Tropicals & Tender Perennials: Alocasia's in full sun, 1 by Alocasiaaddict

Alocasiaaddict wrote:
Julie, Thats an easy question LOL. Here goes: In 1986 the effect of fluoride at different concentrations was studied on the incorporation of ammino acid into extractable pigments (chlorophyll and pheophytin ) in tobacco leaves. Fluoride at concentrations of 10 PPM (parts per million) to 15 PPM inhibited the incorporation of ammino acids into chlorophyll. At 10 PPM the effect of fluoride on ammino acid incorporation was greater than that of chloride. The inhibition on formation of cell walls by fluoride was similar to that found on chlorophyll indicating an effect on synthesis of chlorophyll rather than degradation. The effect of fluoride on individual enzymes in the chlorophyll biosynthetic pathway is discussed in terms of relation to the action of fluoride on cellular ultrastructure.

So, in a nutshell, Flouride is an inhibitor but Chlorine actually bursts the cell walls of chlorophyll and is more dangerous to plants than Flouride because it requires less PPM (parts per million) to cause damage to the cell wall of chlorophyll. Discolored leaves is usually the first visable signs of chlorine poisoning.

The iron question: Iron benefits carotenoid and lutein which in turn acts as an antioxidant that protect pigment levels. So that may actually be good for your plants.