Influence of scartification processes on germination and early growth of Leucaena leucocephala (Lam.) de Wit

Leucaena leucocephala, planta de grande interesse econômico, tem sido objeto de diferentes tipos de investigação. Este trabalho procurou analisar os efeitos de diferentes processos de escarificação em sementes frescas e estocadas sobre o comportamento germinativo e o crescimento inicial. As técnicas de escarificação utilizadas foram: escarificação mecânica; imersão em água quente, por 10 minutos; imersão em ácido sulfúrico concentrado, por 10 minutos, O controle foi dado por sementes intactas. Os testes foram desenvolvidos com 200 sementes, em 10 repetições, e montados em caixas gerbox, forradas com papel-filtro; a rega foi com água destilada e temperatura de 25±2oC e luz controlada. Os resultados demonstraram haver influência estatisticamente significativa (testes t, ANOVA simples, de interação e SNK) dos tratamentos de escarificação, tanto sobre o comportamento germinativo, como sobre o crescimento inicial.Leucaena leucocephala is a species with high economical value and has been subjected to numerous kinds of investigations. This work was designed to develop methods for breaking seed dormancy and induce healthy seedling growth. Dry stored seeds of 1985 crop and fresh seeds of 1986 crop were used. Four treatments of two hundred seeds each were carried out: mechanical scarification; immersion in hot water for 10 minutes; immersion in concentrated sulfuric acid for 10 minutes and untreated. Seeds were incubated in Gerbox boxes, with 20 seeds per box, on filter paper which was moistened with distilled water. The boxes were maintained at a constant temperature of 25 ± 2oC and at a photoperiod of 10 hours light and 14 hours darkness. The results indicated that all seed treatments were effective in breaking seed dormancy. The sulfuric acid treatment resulted in the best early seedling growth for the dry stored seeds, while the hot water immersion led to the best growth for the fresh seeds. Significant differences (by t-test, simple and interaction ANOVA, SNK) were obtained among treatments for both seed germination and early seedling growth