Almas, CEP: 44.380-00, Bahia, Brazil.
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Valdinei Sofiatti
  • Valdinei Sofiatti
  • National Center for Cotton Research, Embrapa / Cotton, Oswaldo Cruz Street, 1143, Centenary, CEP: 58428-095, Campina Grande - PB, Brazil.
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Maria Roselita André Soares
  • Maria Roselita André Soares
  • Department of Biology Science, Federal University of Paraíba, Areia, CEP: 58.397-000, Paraiba, Brazil.
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  •  Received: 05 June 2016
  •  Accepted: 28 September 2016
  •  Published: 13 October 2016


Since silicon and potassium are nutrients that influence plant physiological and biochemical aspects, the combined use of these minerals in the fertilization of cultivated plants has been increasingly investigated. This study aimed to evaluate the gas exchanges (Net photosynthesis, Stomatal conductance, Transpiration, Water use efficiency, Carboxylation efficiency, Internal carbon concentration, Chlorophyll a, b, total, Carotenoids and the Chlorophyll a/b ratio) of three castor bean cultivars in response to the foliar application of potassium silicate (PS). The assay in design of randomized blocks, was conducted in a factorial 5 × 3, five doses of potassium silicate (0; 222; 444; 665 and 836 mg L-1) and three varieties of castor bean (BRS Energia, BRS 149 Nordestina and BRS 188 Paraguaçu), with three replications and 45 plants per. The promising effects of foliar fertilization using PS in castor bean plants depend on the genotype. Foliar application of PS increases photosynthetic capacity, stomatal conductance, water use efficiency, chlorophyll a, b, total, carotenoids and the chlorophyll a/b ratio, besides reducing water losses through transpiration.

Key words: Foliar spraying, Photosynthesis, Ricinus communis L., Silicate fertilization