Hidrocondicionamento de Parkia pendula [Benth ex Walp]: sementes com dormência física de árvore da Amaz?nia

摘要

Visgueiro is a neo-tropical tree species with economic and ecologic importance. This work aimed to determine the imbibition time and moisture content of P. pendula seeds necessary to activate metabolism and improve their performance by priming. Stored seeds (2 years) and unstored seeds (7 days) were compared. After clipping, the seeds were kept in water at 15 oC for periods of 4 to 28 hours to reach the desired imbibition degrees (20, 40, 60, 80 and 90%). Seeds were then sown immediately in washed sand in the nursery (4 x 25 seeds / treatment) or dried for 7 days (24±2°C and 68±3% R.H.). Unstored and unprimed (control) seeds showed 59±8.9% germination, which was less than that of stored unprimed seeds (76±11.3 %). Submersion periods exceeding 13 hours reduced germination relative to unprimed seeds. After 4 hours of submersion (seed moisture 26-31%), both unstored and stored seeds increased their performance. Even higher improvement was verified when drying followed submersion. Thus, the positive effects of priming occurred in phase I of the imbibition curve. Hydropriming of 4 hours at 15 oC was found to be a simple and inexpensive method for P. pendula seeds since it increased seedling development velocity, brought the germination percentage of unstored seeds to a level similar to that of stored seeds and increased germination synchronization of stored seeds.