Cryopreservation of Pistacia vera embryonic axes

Abstract

This preliminary study investigated the conservation of Pistacia vera genetic resources using seeds and isolated embryonic axes. First, the effect of storing seeds in ambient conditions on embryo viability was evaluated by in vitro culture. The germination rate of P. vera embryonic axes gradually decreased from 100% to 31% after 30-month storage of seeds. Cryopreservation may thus be necessary for the long-term conservation of embryos. A simple protocol was set up using embryonic axes. It included a single dehydration step with silica gel prior to direct freezing in liquid nitrogen (-196°C). The optimal germination rate was obtained after 60 min dehydration (water content of 0.2 grams of water per gram of dry weight [g.g-1 DW]). However, 90 minutes of dehydration (0.14 g.g-1 DW) were necessary to obtain seedlings whose qualitative development was equivalent to that of the control embryonic axes.

Keywords

• seed
• dehydration
• water content
• liquid nitrogen
• germination