Treatments to break the dormancy of Cassia fistula L. seeds

Abstract

Cassia fistula L. (Fabaceae – Caesalpinioidea) is a forest species that is propagated by seeds. To promote the production of seedlings of C. fistula it is necessary to break the natural dormancy of its seeds, which is caused by the seed tegument that is impermeable to water. The goal of this study was to establish a pre-germination treatment for germinating C. fistula seeds. The seeds were subjected to the following treatments: control – intact seeds (T1); mechanical scarification with sandpaper nº 80 on the side of the seed (T2); mechanical scarification with sandpaper nº 80, followed by immersion in water, at room temperature, for 12 and 24 hours (T3 and T4, respectively); immersion in sulfuric acid for 1, 5, 10, 15, and 20 min (T5, T6, T7, T8 and T9, respectively); and immersion in water at 100°C until cool (T10). We evaluated the percentage of emergence, first count emergence, emergence speed index, and the length and dry mass of the seedlings. The treatment that involved immersion in water at 100°C did not break the dormancy of the seeds. The highest percentage of emergence was for the treatment that scarified the side of the seeds with sandpaper nº 80.

Keywords

• Chuva de ouro
• Forest seeds
• Scarification
• Seed analysis