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Re: [AGA-Member] SYMPOSIUM ON AQUATIC PLANTS January 2006 Brussels

Faruk Gençöz wrote:

The location theory is interesting and seems to have evolutionary base. I
myself observe the same location spesificity in lakes and rivers here in
Turkey although not exactly as it is  mentioned in the theory. The
evolutionary explanations summerize million years of life experince and I
think this kind of viewpoint surpasses little individual variations.
Sometimes I see vallisneria or sagittaria species in the middle of a deep
river and find a huge colony of myriophyllum or potamogeton species in very
shallow sections.

So it's not just one exception to the "rule", but huge things that suggest other conditions are a lot more important than the theory's idea. I'd have to say, when you're looking at conditions in the wild, you're the local expert for the rest of us homebodies--what do you think is happening?

On the other hand I agree with the location theory that different collonies of one specific species tend to be located in the
similar environmental conditions (e.g. light, speed of stream, depth) in the
same river.


That's interesting--for an aquarist, of course you start wondering about things that are hard to test for, such as relative light levels in different depths. In one area, perhaps the water clarity is different, and it's the light levels that are controlling where they are.
Or perhaps some plants are more affected than others by the substrate--maybe that's where the sandy bits that are easier for flood fragments to root into, or maybe that's where the more clay-based areas retained a lot of nutrients. Or maybe that's where the leaching ground-water with more nutrients is seeping out of the riverbed.
I find on other horticultural plants that they have very definite preferences on soil texture and chemistry and aeration and of course moisture levels at different seasons, and one can see it reaching back in odd ways to the ancestral environments they came from. They show preferences for how recently the ground has been disturbed; I suspect that vals are probably like the colonizers that pop up in disrupted environments first, and then slowly give way to plants that prefer ground that's been stable (and even heavily compacted) for a long time, more like some of the more fragile wildflowers that only grow in protected loamy soils with a lot of leaf litter built up over the years. I suspect the crypts are more like that last bunch, since they don't like being moved very much!
There's be pretty extreme differences in the microbiology of those two environments on dry land, and I think that would be true of an aquatic one, say from the accumulation of mulm in the gravel (or not).

Another interesting thing is that crypto melting seems a unique phenomena
among cryptos not among rosette plants.

Yes, that's one of my problems with the "area" theory, aside from over-generalizing about "jungle" streamside conditions such as streamside canopy, or lack of it. And the water volume and velocity could vary enormously in a stretch of a kilometer.

Other rosette plants which should
share the same location (according to the location theory) do not show an
immediate decay reaction. I never saw any echinodorus melted in one day
though vallisneria sometimes gets brown within one night.


As best I recall, both vals and swords are New World (correct me if I'm wrong) and all the crypts are in various areas of Southeast Asia, but it can't be just regional or monsoon-based. The crypts alone cover very different water chemistries. I know more about the easy Sri Lankan hard-water crypts, for example (and I'm no expert, by any means) but something that would affect plants in both very hard and very soft waters over such a broad area, without causing the same event in other rosette plants, sounds really strange. Why is it an advantage to the crypts so they all do it, to varying degrees, but other plants have not developed parellel traits to match that advantage?
Odd stuff.
I know Jan Bastmeyer had an expert's site on Crypts, (isn't his one of the links on the AGA website too?).
I don't know what research might have come out about this, I know people were interested in the particular trigger mechanisms, what conditions were setting it off, and how those could possibly influence cellular functions in the plant's leaf tissues.
I remember reading speculations that it was the perfectly normal separation of cell layers that commonly appear in many plants. Many such events are well understood as initiated by ethylene gas, which also triggers fruit to drop (with structural differences in the cells affected, it ripens fruit as well) and leaves to be shed in the fall. But there's some chemical trigger that has to set off the gas-mediated reactions. I think I just repeated your question, in only slightly different words!

FYI, in case you haven't seen it...
http://132.229.93.11/Cryptocoryne/index.html
and he has a recent link to a cultivation page for the European Crypt Society, if you're interested.
http://www.cryptocoryne.de/crypto.html


Faruk


-----Original Message-----
From: aga-member-bounces@thekrib.com
[mailto:aga-member-bounces@thekrib.com]On Behalf Of Heather J Gladney
Sent: 22 Eylül 2005 Perþembe 09:29
To: Aquatic Gardeners Association Member Chat
Subject: Re: [AGA-Member] SYMPOSIUM ON AQUATIC PLANTS January 2006
Brussels


Faruk Gençöz wrote:



I remember the article. Thanks.

"might be adaptation to flood/dry cycles with sudden water-level and
water chemistry changes?"

This seems to be a very rational argument, if melting actually occurs
in the wild. I wonder if someone actually observed such an event in
the wild. I also want to know why this plant has a unique adaptation
skill unlike what the stem plants regularly do.



I recall reading in a sometimes-unreliable older aquarium book that
these types occupy different depth and "width" zones along the stream
banks, where the small rosettes would be growing up on shady banks,
while the stem plants are out in deeper water but more direct sun (where
the water imposes a clearing between the trees that overhang the smaller
plants on the banks, is the theory).  It seems to me that too might have
appeared in one of the recent articles, possibly remarks by Diana Walstad??
Stem plants were cited as being in reliably deeper water than the
rosettes like smaller "groundcover" crypts, and when the crypts are
suddenly plunged in deep, different water after being grown emersed (dry
season in the wild) or semi-emersed (as they often are being grown
before sale in aquarium shops) then the CO2 difference alone might be
enough signal to tell them it's no use flapping leaves out there in the
flood, you won't get any light anyway, it's time to live on food stored
in the rhyzomes.
It's a theory.  I'm not sure how you'd go about proving it, but there's
probably some people who might've worked on issues like this (say,
"dry-matter productivity in diferent seasons," etc.) on plants in the wild.
Hope this is some help!



----- Original Message ----- From: "Heather J Gladney"
<hgladney@comcast.net>
To: "Aquatic Gardeners Association Member Chat" <aga-member@thekrib.com>
Sent: Wednesday, September 21, 2005 10:45 PM
Subject: Re: [AGA-Member] SYMPOSIUM ON AQUATIC PLANTS January 2006
Brussels




Weren't there comments in the magazine awhile back (I believe in a
travel article with pictures showing crypts on-site?!?  There may
have been more than one reference?) suggesting that it might be
adaptation to flood/dry cycles with sudden water-level and water
chemistry changes?  Speculation by the aquarists, as best I recall,
no proof of it.
Anybody remember?
Heather

Faruk Gençöz wrote:



"Cryptocoryne melting" might be a good title for an aquarist to
submit a paper to the symposium. Has anyone encountered an example
to crypto melting in their natural habitat? And would you have an
idea about the ecological role of crypto melting? I am not
questioning the role of regular melting seen among aquatic vascular
plants. In this case, the lower portion of the stem decays so that
the living upper part separates itself from the lower part to travel
down the river. This way seems very practical and functional to find
a suitable new place to reproduce and to enlarge the original
colony. Crypto melting seems to be a liltle different. It occurs
very fast and in general only the roots remain alive. So, rather
than trying to survive in another place, this plant seems to try to
re-generate possibly a more resistant generation. Why is that
difference?

Faruk



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