Re: Plants

["David A. Youngker" <nestor10@mindspring.com>]

From: Eric Martina
Sent: Monday, November 13, 2000 12:20 AM
Subject: Plants


> I was looking at the krib on info on plants, and I think I am
> more confused now than ever. I have a newly set up and
> planted tank...
>
> I have been leaving the lights on for about 15 hours a day.
> After reading the stuff at the krib I realize that that is too
> much and I plan on reducing that to 12 hours a day
> (should I go less?). The tank has been set up and planted
> for about three weeks and I have already had to scrape the
> sides off of algea once, and it is coming back...

Confused is right. For one thing, this is the Apisto List, not the Aquatic
Plants Digest!

To help with your problem, though, you are correct about the excess
photoperiod. About the only plant that will be capable of utilizing 15 hours
of daylight *are* the algae.

Diana Walstad cites a couple of studies in her book "Ecology of the Planted
Aquarium" that show, regardless of the length of day, aquatic plants tend to
concentrate most of their photosynthetic activity to the morning hours to
coincide with available CO2 concentrations. CO2 will be at its highest at
daybreak, since almost all organic activity is geared toward generating the
gas during the hours of darkness, and those levels taper off with
consumption rather quickly.

And although I imagine this wouldn't necessarily apply to amphibious plants
like Hygrophila, they are still constrained by genetics and environmental
adaptation to much less than 15 hours of lighting. I _do_ know that
terrestrial plants are dependent upon a light- sensitive enzyme that is, in
turn, dependent upon particular lengths of *darkness* to build to certain
"trigger" levels that key the plant to changing seasons. Since most of the
plants we use in the hobby come from areas that don't lie "dead on" the
equator, then I would imagine that they key on photoperiods to some extent.

But on top of that, your tank hasn't really been established long enough for
the plants to settle in and be _able_ to outcompete the algae for nutrients
in the water column. A well- functioning planted aquarium just isn't the
type of system you can throw together and then simply flip the "ON" switch
to have it fully operational.

Those are just some of the obstacles you have to overcome. I could name
quite a few others, and really spend some time on pointing you in a better,
safer direction. But as I said, this isn't the appropriate forum to discuss
these issues. Drop by either rec.aquaria.freshwater.plants (as I'm surprised
you broke your multiple posting habit this time around) or the Aquatic
Plants Digest, and I, along with several others, can spend some "quality"
time on the issue...

-Y-

David A. Youngker
nestor10@mindspring.com




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