Salvinia increased the pH of the growth media within two days to near neutral pH in the absence of Al with and without humic substances. In most cases, Al in the absence of humic substances reduced salvinia growth, chlorophyll a and b concentrations, and carotenoid concentrations. Reductions were greater with increasing concentrations of Al and humic substances alleviated some of the toxic effects of Al. Also, corrected treatments (pH 3.9) influenced an increase in the above parameters for most treatments compared to uncorrected treatments (pH varied according to the treatment). Anthocyanin concentrations of salvinia increased in treatments receiving Al. The accumulation of soluble sugars, starch, and total nonstructural carbohydrates (TNC) increased in the presence of 20.0 mg/l Al without humic substances and decreased in treatments receiving humic substances.
Gardner, Jeffrey L. and Al-Hamdani, Safaa H., "Interactive Effects of Aluminum and Humic Substances on Salvinia" (1997). Research, Publications & Creative Work. 78.