title: Cryopreservation of chayote (Sechium edule JACQ. SW.) zygotic embryos and shoot-tips from in vitro plantlets.
abstract: This paper presents the development of cryopreservation protocols for zygotic embryos and apices of chayote (Sechium edule Jacq. Sw.), a tropical plant species with recalcitrant seeds. Zygotic embryos of two cultivars, Ccocro negro (CN) and Claudio (Cl) could withstand cryopreservation, with survival percentages of 10 and 30 %, after desiccation to 23 and 19 % moisture content (fresh weight basis), respectively. Apices sampled on in vitro plantlets of cultivars Cl, 13 and JM were successfully cryopreserved using a vitrification technique. Optimal conditions included the culture of mother-plants for 22 days on medium containing 0.3 M sucrose, culture of excised apices on the same medium for 1 day, loading of apices for 20 min with 2M glycerol + 0.4M glycerol, treatment with a series of diluted PVS2 solution (60 % PVS2 followed by 80 % PVS2 solution for 15 min (cultivar Cocoro Blanco [CB]) or 30 min (cultivars CN and Cl) at each concentration), rapid freezing and thawing, washing of shoot-tips with a 1.2 M sucrose solution, followed by recovery on media with progressively decreasing sucrose concentrations until the standard concentration of 0.1 M was reached. The highest survival percentages achieved ranged between 17 and 38 %, depending on the cultivar.
authors.affiliation: Centro de Investigacion en Biotecnologia, Instituto Tecnologico de Costa Rica (ITCR). aabdelnour@itcr.ac.cr
authors.forename: Ana
authors.initials: A
authors.lastname: Abdelnour-Esquivel
authors.forename: Florent
authors.initials: F
authors.lastname: Engelmann
mesh_terms: D002985:Clinical Protocols; D015925:Cryopreservation / Q000379:methods*; D003451:Cryoprotective Agents / Q000494:pharmacology; D019662:Cucurbitaceae / Q000196:embryology* / Q000254:growth & development; D046508:Culture Techniques / Q000379:methods; D003890:Desiccation / Q000379:methods; D018520:Plant Shoots / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development*; D012639:Seeds / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development*; D015996:Survival Rate; D013997:Time Factors; D014867:Water / Q000032:analysis
chemical_list: D003451:Cryoprotective Agents; D014867:Water