Among the long term conservation activities, drying is fundamental since the seed water content directly affects the seed longevity. The aims of this study were to evaluate the effect of pre-humidification after ultradrying on the physiological quality of sunflower seeds. Seeds with 4.7% water content were re-hydrated to 10.2% water content and slow drying was conducted in a dry chamber and fast drying in silica gel to 7.7, 3.2, 2.9% and 5.3%, 3.2 and 2.1%, respectively. After drying, seeds were submitted to humidification, or not, in a "gerbox" type box to 15.8 to 17% water content and evaluated for the characteristics germination, weight of root dry matter, shoot and total seedlings and the electric conductivity test. A randomized complete design was used in a 5 (water content) x 2 (with and without humidification) factorial arrangement. Germination was not affected by fast drying, while seeds submitted to slow drying to 2.9% water content presented reduced germination. Sunflower seeds can be dried to 3.2% of water content, without decrease in germination or vigour. The humidification treatment after drying results in better root development and lower electric conductivity values in dried seeds.
desiccation; Helianthus annuus; germination; vigor
