Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 6/14/2004
Publication Date: 8/17/2004
Citation: Volk, G.M., Caspersen, A.M. 2004. The cryopreservation process induces plasmolysis in mint shoot tips. Plasmodesmata 2004. August 17-21, 2004.Monterey, CA. p.118.
Interpretive Summary: Shoot tips contain meristems, regions in which cell division occurs. These meristems must be alive for plants to regenerate after the cryopreservation process. We treated mint shoot tips with various concentrations of solutes to determine how much the cell membrane pulled away (plasmolyzed) from the cell wall within various cell types. We determined that plasmolysis was maintained in the membranes of shoot tips that were fixed in a solution containing glutaraldehyde and paraformaldehyde. We also evaluated the extent of plasmolysis that occurred when shoot tips were exposed to cryoprotectant solutions.
Technical Abstract: Vegetatively-propagated mint plants can be successfully cryopreserved when they are adequately dehydrated and treated with cryoprotectants. Many of these treatments are known to be necessary, yet damaging. The extent of plasmolysis and the effects of these treatments on plasmodesmata have not been reported in the literature. First, we ensured that significant levels of deplasmolysis did not occur during fixation and embedding procedures. We then quantified the extent of plasmolysis during each step of the cryopreservation procedure. In the meristem, the 0.3 M sucrose, 2M glycerol/0.6 M sucrose for 20 minutes, and the PVS2 treatments did not plasmolyze the cells. The plasmodesmata within the shoot tips appeared to be intact after cells were treated with 0.3 M sucrose for 2 hours. Cells were significantly plasmolyzed after treatment with 1.2 M sucrose for 20 minutes during recovery after liquid nitrogen treatment. Some cytoplasm remained associated with the plasmodesmata when plasmolysis occurred. When cells were treated with 1.2 M sucrose, followed by 0.3 M sucrose prior to fixation and embedding, deplasmolysis occurred. These results demonstrate that significant levels of plasmolysis occur during the cryopreservation procedure.