Rotala Wallichii "closing"

[Danny]

Hi guys, just wondering why Rotala Wallichii opens and closes it's leaves while the light is on?

I figure it's because it had taken in all the nutrients etc it can so protects it's self or something but looking for a proper explanation of what's going on please.

 

[Tim Harrison]

I think it just means they've finished photosynthesising and close up to limit the damage further exposure to light might cause; closing up reduces the amount of leaf surface area exposed to light.

 

[Danny]

I think it just means they've finished photosynthesising and close up to limit the damage further exposure to light might cause; closing up reduces the amount of leaf surface area exposed to light.

Thanks Tim that is what I thought but know very little so wasn't sure if I was even near right or not,that does totally make sense though.

 

[zozo]

You might find Carcadian Rhythms very interesting..

In plants, it was realized that the leaf movement rhythm was only one among many rhythms that included germination, growth, enzyme activity, stomatal movement and gas exchange,

http://www.plantcell.org/content/18/4/792

For very long it was believed that these rhythms where stimulated by the movement of the earth and other inveronmental conditions, lights cycle. temperatur, etc. etc. But taking plants to space labs proofed that parts of these rhythms are endogenous in the plants. But still light cycle and temp changes etc. also can trigger this.

I noticed it myself with having the luck with making a water lily flower in november in my aqaurium. It was a day flowering lily, that closes it's flower during the night. Such a flower lives a cycle 5 days.. The tank this lily was in stands 1 metre away from an east faced window. so it recieves indirect daylight. And had a artificial light cycle of 14 hours with 10 hours 100% from 8AM to 10PM.. In november it is about getting dark at 5PM in the afternoon. And what baffled me, even tho the artificial light above the tank was still at 100%, the lily flower was closed at 5 o clock. It reacted to the indirect day light from the window and didn't mind the 100% artificial light. While i notice lily flowers outdoors in the summer staying open to a much later time than 5Pm. So i guessed it was the day light cycle triggering this. And if so, that kinda tells to me that there is something in daylight to what the plant reacts to, something our artificial light doesn't have. What ever that might be? A color? I don't know.. It was a mind boggling experience, fooling a lily in november to flower under artificial light and still that little daylight it recieved played a part in her cycle she prefered over the artificial source. Or something in the earths rhythm the plant pics up..

 

[Tim Harrison]

Thanks Tim that is what I thought but know very little so wasn't sure if I was even near right or not,that does totally make sense though.

Well it's only a thought, maybe Clive or Darrel know different.

And if so, that kinda tells to me that there is something in daylight to what the plant reacts to, something our artificial light doesn't have. What ever that might be? A color? I don't know..

I've long since thought that Spectrum (quality of light) is important to the health of all angiosperms including the "aquatic" ones. Not just in terms of growth rate but in terms of plant morphology, reducing the impact of resource limitation, and triggering life-cycle processes.

For instance, if I recollect correctly, there was some research a while back that suggested the red part of the spectrum can encourage the compact growth we as aquascapers find attractive.

 

[foxfish]

Well it's only a thought, maybe Clive or Darrel know different.

Well your thoughts are exactlyy what I have previously read on this forum & is something I have witnessed many times when it was normal to use 12 hours of light.
I don't know if it is correct though....

 

[Danny]

Cheers guys,

Foxfish, when you say "was" normal to have 12hrs of light, what's "normal" now then?

I'm running on about 14hrs on average as it's a house tank not just my bit of fun lol but yesterday was closer to 16hrs when I noticed it had closed up.

 

[Tim Harrison]

Around 6-8hrs is usual. A 6hr photoperiod is recommended to start with, until the tank becomes biologically stable, with a gradual increase to around 8hrs thereafter.
I start with a 6hr photoperiod and pretty much stick to it throughout the life of the scape.
Although, I have the light on very low intensity for 3hrs either side of that with a short ramp up and down; just enough light to view the fish and the colours of the plants, but probably not enough to encourage photosynthesis and algae problems.