Criopreservação de meristemas apicais de cafeeiro pelas técnicas de droplet vitrification e v-cryoplates

Abstract

Plant genetic resources are strategic for biodiversity conservation and for the development of cultivars adapted to climatic and agronomic conditions. However, their conservation imposes significant challenges, especially in tropical species whose seeds are sensitive to desiccation, have low longevity, and present limitations regarding storage by conventional methods. In this context, Brazil stands out as one of the countries with the greatest biodiversity on the planet and as a global agricultural reference, being the main producer of Coffea arabica L. Coffee propagation is carried out through seeds, with intermediate physiological behavior, characterized by loss of viability and low tolerance to conventional drying processes, making prolonged conservation by traditional methods unfeasible. In view of this limitation, cryopreservation is a technique that has been widely studied for intermediate and recalcitrant species, allowing the storage of plant material for prolonged periods. In this context, two studies were conducted. The first aimed to evaluate the effect of the antioxidants reduced glutathione (GSH) and ascorbic acid (AA), as well as cryoprotectant and recovery solutions, during the prefreezing phase of the cryopreservation protocol, aiming to increase the survival of apical meristem explants of Coffea arabica L., Catuaí Vermelho IAC-144, cultivated in vitro. In the second study, the use of the cytokinins 6-benzylaminopurine (BAP) and thidiazuron (TDZ), and their interaction with the auxin IAA (indole-3-acetic acid), was evaluated to promote increased regeneration and multiplication of shoots from apical meristems and nodal segments of Coffea arabica L., Catuaí Vermelho IAC-144, cultivated in vitro. The results obtained demonstrate the potential of using antioxidants to increase survival rates, exceeding 50% of the explants, and to maintain tissue stability. Regarding shoot regeneration, BAP showed high inductive potential, with an average of more than three shoots per explant. These results show that the application of antioxidants before liquid nitrogen freezing can reduce structural damage and increase the survival of in vitro cultivated explants. However, further studies are needed to determine key points that contribute to the development of cryopreservation protocols and to the conservation of germplasm of tropical species.