Cryopreservation of Salix species using sections from winter vegetative scions.

Twigs of Salix species are candidates for cryopreservation procedures because they become tolerant of freezing temperatures during mid-winter. We examined several variables in developing a two-step cryopreservation procedure for sections from these twigs. Samples of Salix triandra cooled to -30 or -35 degree C and then transferred to the vapor phase over liquid nitrogen gave the greatest percent shoot formation.

Cracking in a vitrification solution during cooling or warming does not effect growth of cryopreserved mint shoot tips.

No obvious decrease in viability or in the ability of mint shoot tips to develop into a shoot occurred during vitrification when the external glass cracked upon either cooling or warming. Samples within semen straws did not show a decrease in survival over three cycles of cooling and warming either in the presence or absence of cracking. No physical defects were visible in treated shoot tips.