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- Lavandula multifida response to salinity: Growth, nutrient uptake, and physiological changesPublication . Garcia-Caparros, Pedro; Llanderal, Alfonso; Pestana, Maribela; Correia, Pedro José; Teresa Lao, MariaFern leaf lavender (Lavandula multifida L.) is a perennial shrub native to Almeria with known medicinal properties, which grows in saline soils that are increasingly present in the Mediterranean region. However, the effects of salinity on the mineral nutrition and physiology of L. multifida are unknown. In the present study, we evaluated the salt resistance of this species and compared it with other members of the Lamiaceae. Plants of L. multifida were grown in pots in a mixture of sphagnum peat-moss and Perlite, and treated with five different NaCl concentrations [10 (control), 30, 60, 100, and 200 mM NaCl] over a period of 60 d. The effects of different levels of salinity on mineral nutrient and osmolyte concentrations and on biomass were evaluated. Our results show that L. multifida plants were able to grow with 60 mM NaCl without significant biomass reduction. Na+ and Cl- were the main contributors to the osmotic potential in both roots and leaves, whereas total soluble sugars (TSS) and proline made only a small contribution. The concentrations of TSS and proline showed different trends in the different organs: in roots, both showed the highest concentrations at 60 mM NaCl, whereas in leaves TSS increased and proline decreased with increasing salt stress. To survive salinity, L. multifida plants increased salt excretion (Na+ and Cl-) by leaves at 100 and 200 mM NaCl and leaf succulence at 60, 100, and 200 mM NaCl. Excessive accumulation of Na+ and Cl- was avoided by shedding leaves. Our results indicate that L. multifida is better adapted to salinity compared to other members of the Lamiaceael, a consideration that is particularly relevant for their growth in and saline areas.
- Evaluation of carob tree productivity during a 30-year period, in relation to precipitation and air temperaturePublication . Correia, Pedro José; Cota, Tania; Pestana, MaribelaWater availability for irrigation of intensive crops will become a major problem in southern Iberia. One of the tools to sustain land use under water shortage is to choose crops well adapted to those environmental stress conditions featuring low water demand. The aim of this paper is to explore several relationships between climatic variables and the fruit production of carob-tree (yield) in a series of 30 consecutive years (1985-2015) referred to one single orchard. Precipitation and air temperature were the selected variables and regression models were tested. It was not possible to find any relations between yield and temperature, but precipitation during the hydrological year was inversely and significantly related to yield (Model 1- R-2 = 0.18). A close analysis indicated that rainfall registered during autumn was particularly effective, since higher yields were obtained in the years with less rainfall registered in the period September + October + November (SON) (Model 2; R-2 = 0.21). Although the air temperature effect was not found significant, mean values between 22.0 and 24.5 degrees C during SON were crucial to flowering and yield. Model 2 was validated using an independent data set considering 3 years, and the calculated yields were overestimated by 18.6% and 4.0% in two consecutive seasons. Moreover, Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios predict a precipitation decrease for SON period in the region, which may create favorable conditions for insect pollination and fruiting success.