Re: Dark period for plants

Last time I wrote:
> As an experiment to see how it would affect a green algae bloom,
> I turned off all the aquarium lights on both aquariums last Friday.
> They will come back on again Tuesday which makes for 4 completely
> dark days.

The algae bloom was quite severe prior to this operation. Although
it has not completely cleared, it seems to be significantly less.
I think I will need to resort to using the diatom filter even though
setting it up is a bit of a hassle.

> The response of the plants has been very interesting:
> many of the plant types grew quite a lot

Some of the plants which had increased growth during the dark period 
include the Crypts, Aponogeton sp., Hygrophila, Rotala, Cabomba, 
Ceratopteris, Ludwigia and Lobelia cardinalis. Lobelia is normally very 
slow growing but this plant showed unusual growth compared to its normal
rate. Lilaeopsis grew longer leaves than usual. Several leaves of
the Hydrocotyle leucopetala turned quite pale (older ones) while
it continued to grow.

I suspect that there is some kind of a change in the plant growth
regulating hormones which occurs in dim light which provokes this
response when the lighting changes. I think this could only occur
in a plant which is healthy and has a vigorous root system and
perhaps certain reserves. I wonder if this might be another clue
in the puzzle to getting Aponogetons to break from the dormant cycle.