Factors Affecting Concentrations of Dimethylated Indolealkylamines in Phalaris Tuberosa L.

Abstract

In an experiment conducted in controlled-environment rooms, factors (temperature, light intensity, and nitrate supply) that influenced nitrate nitrogen concentrations in Phalaris tuberosa also affected concentrations of tryptamine alkaloids. Concentrations and yields of tryptamine alkaloids increased with higher day-night temperature regimes in both full sunlight and shade (28% sunlight); concentrations also increased with nitrate supply in full light but not in shade. Shaded plants had higher concentrations of alkaloids than unshaded plants at all levels of nitrate supply. Except for a difference between trends with levels of nitrate supply at 8 and 16 hr light, alkaloid concentrations were not affected by day length. In field-grown plants dimethyltryptamine, 5-methyoxydimethyltrypt-amine, and 5-hydroxydimethyltryptamine responded similarly to reductions in light intensity, the former being the dominant indole alkyl-amine in plants grown in the field and in the phytotron.