Date: Thu, 18 Feb 1999 09:52:42 -0500 From: "Douglas W. Darnowski" <darnowsk@staff.uiuc.edu> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg491$foo@default> Subject: Aldrovanda culture
Regarding Aldrovanda culture, I have accidentally found a large increase in
growth when placing Japanese-form plants in a tank with guppies, along with
the usual rushes, Lemna, etc. Whereas similarly grown plants without fish
present have not branched during the winter, these plants have grown
vigorously (increase averaged 3-5 growing points per original growing point
during 6-8 weeks). I had been hoping that the fry from the guppies would be
caught by the Aldrovanda, but the baby fish turned out to be too large. (I
have tried to raise Daphnia magna and a few other crustaceans (using
various techniques) as an appropriately-sized prey species without great
success. Any advice on that point?)
I do not yet know why this has occurred, but my first suspicion is elevated
CO2 due to respiration by the fish.
These plants are being kept at about 60F/15C night and 70F/21C day, with
14h day/ 10h night. The fish have been well fed, so I assume that
inorganic nutrients are abundant (haven't yet tried to measure). The
plants have stopped producing large traps depite not becoming fully
dormant (or the fish have been eating the traps--I haven't had a chance
to observe this closely enough as the plants are at home--my pay comes
for working on soybean molecular and cell biology). Perhaps increased
nutrient levels are causing suppression of carnivory, or perhaps this is
partial dormancy.
The petioles are all much more robust than on leaves from plants, and their
color is lighter but not pale, as if more body color (e.g. white flavonoid)
is present. The stems seem to be less robust than for plants cultivated
otherwise.
This is anecdotal since it only concerns approx. 6 plants (Japanese form; I
am calling a single growing point not attached to another enlarged growing
point) in one tank, and I have started a similar smaller tank for
Australian red Aldrovanda. Once summer comes, I am planning a more
systematic experiment, with replicates and controls, to determine the
effect on Australian, Japanese, and Polish Aldrovanda, to measure CO2 and
nutrient levels, etc.
If this effect turns out to be consistent among the various Aldrovanda
clones in cultivation, it could be useful for increasing material. Plants
could then be returned to fish-free conditions for resumption of trap
production and carnivory.
Does anyone have similar experience with Aldrovanda and fish? Also, is
there an ichthyologist or someone who is a fish hobbyist who can recommend
a species of fish which would reproduce in captivity and the fry of which
would be of an appropriate size for Aldrovanda to catch?
Doug Darnowski
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Douglas Darnowski Department of Crop Sciences 384 ERML 1201 West Gregory
Drive University of Illinois Urbana IL 61801 work ph: (217) 244-6150
fx: (217) 333-4777
home ph: (217) 356-6606
fx: (217) 356-4454
email: darnowsk@staff.uiuc.edu
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