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Re: APD V4 #390 - Rotten roots

> Date: Thu, 6 Jul 2000 14:15:15 EDT
> From: Bob Dixon
> On Thrusday two weeks back I was setting up a spawning tank...and ended up
> taking home a couple bunches of Cabomba carolinianus and a potted
> watersprite, probably C. silisquosa.  When I unpotted the water sprite, i
> noticed the roots in the rockwool were brown and smelly...

> The cabomba did fine...The watersprite proceeded to slowly turn brown.
> There were three rootstocks altogether.  Two days ago I was doing tank
> maintenance and sucked one of the three out through the siphon and just
> let it go with the waste water.  The other two, while the old growth
> continues to slowly die away, also is putting up new, very healthy-looking
> shoots...
> Has anyone else had Ceratopteris go through this and come out healthy?  Or
> it  likely that in the end the stuff will just keel over and die?

The plants you're describing are reacting to a sudden change in the
environment and experiencing their own form of "Crypt melt". New shoots and
growth are an excellent sign, and means you should have no major problems
establishing the plant. Luckily, Ceratopteris is one of those plants that
seem to propagate even from just a small leaf cutting getting away from you
in the tank. Trust me, one good piece will be all you ever need to get

The root stock that dies back *completely* is another story.

The rotting of the root system is caused by simply "chucking" the potted
plant into a display tank when it arrives, rockwool and all. Rockwools's not
the best type of medium for submerged substrate. It works wonders with an
"ebb- and- flow" type of arrangement, where the substrate is flooded
periodically and allowed to drain. The periods between the "floods" act to
provide aeration and keep the roots from standing constantly submerged.

Start a cutting in the emersed state with its roots in rockwool, and the
plant expects to put out terrestrial- type growth supported by aerated root
systems. Some plants can't make the switch from emersed to submersed states
as quickly, since they must also restructure the root system concurrently
with the leaf structure. Most plants don't have to deal with immediate,
complete and long-term flooding - levels usually increase at a slower pace.
So, to simply place it in water as a complete "package" puts it in a
position where circulation and aeration are cut off from the roots at too
quick a pace.

It's also the reason I normally recommend removing the rockwool when
planting new specimens. Others consider the amount of garden- type nutrients
in the rockwool to be a bigger problem and make the same recommendation.
Fact is, though, that even with amphibious plants there are quite a few that
can't stand up to having their roots immediately flooded and must expend a
considerable amount of energy into shifting the type of growth produced. If
the nutrients can't come from the roots, then established growth is
sacrificed as a nutrient source...


David A. Youngker
nestor10 at mindspring_com