Medium for sporulation?
rwinder at PFC.Forestry.CA
Wed Dec 20 12:39:09 EST 1995
In article <4au0ri$pmv at netnews.ntu.edu.tw>, r3603207 at cc.ntu.edu.tw (ccc) writes:
> How to decide a medium for sporulation?
> I am doing screening experiment with Aspergillus niger. I use PDA
>slants to collect the spores. Recently, many strains seemed to loss
>their ability to sporulate, but their parent strains do sporulate.
> Is it too acidic for them to sporulate? I noted that the pH of the
>slants were very low that most of the agar slants were hydrolysed
>after autoclave. I even tried to add calcium carbonate into the medium
>but it didn't work. What should I do to make them sporulate?
One method I've used that works is to autoclave the medium for twice the normal
time (for me, 40 minutes). I'm not sure of the reason- caramelization of
sugars?- but it seems to work particularly well with V-8 juice agar, or
V-8 Juice/ corn leaf decoction mixtures. I work with weed pathogens- I find
the technique works for a broad range of foliar fungi, contaminants,
opportunists, etc., including Aspergillus. I don't find PDA to be very
suitable for maintaining sporulation. Although pH may have some effect, I
tend to wory about the Carbon/Nitrogen ratio of the medium, and the total
amount, complexity, and variety of carbohydrates used as a nutrient source.
RICHARD WINDER Title: Research Scientist
Canadian Forest Service Phone: (604) 363-0773
Victoria, B.C. Internet: RWINDER at A1.PFC.Forestry.CA
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