Water relations in Norway spruce trees growing at ambient and elevated CO2 concentrations

Water relations were studied in Norway spruce [Picea abies (L.) Karst.] trees grown at ambient (AC, 350 mu mol mol(-1)) and elevated (EC, 700 mu mol mol(-1)) CO2 concentrations under temperate water stress. The results suggested that both crown position and variability in atmospheric CO2 concentration are responsible for different patterns of crown water relations. Mean hourly sap flux density (FSA) showed higher values in upper crown position in comparison with the whole crown in both AC and EC treatments. Mean soil-to-leaf hydraulic conductance (G(Tsa)) was 1.4 times higher for the upper crown than that calculated across the whole crown for the trees in AC. However, G(Tsa) did not vary significantly with crown position in EC trees, suggesting that elevated CO2 may mitigate differences in hydraulic supply for different canopy layers. The trees in EC treatment exhibited significantly higher values of F-SA measured on the whole crown level and slightly higher soil water content compared to AC treatment, suggesting more economical use of soil water and therefore an advantage under water-limited conditions

Aromatic Plants: use and nutraceutical properties

In the last years it has progressively been observed a substantial increase in the use of aromatic herbs and essential oils. Mediterranean area represents a particular environment in which many constraint factors (high light, temperature, drought, salinity, air pollution, etc.) induce a wide range of secondary metabolites in plants. These compounds can be useful utilized by humans for different applications: antibiotics, antimycotic, animal nutrition, cosmetics, food additives, biorepellents, etc. This paper reviews the literature on recent agro-industrial applications of Mediterranean plant species and medicinal plants used for the treatment of infectious diseases. The review includes accounts of extracts, essential oils and other active principles isolated from plants that have been used by folk medicine as antimicrobial agents. The name and part of the studied plants, spectrum of activity, type of active compounds and methods used are discussed and their mechanisms of action as well