The Combined Effect of Mediterranean Shrubland Pasture and the Dietary Administration of Sage By-Products on the Antioxidant Status of Segureña Ewes and Lambs.

The objective of this study was to determine if the combined effect of ewe grazing and the incorporation of sage by-products in the lamb feed enhances the Segureña ewe and lamb antioxidant status. For that, the endogenous (related to blood antioxidant enzymes) and exogenous (plasma antioxidant activity) antioxidant systems of ewes and lambs were studied at the physiological stages of lactation, after weaning and at the end of the fattening period. Major results indicated that grazing improved the enzymatic antioxidant defense of ewes during the stressful period of lamb weaning, and also, the antioxidant status of the ewe plasma at both physiological stages: lactation and after lamb weaning. With regards to the lambs, ewe grazing stimulated the antioxidant enzymatic defense during lactation, but not the antioxidant capacity of the plasma. At the end of the fattening period, the inclusion of sage by-products in the lamb diet (10% w/w) enhanced both the enzymatic cascade and antioxidant capacity of the lamb plasma. The antioxidant capacity of the lamb meat was also studied and the benefits of sage were detected in samples from the deltoideus muscle. Thus, Mediterranean grazing stimulated the antioxidant defense in ewes, while the inclusion of sage by-products in the lamb diets enhanced the antioxidant status of both blood and meat.

Accumulation of furanocoumarins by Bituminaria bituminosa in relation to plant development and environmental stress.

Bituminaria bituminosa (L.) C.H. Stirton (Fabaceae) accumulates high concentrations of the furanocoumarins (FCs) angelicin and psoralen, which protect against infection and herbivory. The effects on FC accumulation of the exposure of two populations of B. bituminosa to abiotic stress (cold, heat and drought) under field conditions were determined, as well as the effect of temperature under controlled conditions, in hydroponic culture. In field conditions, psoralen and angelicin levels in the leaf dry matter were 400-6000 and 1500-11,000 µg g(-), respectively. There were significant effects of population on the psoralen concentration and psoralen:angelicin ratio. In hydroponic culture, exposure to a diurnal temperature of 33 °C increased FC levels in population Calnegre but not in Llano del Beal, compared with plants grown at 22 °C; however, high summer temperatures in the field (>30 °C) did not coincide with the highest leaf FC levels, since the plants accumulated FCs preferentially in the fruits. Hence, leaf FC levels were higher in winter. Irrigation, to alleviate water stress in the semi-arid conditions, increased the fruit psoralen concentration but produced only minor decreases in leaf FC levels. There was a significant, positive correlation (P < 0.001) between the FC and nitrogen concentrations in the plant organs analysed (both increased in the order: fruits > growing leaves > mature leaves), reflecting their respective contributions to plant fitness. The genetically- and developmentally-regulated accumulation of FCs by B. bituminosa is altered by short-term variations in environmental conditions, particularly temperature.

Physiological responses of Bituminaria bituminosa to heavy metals.

Two hydroponic experiments were performed to study the physiological responses to heavy metals (HMs) of two populations of Bituminaria bituminosa (L.) C.H. Stirton (Fabaceae): one ("C2") from a site contaminated by HMs and one from a non-contaminated site ("LA"). In the first, we studied the effects of elevated concentrations of Zn (12 and 61 µM). Population C2 was more tolerant in terms of root and shoot growth at 61 µM Zn, relative to control plants (1 µM Zn). The similar tissue Zn levels of the two populations suggest that C2 is more tolerant of high tissue Zn. Of the parameters measured that could be related to Zn phytotoxicity (micro and macronutrients, root hydraulic activity, water-extractable Zn and organic acids), none could explain totally the superior tolerance of C2. In the second assay, the effects of Cd (4.4 µM), Cu (7.8 µM) and Zn (76 µM) on plant accumulation of the furanocoumarins (FCs) psoralen and angelicin, which function as feeding deterrents and photo-activated toxins, were assessed. For population C2, all three HMs increased the root FC concentrations, while Cd also raised shoot levels. For LA, Cu raised the root concentrations of both FCs. There was a relationship between plant stress, manifested as proline accumulation and disruption of plant water relations, and increased FC accumulation. Higher tissue levels of FCs likely provide greater protection against bacterial or fungal infection and herbivores.