Cryopreservation of Coffea canephora Pierre ex A. Froehner seeds: importance of drying rate and moisture content.

• Autor(a) principal: COELHO, S. V. B.
• Data de Publicação: 2019
• Outros Autores: ROSA, S. D. V. F. da, FANTAZZINI, T. B., SILVA, L. C.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da EMBRAPA (Repository Open Access to Scientific Information from EMBRAPA - Alice)
• Texto Completo: http://www.alice.cnptia.embrapa.br/alice/handle/doc/1114203
• topic: Antioxidant enzymes; Drying in silica gel; Ice crystals; Physiological quality; Rapid drying; Recalcitrant seeds

Seeds of the Coffea canephora species are considered more recalcitrant than those of the Coffea arabica species. They tolerate partial dehydration and they cannot be stored in conventional seed banks at -18ºC because they are sensitive to freezing temperatures. Cryopreservation is a reliable method for storing seeds with these characteristics for long periods. However, preliminary studies are necessary to determine ideal storage conditions. The aim of this study was to investigate the ideal physical and physiological conditions for cryopreservation of Coffea canephora seeds to reduce seed mortality caused by the formation of intracellular ice crystals and to avoid cell damage caused by excessive desiccation. Seeds were subjected to rapid drying in silica gel and slow drying in saturated NaCl solution to moisture contents of 0.20, 0.25, and 0.28 g.g-¹ (dry basis), followed by direct immersion in liquid nitrogen for rapid freezing. Physiological and biochemical analyses were performed to evaluate seed quality before and after cryopreservation. Rapid drying of Coffea canephora seeds to values near 0.20 g.g-1 (db) does not cause reduction in physiological quality. Moisture content of 0.25 g.g-¹ brings about greater survival of Coffea canephora seeds after cryopreservation. Drying rate affects the physiological quality of cryopreserved Coffea canephora seeds, and rapid drying in silica gel is more favorable than slow drying in a saturated NaCl solution. The activity of the enzymes catalase, esterase, glutamic oxaloacetic transaminase, and polyphenol oxidase are indicators of seed quality for Coffea canephora seeds subjected to cryopreservation.