Effects of Aluminum and pH on Germination of Echium plantagineum L.

The objetive of this study was to identify the effects of aluminum concentrations and pH levels of solution on germination of Echium plantagineum L. seeds. Three different experiments were carried out in completely randomized design with four repetitions. In the first experiment, we used aluminum sulfate solutions in concentrations of 0.0; 0.3; 0.6; 1.0; 2.0; 3.0; 4.0; 5.0; 6.0 and 7.0 cmol c L -1 and in the second experiment, solutions with different pH, 3.0; 4.0; 5.0; 6.0; 7.0; 8.0; 9.0 and 10.0. In the third experiment, we carried out a factorial (4x4) with aluminum sulfate solutions (0.0; 2.0; 4.0 and 6.0 cmol c L -1 ) and pH (4.0; 5.0; 6.0 and 7.0). It was evaluated the germination of Echium plantagineum L. at four and 14 days after seeding (DAS), germination speed index, primary root length, aerial part and dry mass of seedlings. The presence of aluminum reduced the germination by 27 and 40% at four and 14 DAS, respectively, in concentrations superior to 3.0 cmol c L -1 . The three growth parameters presented linear reduction with the increase of aluminum concentrations. In the second experiment, the solutions with pH of 3.0 and 10.0 provided increases in germination, length of root and aerial part, and little influence in the dry mass of seedlings. In the third experiment, there was significant interaction between the aluminum concentrations and pH levels of substrate. The presence of aluminum in the substrate presented toxic effect on germination of seeds, length of seedlings and dry mass. The pH of the solution has little effect in germination of seeds and in the growth of seedlings of E. plantagineum .