Freezing plant tissue culture cells (?!)

[alvin at unity.ncsu.edu]

	I have quite a few suspension cell lines derived
from Nicotiana tabacum which I may be more interested
in in the future.  I would like to keep these lines
going but we are *very* limited for space such that 
if I keep these lines alive, it takes away space from
other experiments which are currently more important.
	Does anyone know of a way to freeze these cells
down so they can be stored long-term (6 months or so)
and then revived?  Is there any way to store plant 
cell lines?  
	I have asked around and posted this question
on the methods and reagents newsgroup, but haven't had
any luck; I hope someone here knows how to do this!
	Thanks,
	Leigh Thorne (leigh_thorne at ncsu.edu)