INTERACTIVE EFFECTS OF POLYLACTIC ACID WITH DIFFERENT ALUMINUM CONCENTRATIONS ON GROWTH, PIGMENT CONCENTRATIONS, AND CARBOHYDRATE ACCUMULATION OF AZOLLA

The interactive effects of 1 mu g l(-1) polylactic acid (PLA] with alu minum concentrations of 2, 4, 8, and 16 mg l(-1) on Azolla caroliniana growth, chlorophyll, carotenoid, anthocyanin, and carbohydrate accumu lation were examined. Azolla growth was decreased with increases in al uminum concentration. Furthermore, the growth reduction was less prono unced when PLA was present. Chlorophyll a and b concentrations were de creased in plants grown at Al concentrations of 4 mg l(-1) and higher. Polylactic acid reduced the influence of Al concentrations of 4, 8, a nd 16 mg l(-1) on chlorophyll a and b. Similarly, carotenoid concentra tions were decreased as Al concentrations increased in the growth medi a. Anthocyanin concentration was increased at 4.0 mg l(-1) Al without PLA and at higher Al concentrations with or without PLA. In general, c arbohydrate accumulation increased as Al concentration increased. Howe ver, this increase in carbohydrates was less pronounced in the presenc e of PLA. In the absence of Al from the growth media, treatment with 1 mu g l(-1) PLA resulted in an increase in plant growth, chlorophyll, and carotenoid concentration and a decrease in carbohydrate accumulati on.