First the good news. Yes, cells can be stored at liquid N2
temps for years and successfully thawed later. Now the bad news.
It doesn't work well with differentiated tissue/whole organisms.
A major problem is the amount of cell death that occurs during
the freezing/thawing process. Death rates of 90% are not uncommon,
and don't really matter when working with rapidly growing cells.
It would probably be feasible to freeze callus tissues/dissociated
cells. Working out freezing media can also be tricky. Breeders
freeze bull semen all the time, for shipment and storage. Zoos,
on the other hand, cannot successfully preserve endangered rhino
sperm by freezing. So when the London Zoo wants to mate their rhino
with one at the San Diego Zoo, they ship the whole beast. This is a
big problem when maintaining genetic diversity with small populations
of endangered species. Just a side note.
Jeff