Lamiaceae is one of the largest families of aromatic plants and it is characterized by the presence of external glandular structures which produce essential oils highly valued in cosmetics and medicine. Plants of Lavandula latifolia, Mentha piperita, Salvia sclarea, Salvia lavandulifolia, Thymus capitatus, and Thymus mastichina were grown for one year. In order to evaluate the effects of drought stress, plants were subjected to two water treatments (100% ETo and 70% ETo, including the rainfall during the experimental period). At the end of the experiment, the biomass, the essential oil content, and leaf nutrients concentration were assessed for each water treatment and species studied. At the end of the experiment, L. latifolia, M. piperita and T. capitatus plants showed a significant fresh weight reduction under drought stress conditions whereas the other species studied remained unchanged. With respect to dry weight, only L. latifolia plants showed a reduction under water deficit conditions. As far as essential oil content was concerned, L. latifolia and S. sclarea plants had a reduction under water deficit conditions. Leaf nutrient concentration showed different trends between species considering the nutrient assessed. The economic viability of the growth of this species will be dependent on the benefits achieved which are related to yield production obtained and the price accorded for both raw material and the essential oil extracted.

The blending of drainage with water of low electrical conductivity and the sequential reuse of the drainage water are innovative technologies to manage salts in agricultural drainage. Plants of Cucumis melo were grown in coir grow bags, and Rosmarinus officinalis and Cacti spp. were grown in pots with a mixture of sphagnum peat-moss and perlite. In order to assess the effect and evolution over time of these water treatments on plant growth and water management and removal of nutrients, three water treatments were applied over a period of eight weeks. These were: (1) standard nutrient solution; (2) blended water treatment (drainage water blended with water of low electrical conductivity (EC)) and (3) sequential reuse of drainage water treatment. During the experimental growing period, samples of water supplies and drainages generated in each water treatment were collected weekly and from these data water volume and nutrient loads were calculated. At the end of the experiment, leaf fresh weight of rosemary plants decreased under the fertigation with the blended and sequential reuse water treatments. Nevertheless, the application of blended and sequentially reused water allowed for the saving of significant amounts of water and nutrients in comparison to the standard nutrient solution treatment. Considering these advantages, we strongly recommend the setting-up of these water treatments in areas with water scarcity such as in the Mediterranean Basin.

We evaluated two osmotic adjustment substances (glycine betaine (GB) and glycine (G) and a combination of both glycine + glycine betaine (G + GB) using two modes of application; irrigation and foliar sprays with Dracaena sanderiana plants. The plants were grown in containers and subjected to two levels of NaCl concentrations (2.0 and 7.5 dS m⁻¹) over 8 weeks. Growth, pigment concentrations, and physiological parameters were assessed at the end of the trial. The foliar application of GB resulted in most optimal plant growth and biomass production in the presence of NaCl. The chlorophyll and carotenoid concentrations showed different trends depending on the osmotic adjustment substance applied and the mode of application. Stomatal density and dimensions varied considerably with respect to the osmotic adjustment substance supplied. The concentration of soluble sugars in leaves did not show a clear trend under the different treatments assessed. The exogenous application of G resulted in the highest concentration of free proline and proteins in leaves. The antioxidant capacity in leaves increased with both osmotic adjustment substances, and both means of application, under low and high saline conditions. We concluded that the foliar application of GB can be recommended in order to achieve cost-effective growth of D. sanderiana under saline conditions.

Sarcocornia fruticosa (L.) A.J. Scott is a dicotyledonous halophyte that grows in areas with an arid climate such as the marshes of southern Spain. The species has potential uses for saline agriculture and biofuel production, but the effects of salt stress on its nutrition and physiology remain unclear. Plants of S. fruticosa were grown in pots with a mixture of sphagnum peat-moss and Perlite. In order to evaluate the effects of different levels of salinity, five treatments using different NaCl concentrations (10 (control), 60, 100, 200 and 300 mM NaCl) were applied over a period of 60 days. At the end of the experiment, the dry weight, the biomass allocation and the tissue water content were measured for each salinity treatment. The net uptake of various nutrients and their translocation rates were calculated for each salt treatment. Salt loss, shedding of plant parts and succulence in shoots were evaluated together with the K+/Na+ ratio, K-Na selectivity, concentrations of osmolytes and their estimated contributions to the osmotic potential. Our results showed that S. fruticosa can maintain its major physiological processes at 60 mM NaCl without significant dry weight reduction. Higher salinity resulted in negative values for net uptake and translocation rates from roots to shoots of N and P. As might be predicted from other dicotyledonous halophytes, S. fruticosa plants increased Cl– and Na+ uptake using both as osmotica instead of organic osmolytes. However, to survive salinity, this species has also evolved others mechanisms such as shedding old shoots, increased succulence in shoots at higher salt concentrations and the ability to maintain a lower K+/Na+ ratio and higher K-Na selectivity in all organs.