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Faster growth in dim light stressful?


Subject: Faster growth in dim light stressful?
 
> >I suspect that there is some kind of a change in the plant grow
> >regulating hormones which occurs in dim light which provokes th
> >response when the lighting changes. I think this could only occ
> >in a plant which is healthy and has a vigorous root system and
> >perhaps certain reserves. I wonder if this might be another clu
> >in the puzzle to getting Aponogetons to break from the dormant 
> 
> It seems to me the plants grew faster during their dark period b
> were looking for light. The same chemicals that cause plants to 
> turn their leaves toward light are at play.  I suspect dormant A
> without leaves, wouldn't be able to respond this way.

It seems to me that I've read that plants do most of their growing 
 at night (during the dark) rather than while they are 
photosynthesizing.
 
> My question: Is this good for the plants? Wouldn't subjecting th
> periods now and then actually be stressful because it causes the
> in pursuit of light? I suppose once light is restored, the plant
> itself back up through photosynthesis. Is their growth in the da

I doubt it's _good_ for the plants, but they seem to tolerate it 
without problem if they are healthy to start with.  I have twice 
had to cure green water problems with week long "blackouts">  In 
both cases, the algae was completely gone, and the plants were 
fine when I turned the lights back on.  The internodes _were_ a 
little longer than usual, and red plants were a little less red 
than usual, but not as markedly as I've seen in chronically under 
lit tanks.  Growth immediately returned to normal when lighting 
was restored.

I have recommended this method of curing green water blooms a 
number of times, and in most cases it works well.  One caution... 
IMO, it is important to reduce the _amount_ of algae in the water 
befroe blacking out the tank, either through large water changes 
or diatoming.  Otherwise, I'd be afraid that a major algae die-off 
could lower the O2 level in the tank precipitously and endanger 
the fish.

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Karen Randall
Aquatic Gardeners Assoc.
Boston, MA