Interest in cultivating common purslane (Portulaca oleracea) as a food crop has grown since its identification as an exceptionally rich source of bioprotective substances considered essential for normal human growth, health promotion, and disease prevention. However, little is known about the suitable cultural systems, substrates, and irrigation systems for common purslane's commercial production. In this study, we examined the effects of various substrates in a floating system on common purslane's yield and fatty acid content during 2003 and 2004. We carried out three experiments using peat, vermiculite, coir, perlite, and mixtures of peat and perlite (3:1 and 1:1 v/v). In 2003, highest yields were obtained in plants grown in either peat (1806 g·m−2) or vermiculite (1982 g·m−2) and far exceeded those grown in coir (1254 g·m−2) or perlite (834 g·m−2). In 2004, plants grown in peat or 3 peat:1 perlite mixture yielded the best (2000 g·m−2), whereas the lowest yields were obtained in plants grown in either coir or perlite (534 and 601 g·m−2, respectively). Plants grown in peat substrate had the highest total fatty acid content, alpha-linolenic acid, and linoleic acid, whereas the highest proportion of alpha-linolenic acid to total fatty acids was obtained in plants when grown in either coir or perlite.
Víctor Cros, Juan José Martínez-Sánchez and José Antonio Franco
José A. Franco, Víctor Cros, Sebastián Bañón, Alberto González and José M. Abrisqueta
The influence of two irrigation treatments during nursery production on the post-transplant development of Lotus creticus subsp. cytisoides was studied. The treatments lasted 96 days and consisted of irrigating 2 days/week with a total of 2.3 L of water per plant over the whole nursery period (T-2) or irrigating six days per week with a total of 7 L of water per plant (T-6). T-2 plants had greater root length: shoot length ratio and higher percentage of brown roots, an indicator of more resistance to post-transplant stress. Minirhizotrons revealed more active root growth in the surface soil of the T-2 plants, although the plants of both treatments rapidly colonized the whole soil depth studied (0-160 cm deep). T-2 plants had greater stem length growth per unit of soil area covered.