Genetic diversity of ICARDA’s worldwide barley landrace collection

Twenty genic- and genomic SSR markers were used to study genetic diversity and geographical differentiation of barley from 29 countries through analysis of a worldwide collection of 304 ICARDA’s barley landraces. Of these, 19 loci were highly polymorphic in the material studied. Based on Nei-distance matrix, Principal Component Analysis (PCoA) and cluster analysis using UPGMA associated with AMOVA the data revealed countries’ grouping within regions. Three distinct germplasm pools were identified in the landraces. The first of these was from Eastern Africa (Eritrea and Ethiopia) and South America (Ecuador, Peru and Chile) suggesting that barley introduced to South America might have originated specifically from East Africa or that they share a common genetic basis for adaptation. The second was the Caucasus (Armenia and Georgia) and the third included the remaining regions of Central Asia, Near East, Northern Africa and Eastern Asia. Genetic diversity of barley subspecies (Six-rowed barley, Two-rowed barley, H. spontaneum C. Koch and H. agriocrithon Åberg) also discriminates them into three groups: cultivated barleys (Six-rowed barley and Two-rowed barley), wild barley H. spontaneum and subspecies H. agriocrithon. These results associated with parsimony analysis demonstrate that H. agriocrithon and H. spontaneum might be distinct and do not support a hybrid origin for H. agriocrithon suggesting further investigation of the basis of more intense sampling of the two subspecies H. spontaneum and H. agriocrithon.     

Are changes in membrane lipids and fatty acid composition related to salt‐stress resistance in wild and cultivated barley?

The possibility to use membrane‐lipid measurements to screen barley genotypes for salt resistance was studied. The results showed that wild barley (Hordeum maritimum) displayed a typical halophytic response as compared to cultivated barley (Hordeum vulgare L. cv. Manel). Growth, tissue hydration, and photosynthetic activity were less affected by salinity in H. maritimum than in H. vulgare. The induced effects of long‐term NaCl treatment were reflected in root membrane lipids that remained relatively unchanged in wild barley, whilst they were significantly diminished with increasing salinity in H. vulgare. The levels of membrane‐lipid peroxidation and electrolyte leakage were changed only at high salt concentrations in H. maritimum whereas those of H. vulgare were considerably increased by lower salinity levels as a result of oxidative damage. These findings indicate that maintained membrane integrity (in H. Maritimum) may be considered a possible trait for salt resistance. However, membrane fluidity in H. vulgare was more increased than in H. maritimum. Thus, the unsaturated–to–saturated fatty acid ratio (UFAs : SFAs) and the double‐bond index (DBI), significantly increased in response to salt stress in cultivated barley while it did not change in H. maritimum. The changes in lipid unsaturation were predominantly due to increases in linolenic (C_18:3), linoleic (C_18:2), and oleic (C_18:1) acids and decreases in stearic acid (C_18:0). These results suggest that, in spite of being important for maintenance of membrane fluidity, the ability to increase unsaturation is not a determinant factor for salt resistance in barley species.     

Combined effects of salinity and phosphorus availability on growth,gas exchange,and nutrient status of Catapodium rigidum

The combined effects of NaCl-salinity and phosphorus deficiency on biomass production, nutritional status, and photosynthetic activity were studied in Catapodium rigidum: an annual Poacea with fodder potential. Plants were grown in hydroponic conditions for 55 days under two phosphorus (P) supply: 5 (low) or 180?µmol KH₂PO₄ (sufficient), in the absence or presence of 100?mM NaCl. Obtained results demonstrated that both salinity and P deficiency treatments applied separately reduced substantially plant growth and CO₂ assimilation rate with a more marked impact of salt stress. Salinity has no substantial effect on both shoot P concentrations and phosphorus acquisition efficiency independently of P availability. The highest decrease in plant growth (?91%) was observed in plants simultaneously submitted to both stresses suggesting an additive effect of the two stresses and that P deficiency increased the susceptibility of C. rigidum to salinity. This may be linked to a significant decrease in potassium acquisition (?95%), K/Na selectivity ratio (?73%), stomatal conductance (?66%), CO₂ assimilation rate (?64%), and shoot water content (66%). Furthermore, plants cultivated under combined salinity and sufficient P supply displayed higher stomatal conductance, CO₂ assimilation rate, K/Na selectivity ratio, and plant growth than plants cultivated under combined effects of salinity and P deficiency. These results suggest that adding P to saline soils could be an alternative for alleviating the negative effects of salinity and may ameliorate salinity tolerance.     

Variation in essential oil and fatty acid composition in different organs of cultivated and growing wild Ruta chalepensis L.

