The role of cover crops in irrigated systems: Soil salinity and salt leaching

Soil salinity and salt leaching are a risk for sustainable agricultural production in many irrigated areas. This study was conducted over 3.5 years to determine how replacing the usual winter fallow with a cover crop (CC) affects soil salt accumulation and salt leaching in irrigated systems. Treatments studied during the period between summer crops were: barley (Hordeum vulgare L.), vetch (Vicia villosa L.) and fallow. Soil water content was monitored daily to a depth of 1.3 m and used with the numerical model WAVE to calculate drainage. Electrical conductivity (EC) was measured in soil solutions periodically, and in the soil saturated paste extracts before sowing CC and maize. Salt leaching was calculated multiplying drainage by total dissolved salts in the soil solution, and use to obtain a salt balance. Total salt leaching over the four winter fallow periods was 26 Mg ha−1, whereas less than 18 Mg ha−1 in the presence of a CC. Periods of salt gain occurred more often in the CC than in the fallow. By the end of the experiment, net salt losses occurred in all treatments, owing to occasional periods of heavy rainfall. The CC were more prone than the fallow to reduce soil salt accumulation during the early growth stages of the subsequent cash crop

A new class of glycomimetic drugs to prevent free fatty acid-induced endothelial dysfunction

Background: Carbohydrates play a major role in cell signaling in many biological processes. We have developed a set of glycomimetic drugs that mimic the structure of carbohydrates and represent a novel source of therapeutics for endothelial dysfunction, a key initiating factor in cardiovascular complications. Purpose: Our objective was to determine the protective effects of small molecule glycomimetics against free fatty acid­induced endothelial dysfunction, focusing on nitric oxide (NO) and oxidative stress pathways. Methods: Four glycomimetics were synthesized by the stepwise transformation of 2,5­dihydroxybenzoic acid to a range of 2,5­substituted benzoic acid derivatives, incorporating the key sulfate groups to mimic the interactions of heparan sulfate. Endothelial function was assessed using acetylcholine­induced, endotheliumdependent relaxation in mouse thoracic aortic rings using wire myography. Human umbilical vein endothelial cell (HUVEC) behavior was evaluated in the presence or absence of the free fatty acid, palmitate, with or without glycomimetics (1µM). DAF­2 and H2DCF­DA assays were used to determine nitric oxide (NO) and reactive oxygen species (ROS) production, respectively. Lipid peroxidation colorimetric and antioxidant enzyme activity assays were also carried out. RT­PCR and western blotting were utilized to measure Akt, eNOS, Nrf­2, NQO­1 and HO­1 expression. Results: Ex vivo endothelium­dependent relaxation was significantly improved by the glycomimetics under palmitate­induced oxidative stress. In vitro studies showed that the glycomimetics protected HUVECs against the palmitate­induced oxidative stress and enhanced NO production. We demonstrate that the protective effects of pre­incubation with glycomimetics occurred via upregulation of Akt/eNOS signaling, activation of the Nrf2/ARE pathway, and suppression of ROS­induced lipid peroxidation. Conclusion: We have developed a novel set of small molecule glycomimetics that protect against free fatty acidinduced endothelial dysfunction and thus, represent a new category of therapeutic drugs to target endothelial damage, the first line of defense against cardiovascular disease

New trends for reference evapotranspiration and climatic water deficit

The paper deals with the trend for Penman- Monteith reference evapotranspiration and climatic water deficit during the first decade of the 21st century in Southern Romania vs the 20th century. For the first half of the year the monthly evapotranspiration values were higher for the first decade of the 21st century vs the means of the 20th century. However, the trend reverses for the second half of the year, but for the whole year the totals were higher for the first decade of the 21st century vs the totals of the 20th century. The yearly temperature means in the first decade of the XXI century showed an increase in the three locations studied, respectively, vs century XX. This warming is responsible to a great extent for the increase in evapotranspiration, and the relationship between evapotranspiration and temperature was highly significant. Water deficit decreased in Constanta and Pitesti, but there was a slight increase in water deficit in the same period in Bucharest-Baneasa. Water deficit increased in the first half of the year and decreased in the second half during the first decade of century XXI in all the three locations investigated vs century XX

New trends for reference evapotranspiration and climatic water deficit

The paper deals with the trend for Penman- Monteith reference evapotranspiration and climatic water deficit during the first decade of the 21st century in Southern Romania vs the 20th century. For the first half of the year the monthly evapotranspiration values were higher for the first decade of the 21st century vs the means of the 20th century. However, the trend reverses for the second half of the year, but for the whole year the totals were higher for the first decade of the 21st century vs the totals of the 20th century. The yearly temperature means in the first decade of the XXI century showed an increase in the three locations studied, respectively, vs century XX. This warming is responsible to a great extent for the increase in evapotranspiration, and the relationship between evapotranspiration and temperature was highly significant. Water deficit decreased in Constanta and Pitesti, but there was a slight increase in water deficit in the same period in Bucharest-Baneasa. Water deficit increased in the first half of the year and decreased in the second half during the first decade of century XXI in all the three locations investigated vs century XX