At 12:31 AM 10/9/96 -0400, Janice M. Glime wrote:
>Ross,
> I enjoyed your answer to this, and so many other of your responses. I
>am curious about item 4 - providing sucrose. I read this somewhere and
>put it in the botany book I wrote for the course I teach here. When I
>sent the book out for review, the reviewer jumped all over me, saying that
>the sucrose would encourage the growth of bacteria.
Yes any sugar is going to accelerate microorganism growth,
so you have to add hydroquinone or other bacteriostatic
agents to check this.
>We have ignored the
>advice in our lab experiments, but we really haven't seen any differences
>in those with sucrose and those with none.
Some species have plenty of native carbohydrate to supply
the respiration needs of the flowers. Others lack this
endogenous supply, so external sources are needed to
extend vase life. Almost all the packets given to people
who buy flowers at a florist contain a carbohydrate and
a bacteriostatic agent.
>Can you give any specific
>advice on concentration?
Each flower species should be tested to determine the
optimal dose through a dose response. That in itself
makes an instructive experiment. It ties in with the
respiration process, and ultimately to osmosis and
water relations, and also to the concepts of optimum,
luxury, reserves etc. Maybe for one species the distilled
water control lasts just as long! In my own research
on Gaillardia, I used 0.05 M sucrose. This was the
lowest concentration that permitted full growth of
filaments in vitro in a natural time-frame.
>Some have suggested putting aspirin with it to
>prevent bacteria.
Some people have said that, and others say it also
impacts ethylene biosynthesis...though I'm not clear
about which way. Literature on "voodoo" lily shows
salicylic acid stimulating ethylene biosynthesis.
This could be a direct or indirect effect...?
Aspirin is a derivative of salicylic acid, so it
could block that process as a competitive inhibitor?
It would be good to ask Jack Sacalis or George Wulster
at Rutgers about their findings with carnations and
any effect of aspirin on ethylene biosynthesis.
Hydroquinone I know is bacteriostatic and salicylic
acid is not too far structurally from that.
>Sorry I'm not looking for this myself in the
>horticulture journals, but the nearest library with horticulture journals
>is at least 100 miles away (more likely 400) - or in some unknown person's
>basement.
I'm in the same boat! Our library is PITIFUL in terms
of plant science. It is the one drawback to ECSU.
I'm sure the aspirin question is answered in the literature,
but I just don't have resources here to check it out.
I have also heard that putting a copper penny in the
solution works...presumably by adding Cu ions...it is
known that the Ag (silver) ion blocks ethylene action,
so a complex of silver nitrate with sodium thiosulfate
can prolong vase life [but very impractical!]. It is
also known that Co (cobalt) ions block ethylene bio-
synthesis. I'm not sure about this copper connection,
but copper is an essential cofactor for some enzymes.
I wish I knew more...
ross
______________________________________________________________
|
Ross Koning | Koning at ecsu.ctstateu.edu
Biology Department | http://koning.ecsu.ctstateu.edu/
Eastern CT State University | Phone: 860-465-5327
Willimantic, CT 06226 USA | Fax: 860-465-5213
____________________________|_________________________________
Plant Physiology is Phun!
/\|___/\ //\______COOH NH-CH2-CH=C-CH2OH \/OH
| | | | | | || //\___ \CH3 /\|/\\/\\COOH
\/ \/|\/| \\/ \ / N || N | |
/\ | |__|= NH | || || //\//\
| COOH \\ /\ / O
COOH H2C=CH2 N NH
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