Superação de dormência de sementes e desenvolvimento de mudas de jatobazeiro em substratos alternativos

Abstract

The propagation of the jatoba (Hymenaea courbarilL.) by seeds is highly promising in the recovery of degraded areas. Thus, the present research aimed to compare methods forjatoba plant seeds dormancy overcomingand to evaluate the development of seedlings of this species in alternative substrates. In the first experiment, in screened nursery, a completely randomized design was used, with four replications and seven seed treatments: scarification with sandpaper(SS), SS and immersion in water for 24 h, SS and immersion in water for 48 h, intact seed, seed immersed in water for 48 h and seed immersed in water for 96 h. The seedlings that emergency were counted every other days, from 13 to 51days after sowing, quantifying the emergence percentage, the emergence speed index and the emergence average time.The second experiment, in greenhouse,was composed ofthree replicates, in randomized blocks, being seven substrates were used:commercial substrate (CS); 40% SC + 60% forest humus (FH); 40% SC + 60% charcoal rice husk (CRH); 40% SC + 60% bovine manure (BM); 40% CRH + 60% BM; 40% CRH + 60% FH; e 40% FH + 60% BM. At 50, 70 and 120 days after sowing were evaluated the parameters: seedlingheight, leafsnumber, stem diameter, fresh matterand dry matter of aerial partand roots, and leaf area.At 120 DAS, the chlorophyll index was also evaluated. The scarification with sandpaper and immersion of seeds in water for 24 hours presented a greater emergence (96.4% and IVE = 0.697).The mixture containing 40% FHand 60% BMresulted seedlings with a larger leaf area, chlorophyll index and roots and aerial part dry matter, at 120 days after sowing.