Potencial de espécies florestais nativas na fitoextração de sais

Abstract

This study evaluated the effect of salt stress on germination and seedling development of mogno and timburi. Two experiments were conducted: the first was conducted in the laboratory to test the germination of mogno and timburi to salt stress, they were placed and chest gerbox with salt solutions of NaCl at levels of 0,57; 1,73; 2,40; 4,11; 6,49 and 8,37 dS m-1 . The seeds were germinated in incubation chambers (BOD) at 25, 30 and 35 ° C temperatures. The experimental design was completely randomized with four replications of 20 seeds. The results were submitted to anova and Tukey test at 5%. The second experiment was to evaluate the morphology, absorption of macronutrients and sodium, was conducted in a greenhouse where the seedlings of mogno and timburi were produced in the substrate Plantimax ® and reached 15 cm were transplanted to PVC pipes filled with pre-washed sand. The seedlings were subjected to 5 salinity levels (1,73; 2,40; 4,11; 6,49 and 8,37 dS m-1 ). The experimental design was completely randomized design with 5 treatments and 5 replicates for mogno and 5 treatments and 16 repetitions for timburi. Every 15 days were recorded height, stem diameter, and toxicity symptoms and photographed every 10 days. After this period the plants were dried in an oven forced air circulation, weighed, ground and quantified macronutrients and sodium. Results were subjected to analysis of variance and means tested with Dunnett 5%. The percentage and rate of germination of seeds of mogno and timburi decreased with increasing salinity; under salt stress these seeds were able to germinate. The morphology of the plants varied with the salt stress, the height and diameter, the production of shoots and roots dry mass of mogno and timburi seedlings were reduced. The plants tend to increase the levels of Na+ without reducing the macronutrient; reduction occurring only Ca in shoots at 40 days for timburi.