Seeds of most Prosopis species exhibit hard seed coat dormancy which must be broken to permit rapid germination. Pretreatments tested for breaking the dormancy of Prosopis juliflora seeds consisted of cutting, abrasion, treatment with 30, 60 or 95% sulfuric acid for 2-30 min, boiling water with soaking for up to 5 days, scalding for 2 s to 10 min, and passing through a cow. Sulfuric acid at 95% for 14 or 30 min, 60% sulfuric acid for 30 min, and manual scarification by cutting or abrasion, all gave germination >94%. Immersion in boiling water followed by 24 h soaking, traditionally used by many field workers, gave only 52% germination. Scalding in actively boiling water for 2 s to 1 min gave similar results (55-74% germination). Some 28% of seeds passed through a cow germinated, compared with 13% of untreated control seeds. Abrasion, 95% sulfuric acid for 14 min and boiling water without soaking also increased germination of seeds of P. articulata, P. caldenia, P. cineraria, P. laevigata and P. tamarugo. Scalding for 5 or 10 s increased germination of seeds of each of these species except P. tamarugo in which was reduced by 10 s scalding. With all 6 species, no treatment was more effective than abrasion for breaking the hard seed coat dormancy.
Pasiecznik, N.M.; Harris, P.J.C.; de P. Tavares, J.; Cassama, M. Pretreatment of Prosopis seeds to break dormancy. International Tree Crops Journal (1998) 9 (3) 187-193. [DOI: 10.1080/01435698.1998.9752974]