Seed Priming Effects on Germination and Seedling Establishment of Useful Tropical Trees for Ecological Restoration

We assessed the effects of seed priming and soil retainers on seed germination and early seedling performance of useful species in a tropical semideciduous forest in Veracruz, México. We determined mass and water and lipid content in the seeds of Albizia saman, Cedrela odorata, Enterolobium cyclocarpum, and Swietenia macrophylla. The seeds were exposed to hydropriming and natural priming (seed burial inside the soil) and germinated at 25°C and 25/35°C. The produced seedlings were grown in a shade house and planted in a plain terrain and a hillside (slope 75%). Seedling growth and survival were evaluated. S. macrophylla and E. cyclocarpum seeds had the lowest and highest water content, respectively. S. macrophylla and C. odorata had oil seeds. A. saman and E. cyclocarpum seeds had physical dormancy. Natural priming improved germination in A. saman, C. odorata, and S. macrophylla while hydropriming and 25/35°C enhanced germination in E. cyclocarpum. In the shade house, natural priming promoted seedling growth in all studied species and in the field survival of A. saman and S. macrophylla. In E. cyclocarpum, this effect was obtained with hydropriming in the plain terrain. In the hillside, hydropriming and natural priming and 25/35°C improved survival of S. macrophylla and E. cyclocarpum, respectively. Seed burial for 8 days improved germination, seedling performance, and survival. To bury seeds inside a pot placed in a shade house induced natural priming in C. odorata. We suggest natural priming for A. saman, C. odorata, and S. macrophylla, and hydropriming for E. cyclocarpum seeds. Germination pretreatments were inexpensive and easy tools potentially applicable in restoration and conservation programs.