Emergence and early development of seedlings of Mimosa ophthalmocentra Mart. ex Benth.) irrigated with brackish water

Resumo

The species Jurema-imbira (Mimosa ophthalmocentra) is typical of the Caatinga of Northeast Brazil and has medicinal properties; besides being also used by timber industry. The study aimed at assessing effects of irrigation water salinity on emergence and early development of seedlings of jurema-imbira (Mimosa ophthalmocentra Mart. ex Benth.). For this, seeds were manually extracted from the pods of matrix plants and sown under greenhouse conditions in polystyrene trays and irrigated with brackish solutions calibrated to electrical conductivity of 1.5, 2.5, 3.5, 4.5 and 5.5 dS m^-1; and a treatment with tap water with salinity level of 0.5 dS m^-1 was used as control. The experiment was conducted in October 2013. Parameters assessed were: seedling emergence, emergence speed, seedling height, root length, stem diameter, dry mass of shoots, dry mass of roots and total dry mass of seedling. A completely randomized design was used with six treatments, and four replications each consisting of of 25 seeds per treatment. Adjustment of nonlinear and polynomial regression curves, which was used to estimate behavior of variables assessed was performed with aid of software Sigmaplot®. Salinity negatively affects all variables directly proportional to its increase in the irrigation water, with the greatest seedling development at a dose of 1.5 dS m^-1.