We have been having a recurring problem with "sterile" seeds and are
wondering if anyone could help. We normally sterilize our seed for sowing
on sterile plates, etc by washing 30 sec with 70% EtOH followed by a 10 min
soak in 30% Chlorox. This works great for most applications however when we
sow these seed in MS media + 3% sucrose shaker cultures for 2-3 weeks we often
have contamination problems with what I call "ball fungus". The fungus is
very slow growing and so does not appear until at least 2 weeks after sowing.
Colonies of the fungus are small to large white balls hence my name for it.
My question is.....are we not treating long enough with Chlorox to kill
off ball fungus spores? Can the seeds tolerate higher concentrations of
Chlorox? Are there any alternative methods of sterilizing (I seem to remember
something on the network a while back about microwaving seed)?
Any input on this subject will be appreciated.
Melissa Melan mmelan at lucy.wellesley.edu
Department of Biological Sciences
Wellesley, MA 02181