Too much fluorescent light?

[DTEguy]

Originally Posted by Magnus A

The filtering effect by anthocyanins of the wavelengths used by photosynthesis is not very significant. But at those light levels the photosystem II (PSII) has inhibit itself, and it is then it get really sensitive for light radiation damage.

The scientific explanation is that the proton gradient over the thylakoid membrane, where PSII is located, get to high after a while and prevent the possibility for PSII to use water as an electron source.(Water can no longer be converted to oxygen) This happen in the northern hemisphere pine forests at about 10-11 am during a normal summer day.

I read that PSII system will be damaged regardless of the light intensity and is rapidly repaired. I was thinking even if the rate of damage is higher than rate of repair (in high light), the job is done and the photosynthesis yield would have been optimal (unless there are some irrerversible damage). However, photosynthesis rate was actually lower in a research on catts. in high light versus the one in intermediate light.

edit: Just read that excessive free radical oxygen from high light inhibit the repair mechanism. That makes sense now.

I guess the best thing to do is to use the reported fc as a guide and figure out that threshold. The tip that you gave me on how to observe the level of anthocyanin as you acclimatize it slowly will be very useful. Thanks.

---------- Post added at 12:21 AM ---------- Previous post was at 12:19 AM ----------

Originally Posted by isurus79

Under high light (or even moderate light, depending on the species) new growths will come out red or purple and then turn green once they "harden." This is another way to see if your green Catt is getting enough light, even though the adult growths are green and not red/purple.

Thanks for the tip!!