Anatomy and physiology of seeds of Peltophorum dubium (Spreng.) Taub. subjected to storage

Abstract

The objective of this study was to evaluate the anatomical aspects and the physiological behavior of seeds of Peltophorum dubium (Spreng.) Taub. during storage and while undergoing treatments to overcome dormancy. Mature fruits were collected and seeds stored at 5ºC for a period of 360 days and later submitted to treatments to overcome dormancy: T1 - without scarification, T2 - mechanical scarification and T3 - chemical scarification with sulfuric acid for 10 minutes. At pre-established intervals, the seeds were evaluated through an anatomical analysis of the tegument and a germination test. The variables analyzed were tegument anatomy, germination percentage, germination speed index and Pearson correlation between tegument thickness and physiological variables. For the anatomical analyses, the seeds were fixed, embedded, and sectioned on a microtome. The thickness of the tegument was measured from the images of the cross sections. The germination test was conducted with four replicates of 25 seeds, carried out on germitest paper at 25ºC with photoperiod of 12 hours. The experimental design was completely randomized in a 5×3 factorial scheme (storage and overcoming dormancy treatment groups), and the means were compared by the Skott-Knott test at 5% probability. The anatomical analysis showed loss of physical resistance of the tegumentary structures during storage. The percentage of germination for the treatments during storage did not differ significantly, however, the rate of germination showed a significant increase when associated with treatments for overcoming dormancy (T2: 7.08 - seeds not stored and 9.29- stored 360 days; T3: 6.01-seeds not stored and 9.42-stored 360 days). Significant correlations were obtained between the thickness of the tegument and the physiological variables analyzed. Storage for up to 360 days promoted tegumentary anatomical modifications, maintained a high germination percentage of the seeds of Peltophorum dubium, and, when associated with treatments for overcoming dormancy, facilitated their action from 180 days of storage, increasing the rate of germination.

Keywords:
Canafístula; Physical dormancy; Germination; Forest seeds