This study examines the composition of oils extracted from young olive trees of the Arbequina and Empeltre varieties grown with irrigation in the same farm throughout a period of three seasons. Quality parameters, Fatty acid composition, sterols, waxes and aliphatic alcohols were analyzed. Although the quality of oils of both varieties was that of extra virgin, varietal differences were found. The peroxide value and the content of total polyphenols were much higher in Empeltre, whereas stability was higher in Arbequina. The monounsaturated acids were higher in Arbequina containing more stearic, oleic, arachidic and behenic acids than Empeltre, while this variety surpassed Arbequina in palmitic, margaroleic, linoleic, linolenic, gadoleic and lignoceric acids. The sterol composition was also different in the two varieties with higher contents of 24-methylencholesterol, campesterol and, especially, Δ-5 avenasterol in Arbequina, and campestanol, Δ-7 stigmastenol, Δ-7 Avenasterol in Empeltre. The contents of both waxes and aliphatic alcohols were higher in Arbequina.

Este trabajo analiza la composición de aceites de árboles jóvenes de las variedades Arbequina y Empeltre cultivados en regadío en una misma finca. Durante tres campañas se estudiaron los parámetros de calidad, la composición en ácidos grasos, los esteroles, las ceras y los alcoholes alifáticos. Aunque la calidad de los aceites de las dos variedades fue la de virgen extra se encontraron diferencias varietales. El índice de peróxidos y los polifenoles totales tuvieron valores muy superiores en la variedad Empeltre, sin embargo la estabilidad fue mayor en Arbequina. El total de ácidos monoinsaturados fue mayor en Arbequina y el de poliinsaturados en Empeltre. Arbequina contenía más esteárico, oleico, araquídico y behénico que Empeltre, en tanto que en esta variedad era mayor en palmítico, margaroleico, linoleico, linolénico, gadoleico y lignocérico. La composición esterólica fue también diferente en las dos variedades, con mayores contenidos de 24-metilencolesterol, campesterol y, especialmente en Δ-5 Avenasterol en Arbequina, y de campestanol, Δ-7 Estigmastenol, Δ-7 Avenasterol en Empeltre. Tanto el contenido en ceras como el de alcoholes alifáticos fueron mayores en Arbequina

Unproductive saline and waterlogged (WT) wastelands could be beneficially transformed into agroforestry systems using trees tolerant to these stresses. We studied the salinity and waterlogging tolerance of five Australian tree species (Acacia salicina, Casuarina glauca, Casuarina obesa, Eucalyptus camaldulensis and Eucalyptus occidentalis) during seedling stage and their relationships with root and leaf ion concentrations. 8-month old plants were exposed for 5 months to five irrigation water salinity treatments (EC values between 2 and 22 dS m−1) and two waterlogging treatments (drained or WT). The salinity tolerance of the five species was high, although decreased in WT conditions. Irrespective of salinity, the two Casuarina species were more tolerant and the other three species were less tolerant to WT than drained conditions. In all species, salinity and waterlogging increased leaf Cl− and Na+ and decreased leaf Ca2+, but not leaf K+. Root Cl− and Na+ increased with salinity but not with waterlogging. Salinity tolerance was negatively correlated with Cl− and Na+ leaf accumulation rates per unit increase in salinity. Waterlogging reduced the ability of the seedlings to exclude Cl− and Na+ from the leaves. The two most salt tolerant Casuarina species under both drained and WT conditions showed the highest leaf Cl− and Na+ exclusion and the highest root Cl− and Na+ accumulation, suggesting that sequestration of these toxic ions in their roots was a significant salt-tolerant mechanism. Revegetation of saline and WT wastelands with these tolerant Casuarina species could be profitably used for biomass, biofuel and renewable energy production

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A field experiment was conducted for five years to study the response of 6-year old lemon trees cv. Verna on three different rootstock (sour orange, Cleopatra mandarin and macrophylla) to uniform applications of four irrigation waters having C1-concentrations of 4 (control), 11, 26.5 and 42.5 mol m-3, respectively.Fruit yield and the growth in trunk circumference were significantly reduced by increasing salinity in the rootzone, although this effect varied with the rootstock. The threshold values for response were 1.53, 2.08 and 1.02 dS m-1 for sour orange, Cleopatra mandarin and macrophylla respectively. The corresponding yield reduction for each unit increase in salinity above those values was 10.5, 13.7 and 14.2%, respectively. Trees on macrophylla accumulated higher C1-concentrations in the leaves than those from the other two rootstocks. The role of the interstock of sanguina orange on restriction of C1 uptake is discussed.The citrus growing area in Spain is located along the Mediterranean sea, with about 64% of water available having chloride concentrations higher than 10 mol m-3 (Martinez et al. 1987). Citrus response to salinity depends on several factors, such as rootstock-scion combination, irrigation system, soil type and climate, and changing some of these factors with the same irrigation water could produce entirely different results. Thus long-term experiments (Heller et al. 1973;Bingham et al. 1974;Shalhevet et al. 1974;Bielorai et al. 1978; Francois and Clark 1980;Cole 1985;Bielorai et al. 1988) have established that the salt tolerance of grapefruit and orange trees on different rootstocks differs.However, to the author's knowledge there is no published information pertaining to long-term effects of salinity on the fruit yield of lemon trees. Thus the objective of this 5-year field experiment was to study the response of lemon trees cv. Verna budded on three different rootstocks to four water qualities by measuring soil salinity, fruit yield and leaf chloride uptake. Offprint requests to: A. Cerda Materials and methodsThe Experimental Research Farm is located at 38~ 2~ with climatic conditions characterized by the following values averaged for the 1985-1989 period: rainfall 455 mm, air temperature 18~ relative humidity 65% and Class A pan evaporation 1751 mm.The experiment was carried out on a deep stony soil with calcium carbonate content of 550 g kg-i, classified as a Paralithic-mollic-calciorthid with a non-uniform profile having a bulk density and a volumetric water content at a matric potential of -0.03 MPa in the 0-0.5 m layer of 1.36 Mgm -3 and 0.27 m 3 m -3 respectively. The corresponding values in the 0.5-1.20 m layer were 1.41 Mg m-3 and 0.23 m 3 m-3 respectively.Uniform seedlings of sour orange, Cleopatra mandarin and macrophylla rootstocks were transplanted from a nursery to the experimental site in June 1976. After two years, macrophylla seedlings were budded with Verna lemon scions, whereas sour orange and Cleopatra mandarin were budded with sanguina orange scions (frost nucellar sel...