I was looking into nute burn/deficiency and came across this from another site. I'm not sure if this has ever been posted here, if it has, sorry for the repost. If not, then perhaps it will help some ppl.
I didn't write or photograph any of the following and I give credit to whomever did:
Light movers are also beneficial to reduce light poisoning - constant intense light destroys the chloroplast, the solar panels of plants.
A cruel irony is that 12 hours of constant light from an HID actually reduces the percentage of light that the plants can absorb and convert to chemical energy to produce buds. A Light Rail not only doubles the space of our gardens it also gives the chloroplasts down time to distribute the chemical energy.