Tuesday, July 31, 2012
Grand Ballroom
Purslane (Portulace oleracea) is a succulent weedy annual in much of the United States. In other parts of the world, purslane is grown as a specialty vegetable crop and valued for its nutritional quality and high levels of omega-3 fatty acids. Nitrogen (N) will influence plant growth and alter pigment composition and accumulation. As a leafy vegetable crop, purslane contributes carotenoid phytochemicals in the typical “Mediterranean Diet”. However, little is known about the impact N fertility levels will have on pigment concentrations in purslane shoot tissues. The objective of this study was to evaluate the influence of N fertility levels on the concentration of nutritionally important carotenoid and chlorophyll pigments in purslane. Two cultitypes (‘green leaf’ and ‘yellow leaf’) of purslane were grown in nutrient solution culture under 13, 26, 52, or 105 mg·L-1 of N. Plants were harvested at 45 days after seeding, and tissue was freeze-dried for pigment analysis. Carotenoid and chlorophyll pigments were extracted from shoot tissues and measured using HPLC methods. Nitrogen level influenced shoot tissue beta-carotene (P = 0.02), lutein (P = 0.003), neoxanthin (P = 0.002), total carotenoids (P = 0.006), chlorophyll a (P = 0.001), chlorophyll b (P = 0.001), and total chlorophyll (P = 0.001) in purslane shoot tissues. Purslane cultitypes influenced concentrations of lutein (P = 0.001), neoxanthin (P = 0.001), violaxanthin (P = 0.002), chlorophyll b (P = 0.001), and total xanthophyll cycle pigments (P = 0.003). Increases in N fertility levels acted to increase concentrations of nutritionally important shoot tissue pigments in purslane. Therefore, N fertility management should be considered when using purslane as a specialty vegetable crop.