2.7 Cooling
and Cryopreservation
of Recalcitrant Seeds
1. Vacuum pump to generate nitrogen slush (see Note 8).
2. Polystyrene foam cup to make nitrogen slush.
3. Aluminum foil strips (15 Â 35 mm).
4. 2 mL cryovials (e.g., L-Brady) and boxes (e.g., Nalgene
® Cryobox 81 Â 2 mL Vials, Scientific Laboratory Supplies Ltd, UK)
or canes, depending on the cryo-dewar used.
Fig. 1 “Flash” drying devices used for the rapid and partial desiccation of
embryonic axes of recalcitrant seeds. (a) “Flash” drier used in Royal Botanic
Gardens, Kew, based in the design from [5]. In this design air at room
temperature (about 20
C) is moved at 2 m/s using a 12 V computer fan
situated in the middle of a 2 L jar with 450 mL of activated silica gel on the
bottom. Excised embryonic axes are placed in a 8 cm diameter  1.5 cm height
ring with a fine-mesh nylon attached to both ends on top of the fan. (b) “Flash”
drier designed by [23]. In this design air or N 2 gas at room temperature (about
20
C) is passed at 9 L/min through four fish tank air diffusers in parallel evenly
spaced on the bottom of a plastic box (10 cm long, 10 cm wide, and 4 cm deep).
Excised embryonic axes are placed on a fine-mesh nylon supported 2 cm above
the air stones. A lid with a fine-mesh nylon on top can be also used
Cryopreservation of Seeds and Seed Embryos
667
and Cryopreservation
of Recalcitrant Seeds
1. Vacuum pump to generate nitrogen slush (see Note 8).
2. Polystyrene foam cup to make nitrogen slush.
3. Aluminum foil strips (15 Â 35 mm).
4. 2 mL cryovials (e.g., L-Brady) and boxes (e.g., Nalgene
® Cryobox 81 Â 2 mL Vials, Scientific Laboratory Supplies Ltd, UK)
or canes, depending on the cryo-dewar used.
Fig. 1 “Flash” drying devices used for the rapid and partial desiccation of
embryonic axes of recalcitrant seeds. (a) “Flash” drier used in Royal Botanic
Gardens, Kew, based in the design from [5]. In this design air at room
temperature (about 20
C) is moved at 2 m/s using a 12 V computer fan
situated in the middle of a 2 L jar with 450 mL of activated silica gel on the
bottom. Excised embryonic axes are placed in a 8 cm diameter  1.5 cm height
ring with a fine-mesh nylon attached to both ends on top of the fan. (b) “Flash”
drier designed by [23]. In this design air or N 2 gas at room temperature (about
20
C) is passed at 9 L/min through four fish tank air diffusers in parallel evenly
spaced on the bottom of a plastic box (10 cm long, 10 cm wide, and 4 cm deep).
Excised embryonic axes are placed on a fine-mesh nylon supported 2 cm above
the air stones. A lid with a fine-mesh nylon on top can be also used
Cryopreservation of Seeds and Seed Embryos
667