title: The effect of temperature, photoperiod, and light quality on gluconasturtiin concentration in watercress (Nasturtium officinale R. Br.).
abstract: The effects of different growth regimes on gluconasturtiin concentration in watercress (Nasturtium officinale R. Br.) were investigated. Watercress plantlets at the 5th mature leaf stage (ca. 2 weeks old) were exposed to different day and night temperatures, to long (16 h) or short (8 h) days, to red (R) or far-red (FR) light given during the main long day photoperiod, and finally to R or FR light given at the end of the main photoperiod. Watercress plants grown under long days contained a 30-40% higher gluconasturtiin concentration and had a higher fresh weight than watercress plants grown under short days. Watercress plants grown under long days and temperatures of 15 or 10 degrees C had at least a 50% higher gluconasturtiin concentration, but a lower fresh weight, than that of plants grown at 20 or 25 degrees C. Watercress plants grown under metal halide light enriched with R light had approximately a 25-40% higher concentration of gluconasturtiin as compared to the FR-enriched plants. Likewise, a brief R light exposure at the end of the main photoperiod resulted in approximately a 25% or higher concentration of gluconasturtiin as compared to a FR end-of-day exposure. These data indicate that the concentration of gluconasturtiin in watercress can be significantly increased by growing plants at lower temperatures, under long days, and by exposure to R light.
authors.affiliation: Department of Horticultural Science, University of Minnesota, 1970 Folwell Avenue, 305 Alderman Hall, St. Paul, Minnesota 55108, USA.
authors.forename: Gerard
authors.initials: G
authors.lastname: Engelen-Eigles
authors.forename: Greg
authors.initials: G
authors.lastname: Holden
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Cohen
authors.forename: Gary
authors.initials: G
authors.lastname: Gardner
mesh_terms: D002851:Chromatography, High Pressure Liquid; D005961:Glucosinolates / Q000032:analysis*; D008027:Light; D031223:Nasturtium / Q000737:chemistry*; D017440:Photoperiod; D013696:Temperature
chemical_list: D005961:Glucosinolates; C443697:gluconasturtiin