Curbing diurnal behavior

JoshP12

Member
Joined
8 Dec 2019
Messages
471
Location
Canada
I am just wondering if anyone has noticed their plants open and close as they feel like it and has had success curbing their behavior to your liking.

My rotala rotundifolia + Ludwigia repens would open up starting around 7:00 AM and then when my lights came on at 11:00, they would have leaves almost pointing to the ground; it wasn't until later in the photoperiod that they would perk back up and look nice.

I have now let them dictate my photoperiod: 7:30 - 4:30 ... my pogostemon erectus opens up a bit later than those though (he must be a night owl).

I attributed this to the light that comes in my back window and down the basement stairs to the fish tank ... it is a tiny bit of light (both are covered), but will this cause it?

It is not a huge issue, but I would like to push my photoperiod ... can I curb their behavior by covering the tank with a dark sheet during the off hours or is this just in their DNA?

Josh
 

Hufsa

Member
Joined
22 Aug 2019
Messages
147
Location
Norway
Im watching this thread with great interest, I just happened to make a similar post to my journal.


"For a long time ive been observing the plants being "woken up" by the ambient light in the room and it has left me considering if the ambient light is sabotaging my efforts to slow my plants need for CO2.
The ambient light hitting the tank is increasing in intensity as summer progresses. The window is northeast facing. My timer has been set to 13:00 to 21:00, now 14:00 to 20:00, since I like to view my tank in the evening. But my plants open their tops much earlier in the morning when the ambient light gets to a certain intensity, even if the curtains are closed. They also close their tops before my aquarium lights go off.
Could this mean that they have already had a long photoperiod and are "done" before my artificial photoperiod is even over?

Im tempted to cover my tank with something that blocks the light and keep it on in the hours my lights are off. I would not be happy with this as a permanent solution as I am very lazy, but it would be interesting as an experiment. This would also interfere with viewing the fish while the lights are off :grumpy:

If this helps I guess I will have to try to sell in some blackout curtains and them having to be closed until 14 o clock to my partner. That will be interesting.. :hungover:"
 

jaypeecee

Member
Joined
21 Jan 2015
Messages
1,459
Location
Bracknell
Hi Folks,

You may be interested to know that plants have their own built-in clocks (circadian rhythms) just like we humans, for example. It's fascinating and mind-blowing stuff. Even cyanobacteria are thought to follow a circadian rhythm. For more information, try this for starters:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1425852/

I suspect that this is relevant to the observations you are both making.

JPC
 

JoshP12

Member
Joined
8 Dec 2019
Messages
471
Location
Canada
Thanks for sharing: @jaypeecee -- I will be reading this deeper soon - the picture caught my eye as it looks EXACTLY like my ludwigia.

So ... something cool happened.

My Pogostemon Erectus was closed for about a week at lights on, and I mentioned him being a night owl in my original post.

This morning, he was opened up by lights on :oops:.

I have been more diligent of mitigating ambient light and considered that black sheet trick: @Hufsa

I am going to push my photoperiod again and see if they will start staying closed longer.

Josh
 

tiger15

Member
Joined
14 Mar 2018
Messages
507
Location
USA
I don't think you can curb the diurnal rhythm by blocking out sunlight. Plants can detect the difference of darkness and ambient lighting regardless of the intensity.

I provide a split early morning (7 to 11 am) and late evening (6 to 10 pm) photo periods for my viewing. In winter months when the photo period is turned on before sunrise, I notice that some stems take about an hour to wake up, but no such observation in summer months when sunrise is earlier. I never observe close up of stems in the evening photo period even thought lighting continuous long after sunset. But aquarists who provide lengthy photo period reported close up after 10 hours suggesting that plants get their fill and any longer photo period provision is a waste.

In nature, aquatic plants are also subject to variable sunlight period as many grow in forest edge and the over head sunlight moves and casts shallow at different time. It was also reported that stems in ponds close up in midday due to intense sunlight or CO2 depletion, and reoppen later.

How aquatic plants respond to photo period is not as well understood as terrestrial plants which are known to time flowering, fruiting and hibernation to daylight hours. Questions remain on whether non stem plants also wake up like stems, why some and not all stems manifest wake up, and whether only wake up stems can utilize light for photosynthesis.
 

jaypeecee

Member
Joined
21 Jan 2015
Messages
1,459
Location
Bracknell
I don't think you can curb the diurnal rhythm by blocking out sunlight.

Hi @tiger15

From what I've read, your comment above seems to be spot on. The diurnal rhythm in plants is either 'programmed in' or the trigger is something other than light itself. The only things I can think of are variations in gravitational or magnetic field acting on plants. I'm clutching at straws here, needless to say! But, this is fascinating stuff. Here's another link:

https://www.lettusgrow.com/blog/what-are-circadian-rhythms

JPC
 
Last edited:

jaypeecee

Member
Joined
21 Jan 2015
Messages
1,459
Location
Bracknell
The diurnal rhythm in plants is either 'programmed in' or the trigger is something other than light itself.

Hi Folks,

It's not so much that the diurnal rhythm is 'programmed in' but plants have their own clock in the form of a 'Circadian Oscillator'. And so, yet another scientific paper on this very topic:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6466001/

Now, this is all very well but what are the practical implications, if any, for we aquarists?

JPC
 

JoshP12

Member
Joined
8 Dec 2019
Messages
471
Location
Canada
Now, this is all very well but what are the practical implications, if any, for we aquarists?

JPC

I think that placing our aquariums in the sun is the answer! :p:p

On a more serious note, if there is no negative impact on growth and we keep our photoperiod is within their awake part of the cycle, we are good.

I just saw dramatic opening down of leaves chasing for light and thought I was causing bizarre growth; it has to be because of my window that lets in a tiny bit of light in the AM. They did “correct” themselves within four hours or so, however.

And actually, a true complete darkness period is probably extremely beneficial.

Josh
 

JoshP12

Member
Joined
8 Dec 2019
Messages
471
Location
Canada
Well ... let’s give this a try:

I’ve been watching my macandra more closely and on the weekends when I am home (and we open that basement window), they curve towards the light (then curve back).

I wonder if I can see any difference in the latter.

The dramatic stuff I had mentioned before kind of stopped - not sure why. Probably just adjusted to my photoperiod.

Josh
 

Attachments

  • 0C404269-D507-47DA-AB86-210F94865B1B.jpeg
    0C404269-D507-47DA-AB86-210F94865B1B.jpeg
    1.6 MB · Views: 4
Top