Do not sterilise too many seeds in one Eppendorf tube because their drying may cause a problem. In case the seeds would clump, use a sterile tooth-pick to break the clumps before plating the seeds. The growth rate of roots is important for obtaining fine suspensions. The roots should be white, actively growing and not yellow-brown or green. A dark incubator may be useful, since we have found considerable differences between the growth rates of cell cultures grown in the dark in comparison to those grown in the light.
Great care has to be taken to ensure aseptic conditions.
Flame the neck of flasks well before opening them. Constant swirling of the flask and moving the pipette is necessary to avoid clogging. In the case of certain Arabidopsis mutants, the root development may be inhibited and it is thus difficult to obtain suitable amount of starting root material. By initiating seed- derived calli usually this problem can be successfully overcome. Such cultures reach their exponential phase between days 2.5 and 5.5.