The essential oil and fatty acid composition of two provenances of Ruta chalepensis from four organs (leaves, flowers, stems and fruits) was determined. The effect of the plant part on total fatty acid contents, essential oil yields, fatty acid and volatile constituents was significant.Fatty acid profiles varied significantly among the studied provenances and organs. Linolenic acid had the highest amount in leaves of the two provenances. From R. chalepensis, in all organs, the main fatty acids were palmitic (13.10-25.31%), followed by palmitoleic (0-15.72%), stearic (1.03-6.85%), oleic (1.90-24.04%), arachidic (0.11-4.03%), eicosatetraenoic (0.10-5.60%) and behenic (0.47-6.09%) acids. Saturated fatty acids had the highest amounts in growing wild R. chalepensis flowers, and cultivated R. chalepensis stems were characterized by the predominance of polyunsaturated fatty acids. Oil composition of all studied organs has a healthy and nutritionally value. Essential oil yields varied from 0.39% to 2.46% and showed a remarkable variation with plant organs. Thirty-six volatile compounds were identified in different analyzed essential oils; 2-undecanone, 2-nonanol and 2-dodecanone had the highest percentages.     

Bioactive Compounds and Pharmacological Potential of Pomegranate (Punica granatum) Seeds - A Review

Plant Foods for Human Nutrition - The use of complementary medicine has recently increased in an attempt to find effective alternative therapies that reduce the adverse effects of drugs....     

Multiple element concentration in the grain of spring barley (Hordeum vulgare L.) collection

Multiple element analyses were carried out to investigate variation in element concentrations in barley grains of 336 genotypes. Of 13 elements analyzed, Ba ranged from 0.2 to 8.9?mg kg^?1, Ca from 186.4 to 977.5?mg kg^?1, Cu from 1.5 to 9.8?mg kg^?1, K from 353.2 to 7721.5?mg kg^?1, Mg from 1049.8 to 2024.2?mg kg^?1, Mn from 8.1 to 22.9?mg kg^?1, Na from 55.9 to 627.9?mg kg^?1, P from 2272.9 to 5428.8?mg kg^?1, S from 880.7 to 1898.0?mg kg^?1, Si from 19.1 to 663.2?mg kg^?1, and Sr from 0.35 to 2.62?mg kg^?1 in the barley grain. The least square means showed high Zn, Fe, Mg, P, and S concentration in AM-64 and AM-228 genotypes. The principal component analysis of element concentration showed four PCs explained 64.3% total variance. Strong positive correlations (p?<?0.001) of Fe-Mn, Fe-S, S-Mn, Zn-P, Zn-Mg, Mg-P, Mg-Mn, and Ca-Sr were found. The identification barley genotypes that showed high elements concentration furnish valuable genetic resources for biofortification in future.     

Salt effect on yield and composition of shoot essential oil and trichome morphology and density on leaves of Mentha pulegium

The aim of the present work was to study salt effect on the yield and composition of shoot essential oil (EO) and the structures responsible for its biosynthesis in Mentha pulegium L. Shoot EO was extracted by hydrodistillation and composition was determined by GC–MS method. Apical and basal leaves were taken for microscopy analyses; small fresh samples were observed directly without fixation or metallisation with environmental scanning electron microscope (ESEM) and stereomicroscope (SM). Fresh separate epidermis was used for light microscopy (LM). Salt stress enhanced EO yield by about 2.75 times and affected the percentage of menthone, which is the major compound (51%), increasing that of pulegone. Menthone, pulegone, and neomenthol constituting the monoterpene class were found to be the principal components. The anatomical study showed three types of trichomes: (i) non-glandular, multicellular, simple hairs; (ii) small, capitate glandular trichomes; (iii) and peltate glandular trichomes. In control plants, the density and size of trichomes varied with leaf side (abaxial or adaxial) and developmental stage. Salt stress results in significant modifications affecting trichome distribution and size on both sides.     

Nitrogen and NaCl salinity effects on the growth and nutrient acquisition of the grasses Aeluropus littoralis,Catapodium rigidum,and Brachypodium distachyum

Salinity and low nitrogen availability are important growth‐limiting factors for most plants. Our objective was to assess the influence of nitrogen (N) and salt levels on the growth and mineral nutrition of three forage grasses of varying salt resistance which are widely found in Tunisian salt lands, Aeluropus littoralis, Catapodium rigidum, and Brachypodium distachyum. Their response to salt and N interaction has not been studied and further investigations are necessary. Twenty day–old plantlets were hydroponically cultivated in Hewitt's nutrient solution. Half the plants were then exposed to 100 mM NaCl and the other half to no NaCl, and N was supplied at 0.5 or 5.0 mM N as NH₄NO₃. Plants were harvested after 60 d growth. Saline treatment (100 mM NaCl) decreased growth of B. distachyum (a relatively salt‐sensitive plant), but no significant effect was noted for A. littoralis (a relatively salt‐resistant plant) in both low– and high–N availability treatments. However, the effect of 100 mM NaCl on growth of C. rigidum (a moderately salt‐resistant plant) depended on N level. Increasing N availability and NaCl did not influence phosphate, sulfate, calcium, and magnesium concentrations in both A. littoralis and C. rigidum, but increased N supply reduced shoot sodium and chloride (Cl^–) accumulation. Potassium acquisition in A. littoralis and C. rigidum plants was severely depressed by increasing N availability under saline and nonsaline conditions, respectively. In these species, the increase of nitrate accumulation via N was attenuated by salinity. In contrast, total N content and allocation toward shoots were enhanced in these conditions, especially in A. littoralis, the most resistant species. It appears that increasing N availability at moderate salt levels has a beneficial effect on growth of species with high and moderate salt resistance, but not on species with low resistance to salinity.