Photoinhibition, would it happen to the aquatic plants?

[paludarium]

Recently a botanist told me that under too much light photoinhibition will ensue and subsequently hurt the plants. He also mentioned the mechanism of photoprotection and photodamage, but for me those processes are tough to understand. However I would like to know will photoinhibition happen to the aquatic plants? And how much light is too much for the aquatic plants?

 

[Tom Barr]

Re: Photoinhibition, would it happen to the aquatic plants?

More than you can place oer a tank

Ex:

At 2" away from a 5.5 w/gal PC lighting, only 450 micromoles of light are measured, vs 600 or so for fully saturated light for 3 aquatic weeds.
So most are low light as full sun is about 2000.

But still a LONG way off from PI.
Most high light tanks are in the 200 range lower down and at the bottom, maybe 50-100.

Regards,
Tom Barr

 

[paludarium]

Re: Photoinhibition, would it happen to the aquatic plants?

Thanks for the answer. So it's the nutrition deficiency but not the high light that causes aquatic plants stunted.

I also find a interesting phenomenon, the stem plants tend to be creepy but not growing upright in a high light tank. IME, many aquatic plants bend their stems more horizontally when their heights have reached some distances beneath water level (or light). Could that be the way that the stem plants are trying to avoid too much light?

Regards,
Erich

 

[Tom Barr]

Re: Photoinhibition, would it happen to the aquatic plants?

Thanks for the answer. So it's the nutrition deficiency but not the high light that causes aquatic plants stunted.

Yes.

But more light => more CO2 demand and more CO2 => more nutrients.
As long as you limit light like we generally do, then providing ample CO2/nutrients works.

Basically you get the most out of your light.

I also find a interesting phenomenon, the stem plants tend to be creepy but not growing upright in a high light tank. IME, many aquatic plants bend their stems more horizontally when their heights have reached some distances beneath water level (or light). Could that be the way that the stem plants are trying to avoid too much light?

Regards,
Erich

No, something else is likely happening, CO2/nutrients.

Regards,
Tom Barr

 

[jerime]

Re: Photoinhibition, would it happen to the aquatic plants?

Tom, is there a time limit for the light to be on, in terms of damage to the plants?
I know that the preferred photoperiod is 10-12 hours, but if I wanted to light my tank at 4 wpg for 16 hrs., would that harm the plants in anyway?

 

[Tom Barr]

Re: Photoinhibition, would it happen to the aquatic plants?

Why do you want to toast plants for 16 hours?
If you are me, you may have certain questions you waqnt answered, but just for fun?
Stick with 10-11 hours.

They do not need that much and they also do not need so much light as many have these days. T5's are nice because they are reducing the total watts folks keep these days.

Regards,
Tom Barr

 

[jerime]

Re: Photoinhibition, would it happen to the aquatic plants?

Why do you want to toast plants for 16 hours?
If you are me, you may have certain questions you waqnt answered, but just for fun?

Not for fun (I'm not bored ). Purely for theoretical reasons. It's a question I'm interested in, in matter of inhibition of any sort.

I've seen some guys trying to maintain 24 hrs. lighting period, with no damage to the plants in the 1st few days.

Is there any real problem for the plants with that longer period or even 24 hrs. lighting cycle ?

 

[Tom Barr]

Re: Photoinhibition, would it happen to the aquatic plants?

Generally they will grow better with less light.
Algae has a distinct advantage to odd lighting routines.
You do get better growth and cycling with normal light routines.

Regards,
Tom Barr

 

[Cornhusker]

Re: Photoinhibition, would it happen to the aquatic plants?

tom,also when 3watts per gallon or less in high plant mass tanks,fish and plants look so much better inmo. and those ugly scratches in the glass don't show up as bad.regards,cornhusker

 

[Urkevitz]

Re: Photoinhibition, would it happen to the aquatic plants?

I have been using 2 shop lights with T-8 bulbs on my 75 gallon instead of my 260 watt aqualight. The plants are growing faster and look better, I am using DIY Co2 so less light is an advantage.

 

[Tom Barr]

Re: Photoinhibition, would it happen to the aquatic plants?

As you keep plants longer, you will see that more light is not better.

Neophytes believe otherwise.

Less light = less demand for CO2, and nutrients and allows the plants to develop the coloration better also(plant has more time to do so).

Regards,
Tom Barr