Wong, Lynette Y. , Cohen, Jerry D. , Markhart, Albert .
Evidence for stress induced in vivo metabolic flux of 2-phenylethyl glucosinolate in Nasturtium officinale R. Br.
Incorporation of 2H from 2H2O into 2-phenylethyl glucosinolate (gluconasturtiin) found in Nasturtium officinale R. Br. (watercress) was used to assess temporal changes in the metabolite pool. Watercress was germinated and grown on 30% 2H2O. Mass spectral analysis was used to compare incorporation of 2H atoms into the non-exchangeable positions of the phenyl ring. Following the labeling period, 6.7% of the gluconasturtiin molecules synthesized in the presence of 2H2O were not labeled with deuterium. After 4 weeks further growth on unlabeled water, the percentage of unlabeled gluconasturtiin molecules increased to 26.3%, accounting for an increase of 19.6% in the amount of the unlabeled compound. Since the plants growth rate was such that the fresh weight increase during the labeling period was 23.3%, these data suggest that new synthesis is accounted for entirely by that required for new growth. This provides evidence for very low degradation rates of gluconasturtiin in vivo. The accumulation of unlabeled gluconasturtiin suggests that the 49% increase of gluconasturtiin due to water deficit, shown in a previous study, was caused by greater de novo synthesis.
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1 - University of Minnesota, Horticultural Science, Alderman Hall, 1970 Folwell Ave, Saint Paul, MN, 55108, U.S.A.
2 - University of Minnesota, Horticultural Science
Plant secondary metabolism
Presentation Type: Plant Biology Abstract
Location: Exhibit Hall (Northeast, Southwest & Southeast)/Hilton
Date: Sunday, July 8th, 2007
Time: 8:00 AM