Influence of nitrogen and sulfur on biomass production and carotenoid and glucosinolate concentrations in watercress (Nasturtium officinale R. Br.).
Watercress (Nasturtium officinale R. Br.) is a perennial herb rich in the secondary metabolites of glucosinolates and carotenoids. 2-phenethyl isothiocyanate, the predominate isothiocyanate hydrolysis product in watercress, can reduce carcinogen activation through inhibition of phase I enzymes and induction of phase II enzymes. Sulfur (S) and nitrogen (N) have been shown to influence concentrations of both glucosinolates and carotenoids in a variety of vegetable crops. Our research objectives were to determine how several levels of N and S fertility interact to affect watercress plant tissue biomass production, tissue C/N ratios, concentrations of plant pigments, and glucosinolate concentrations. Watercress was grown using nutrient solution culture under a three by three factorial arrangement, with three S (8, 16, and 32 mg/L) and three N (6, 56, and 106 mg/L) fertility concentrations. Watercress shoot tissue biomass, tissue %N, and tissue C/N ratios were influenced by N but were unaffected by changes in S concentrations or by the interaction of NxS. Tissue pigment concentrations of beta-carotene, lutein, 5,6-epoxylutein, neoxanthin, zeaxanthin, and the chlorophyll pigments responded to changes in N treatment concentrations but were unaffected by S concentrations or through N x S interactions. Watercress tissue concentrations of aromatic, indole, and total glucosinolate concentrations responded to changes in N treatments; whereas aliphatic, aromatic, and total glucosinolates responded to changes in S treatment concentrations. Individual glucosinolates of glucobrassicin, 4-methoxyglucobrassicin, and gluconasturriin responded to N fertility treatments, while gluconapin, glucobrassicin, and gluconasturiin responded to changes in S fertility concentrations. Increases in carotenoid and glucosinolate concentrations through fertility management would be expected to influence the nutritional value of watercress in human diets.
Kopsell
Dean A
DA
Plant Sciences Department, The University of Tennessee, Knoxville 37996, USA. dkopsell@utk.edu
Barickman
T Casey
TC
Sams
Carl E
CE
McElroy
J Scott
JS
D018533:Biomass; D002338:Carotenoids / Q000032:analysis*; D002734:Chlorophyll / Q000032:analysis; D005961:Glucosinolates / Q000032:analysis*; D031223:Nasturtium / Q000737:chemistry* / Q000187:drug effects* / Q000254:growth & development; D009584:Nitrogen / Q000494:pharmacology*; D013455:Sulfur / Q000494:pharmacology*
D005961:Glucosinolates; D002734:Chlorophyll; D002338:Carotenoids; D013455:Sulfur; D009584:Nitrogen