Ex situ seed conservation of Brazilian cacti

Resumo

Evaluation of the seed germination is an important aspect to the determination of seed longevity and, consequently, plant conservation. The aim of the present study was to analyze the effect of storage time on seed germination for eight species of Cactaceae. Seeds placed in cold storage (7 ± 2°C) in periods ranging from 24 to 30 months. The effect of storage time was analyzed through a comparison of stored seeds and recently collected seeds that have been evaluated before storage. Throughout the storage period, seeds from Pilosocereus pachycladus subsp. pachycladus and Pilosocereus tuberculatus maintained germinability similar to that of recently collected seeds. Germinability was reduced for seeds from Cereus albicaulis, Cereus jamacaru subsp. jamacaru and Pilosocereus pachycladus subsp. pernambucoensis, but the seed germination remained above 50%. Drastic reductions in germinability occurred after storage for seeds from Cereus pernambucensis subsp. fernambucensis, Pilosocereus chrysostele and Pilosocereus gounellei subsp. gounellei. No significant differences in the other germination variables were found for any of the species studied. Based on the present findings, the ex situ conservation of germplasm through a seed bank in cold storage is an effective method for the conservation of seeds, as the majority of seeds maintained viability greater than de 50% after the storage period.