callus cultures

[PD101 at PHOENIX.CAMBRIDGE.AC.UK]

I am fractionating membranes from Arabidopsis callus cultures.
Does anyone have experience on optimising
i) reproducibility/consistency of a friable callus culture?
   I know of the methods in "a Compleat Guide", Ecker (1990) Methods 1,186
   and Axelos et al. (1992) Plant Physiol. Biochem. 30, 123
 
ii)Membrane preparation from callus via protoplasts or otherwise?
 
Thanks very much,
 
Paul Dupree,
Department of Plant Sciences,
Cambridge University,
Cambridge CB2 3EA,
U.K.
 
PD101 at phx.cam.ac.uk