Tolerance to desiccation and freezing of Passiflora alata Curtis cv BRS Mel do Cerrado seeds and pre-germination treatments

Abstract

To define the best storage conditions, it is necessary to know the physiological behavior of the seeds. The objectives of this study was to evaluate the physiological quality of seeds of Passiflora alata Curtis cultivar “BRS Mel do Cerrado” with different water contents and frozen at -20 °C. The effect of pre-germination treatments on seed performance after drying and freezing was also evaluated. Seeds dried until water content of 12.6%, 7.6%, 5.5%, 4.9%, 4.5%, 4.3%, 3.8% and undried seeds (control) with 19.2% moisture were stored at -20 ºC for 100 days. Germination and vigor tests (germination speed index, GSI) were carried out on dried seeds in the presence or absence of a growth regulator (gibberellins + cytokinins) and on frozen seeds, in the presence or absence of ascorbic acid. Seed germination after drying was high, ranging from 78% to 94%, regardless of the use of the growth regulator. Different results were observed for vigor, since greater germination speed was observed in treated seeds. The freezing did not affect germination and vigor of seeds with moisture ≤7.6%, unlikely of frozen with high moisture seeds, which did not germinate. Seeds of BRS Mel do Cerrado cultivar tolerate desiccation at low water contents and do not tolerate freezing at high moisture levels of 19.2% and 12.6%. Ascorbic acid does not increase the germination and vigor of dry and frozen seeds with differents moistures.