ARS | Publication request: SURVIVAL OF MINT SHOOT TIPS AFTER EXPOSURE TO CRYOPROTECTANT SOLUTIONS COMPONENTS

Submitted to: Cryobiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 7, 2005
Publication Date: April 1, 2006
Citation: Volk, G.M., J.L. Harris and K.E. Rotindo. 2006. Survival of mint shoot tips after exposure to cryoprotectant solutions components. Cryobiology 52:305-308.

Interpretive Summary: Shoot tips from plants can be cryopreserved if they are properly treated with cryoprotectant solutions. These shoot tips can be stored at liquid nitrogen temperatures for extended lengths of time and then regenerated into healthy plants when necessary. Researchers commonly use a technique entitled "vitrification" that uses highly concentrated solutions to dehydrate shoot tips. Plant vitrification solution 2 (PVS2), a common vitrification solution, contains glycerol, ethylene glycol, dimethyl sulfoxide, and sucrose. We determined that PVS2 and its components are more damaging when mint shoot tips were exposed to solutions at 22 degrees C compared to 0 degrees C. We demonstrated that glycerol was one of the toxic components of PVS2. Mint shoot tips could be successfully cryopreserved when the glycerol component of PVS2 was reduced. New solutions with lower toxicity and more uniform applicability could be developed when plant vitrification solutions are characterized on a toxicological and biophysical basis.

Technical Abstract: Many plant species can be cryopreserved by treating shoot tips with dehydrating cryoprotectant solutions before rapidly cooling to liquid nitrogen temperatures. Plant vitrification solution 2 (PVS2) is a commonly selected cryoprotectant that contains glycerol, ethylene glycol, dimethyl sulfoxide, and sucrose. The PVS2 solution can be lethal with extended exposure times. Mint shoot tips were used as a model system to identify which of the four PVS2 components cause this damage. Overall, solution exposures at 22 degrees C were more damaging than exposures at 0 degrees C. The glycerol components of PVS2 and plant vitrification solution 3 (PVS3; containing 50% glycerol and 50% sucrose) were damaging at 22 degrees C. Mint shoot tips could be cryopreserved using variations of PVS2 with lower concentrations of glycerol. New solutions with lower toxicity and more uniform applicability could be developed when plant cryoprotectant solutions are characterized on a toxicological and biophysical basis.