Poster: Secondary metabolism

Abs # 264: The effect of photoperiod, light quality, and temperature on 2-phenylethyl glucosinolate levels in watercress (Nasturtium officinale).

Presenter:	Engelen-Eigles, Gerard
Authors	Engelen-Eigles, Gerard  (B) (A)  Holden, Greg  (A)   Cohen, Jerry D (A)   Gardner, Gary  (A)
Affiliations:	(A): Department of Horticultural Science, University Of Minnesota (B): Present Address: BioProfile Testing Laboratories, LLC

Watercress (Nasturtium officinale R. BR.) is an abundant source of gluconasturtiin (2-phenylethyl glucosinolate). The hydrolysis product of gluconasturtiin, 2-phenylethyl isothiocyanate (PEITC), has been shown to prevent cancer in animal model systems. Watercress has traditionally been harvested from streams, but now it is increasingly field-grown or grown hydroponically in greenhouses. In this research, we investigated the effect of photoperiod and light quality on gluconasturtiin content in watercress. Watercress plants grown under long days contained higher gluconasturtiin content and higher fresh weight than watercress plants grown under short days. Watercress plants grown under metal halide light enriched with red (R) light had higher gluconasturtiin content compared to plants grown under a far-red (FR) -enriched light regime. Likewise, a brief R light exposure at the end of the main photoperiod resulted in higher gluconasturtiin content compared to a FR end-of-day exposure. A constant growth temperature of 15 C resulted in higher gluconasturtiin concentration compared to watercress growing under constant 25 C. In addition, when the night temperature was lower than the day temperature, gluconasturtiin concentration was increased compared to plants growing under constant 20 C. Thus, gluconasturtiin concentrations in watercress can be increased by alterations in environmental conditions under controlled growing environments. Supported by the SOTA TEC Fund and the Minnesota Agricultural Experiment Station.