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- Author or Editor: José Antonio Franco x
Lagurus ovatus is an annual grass typical of sandy coastal soils, wide-spread in southern Europe. The color and texture of the inflorescence have such features that give good qualities as dry flower. In this work we have studied the germination capacity of Lagurus ovatus in different conditions of temperature, light and salinity. Seeds harvested in of the province of Murcia (Southeast of Spain) were tested in germination chambers with constant temperatures (5, 10, 15, 20, 25 and 30 °C) and combined temperatures (20/30, 15/25, 10/20 and 5/15 °C). For each treatment, the photoperiod was 12 hours and total darkness. The results showed that total darkness was required to germination and the highest germination were obtained with constant temperatures of 10°C (90%) and 15°C (66%). Temperatures above or below reduced significantly the final germination. With alternate temperatures, the highest values were recorded when at least for 12 hours the temperature was 10 °C or 15 °C (5/15, 10/20 and 15/25 °C) 87%, 93%, and 88% respectively. Once calculated the optimum temperature a salinity experiment was carried out to determine how this parameter affected germination. The assay was carried out at 10/20 °C. The seeds were watered with a NaCl2 solution of: 0, 2.5, 5, 7.5, 10, 12.5, 15 and 17.5 dS·m-1. The greatest germination was obtained in non-saline control (88%) and its was linearly reduced with increases in salinity to 10 dS·m-1 (4%). No germination was registered from 12.5 to 17.5 dS·m-1. When non-germinated seeds were transferred to distilled water after the exposure to salinity, rates of germination were very high in all cases. This work was supported by the CICyT of Spain (project AGL2000-0521).
The wild native vegetable cultivation in Spain is very interesting due to the potential value as leafy vegetable. In order to preserve the minor crop diversity we investigate several wild species as Silene vulgaris. This is a perennial herbs, widespread in Europe and North of Africa, very appreciated by leaf in the Iberian Peninsula. In this work, six fertilization treatments with different Base Fertilizer: Top Fertilizer were evaluated in the field on Mediterranean coast of Spain: T0 (without fertilization), T1 (5000 and 0), T2 (2500 and 725), T3 (2500 and 363), T4 (1250 and 725),T5 (1250 and 363), T6 (625 and 181) kg·ha-1, Base fertilized, and Top fertilizer respectively. Silene vulgaris seedlings 30 days old were transplanted to 1 m2 experimental plots under drip irrigation. and previously Base fertilized with Guano of fish (4% N, 8% P, 4% K). Thirty days later a Top fertilization were applied with KNO3 (13,8% N and 44% K). Two harvests were carried out 55 and 110 days after plantation and the parameters measured were the fresh mass and the dry mass. In the first harvest, both fresh and dry mass were significantly greater in T3 (8541 and 1522 kg·ha-1, respectively), while T0 produced the smallest yield (3765 and 625 kg/ha, respectively). In the second harvest, T4 produced the greatest values of fresh and dry mass (9995 and 903 kg·ha-1, respectively), while, again, T0 threw the smallest values (4846 and 464 kg·ha-1, respectively). This work was supported by the CICYT of Spain (Project AGL2000-0521) and by the Fundación Séneca of the Region of Murcia (project PI-27/00753/FS/01).
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.
Physiological and biochemical indicators that reflect the responses of plants to chilling stress could be useful for identifying plant damage caused by freezing or other stresses. The objective of this study was to determine any relationship between changes in chlorophyll fluorescence and the appearance of visual symptoms resulting from freezing temperatures in two cultivars of oleander. In the least frost-sensitive cultivar (yellow oleander), freezing temperatures (–4 °C for 3 h) did not produce changes in the photochemical parameters. In the more frost-sensitive cultivar (pink oleander), non-photochemical quenching (NPQ) and the maximum photochemical efficiency of photosystem II (Fv/Fm) decreased after the same freezing treatment. The first of these potential indicators remained low, whereas the second steadily recovered during the 4 months after freezing simulation. The results suggest that measuring chlorophyll fluorescence may provide a rapid method for assessing freezing injury in oleander.