Growth and gas exchange of purple basil submitted to salinity and foliar nitrogen fertilization

Abstract

Basil is a medicinal and spice plant widely used in the Northeast region of Brazil. However, its production can be affected by the soil salinity and water used for irrigation. For the development of plants in saline conditions to occur, it is necessary that their nutritional status is adequate. Thus, the objective was to evaluate the effect of nitrogen fertilization on growth and gas exchange of purple basil submitted to salinity. The experiment was performed at the Federal University of Paraíba, adopting a randomized block design in an incomplete 5 x 5 factorial scheme, with five electrical conductivities (ECw = 0.0, 0.81, 2.75, 4.69 and 5.50 dS m⁻¹) and five doses of nitrogen (N = 0.00, 58.58, 200.00, 341.42 and 400.00 mg L⁻¹), generated through the central composite design. Plant height, number of leaves, stem diameter, leaf area and root length were evaluated at 45 days. Stomatal conductance, net CO₂ assimilation rate, transpiration, water use efficiency, intrinsic water use efficiency, intrinsic efficiency of carboxylation and leaf temperature were evaluated. The data were analyzed through analysis of variance and regression. Foliar N fertilization attenuated the harmful effect of salt stress, increasing stem diameter, net CO₂ assimilation rate, intrinsic efficiency of carboxylation and leaf temperature. Salinity reduced the growth of basil plants as the ECw rised. Gas exchange was stimulated by salinity and reduced by the foliar N fertilization. The number of leaves and leaf area increased with nitrogen fertilization.

Keywords:

• nitrogen
• Ocimum basilicum L
• saline stress

Acknowledgment

The authors would like to thank to Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and to Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) for financial assistance to the research.

Conflict of interest

The authors declare that there is no conflict of interest.