Efeitos da salinidade nas relações hídricas, trocas gasosas e no crescimento de mudas de Jurema-preta (Mimosa tenuiflora (Willd) Poir.)

Abstract

Soil salinity is one of the most limiting factors for plant growth and their ability to survive under these conditions is important for their geographic distribution, forestry and agricultural production in salinized regions. This work aimed to verify the physiological behavior of ‘jurema-preta’ saplings under salinity conditions. The experiment was carried out in the forestry nursery of the Academic Unit of Forestry Engineering/UFCG, with the plants kept in 'leonard' pots. The salinity treatments were distributed in a completely randomized design, with five levels of electrical conductivity (EC) of the nutrient solution (0.5; 2.0; 3.5; 5.0 and 6.5 dS m-1), and four replications. The salinity of the solution was achieved by adding a mixture of NaCl, CaCl2.2H2O, and MgCl2.6H2O salts. At 210 days, plant height and diameter parameters, height growth rate, stomatal parameters, relative water content and dry mass production were evaluated. The salinity affected the changes of ‘jurema-preta’, decreasing all the analyzed parameters. The transpiration rate was less sensitive to salinity than stomatal conductance and photosynthesis. Among the growth parameters, the roots showed greater sensitivity to the employees' salinity levels.