V C Pence1, M F Chaiken2. 1. Center for Conservation and Research of Endangered Wildlife (CREW). Cincinnati Zoo and Botanical Garden, 3400 Vine Street Cincinnati, OH 45220 USA. valerie.pence@cincinnatizoo.org. 2. Center for Conservation and Research of Endangered Wildlife (CREW). Cincinnati Zoo and Botanical Garden, 3400 Vine Street Cincinnati, OH 45220 USA.
Abstract
BACKGROUND: The seeds of oak (Quercus) species cannot be conserved in conventional seed banks and require cryobiotechnologies for long-term, ex situ conservation. OBJECTIVE: To evaluate shoot tip cryopreservation as a method for conserving oaks ex situ. MATERIALS AND METHODS: Droplet vitrification was tested on tips from shoot cultures of four oak species; the effects of three preculture and recovery growth conditions on survival and growth were tested with Q. virginiana. RESULTS: Shoot tips of Q. virginiana gave the best survival through liquid nitrogen exposure (56%), compared with Q. hinckleyi (20%), Q. suber (12%), and Q. gambelii (0%). In further tests with Q. virginiana, recovery in the alternating temperature regime (27 C / 151C, 16 h / 8 h) gave significantly better survival than at constant 21sC and significantly better growth than constant 26CC. CONCLUSION: While there are species differences in the response to droplet vitrification, these results indicate that shoot tip cryopreservation should be explored further as a conservation tool for oaks.
BACKGROUND: The seeds of oak (Quercus) species cannot be conserved in conventional seed banks and require cryobiotechnologies for long-term, ex situ conservation. OBJECTIVE: To evaluate shoot tip cryopreservation as a method for conserving oaks ex situ. MATERIALS AND METHODS: Droplet vitrification was tested on tips from shoot cultures of four oak species; the effects of three preculture and recovery growth conditions on survival and growth were tested with Q. virginiana. RESULTS: Shoot tips of Q. virginiana gave the best survival through liquid nitrogen exposure (56%), compared with Q. hinckleyi (20%), Q. suber (12%), and Q. gambelii (0%). In further tests with Q. virginiana, recovery in the alternating temperature regime (27 C / 151C, 16 h / 8 h) gave significantly better survival than at constant 21sC and significantly better growth than constant 26CC. CONCLUSION: While there are species differences in the response to droplet vitrification, these results indicate that shoot tip cryopreservation should be explored further as a conservation tool for oaks.