Utilização de hidróxido de tetrametilamônio na superação da dormência de sementes de Peltophorum dubium (Sprengel) Taubert E Cassia fistula L

Abstract

Use of tetramethammony hydroxide on the extraction of seed dormity of Peltophorum dubium (Sprengel) taubert e Cassia fistula L. The objective of this work was to evaluate the use of Tetramethylammonium hydroxide base (TMAH) in the seeds dormancy of Peltophorum dubium and Cassia fistula, forest species belonging to the family Fabaceae. The work was divided into two sequentially conducted experiments. In the first one, Peltophorum dubium seed was used with mechanical scarification treatments with sandpaper, chemical etching with sulfuric acid 8 and 15 minutes and immersion in hot water at 950C, in comparison with the treatments TMAH concentrate and 50% 12, 24 and 36 hours of immersion, the analyzed variables form germination and IVG. Based on these data, the second experiment was carried out with Peltophorum dubium and Cassia fistula seeds with chemical scarification in 8 minutes sulfuric acid and concentrated TMAH 4, 8, 12 and 16 hours, evaluating root protrusion, germination, IVE, length and dry mass of seedlings. The treatment with 12-hour TMAH concentrate was efficient to overcome dormancy of Peltophorum dubium seeds. The immersion of Peltophorum dubium seeds in concentrated TMAH for a period of more than 12 hours was detrimental to germination and seed vigor. For the Cassia fistula species the concentrated TMAH was eficiente to break dormancy in relation to the control, but it was not efficient when compared to sulphuric acid 8 minutes. The use of concentrated TMAH for 12 hours may be an alternative to overcome the dormancy of Peltophorum dubium, however, not for Cassia fistula.