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Drought, salinity and forest fires are adverse abiotic factors responsible for the failure of plant regeneration in the Mediterranean regions. The objective of this study was to evaluate Pinus pinea seed germination in response to heat, osmotic and salinity stress. Separate experiments were conducted, using polyethylene glycol (PEG) as an osmotic agent to reproduce drought stress, and sodium chloride (NaCl) and diluted seawater as salinizing agents to simulate salinity stress. Different temperatures were used to reproduce the effects of different fire regimes. Seed germination and the activities of the main enzymes involved in Pinus seed reserve utilization (glyoxylate cycle enzymes) decreased with increasing PEG, NaCl and seawater concentrations. Seawater appears to be the least toxic salinizing agent on Pinus pinea seed germination. The present study indicates that the germination of Pinus pinea seeds is influenced by the concentrations and even more by the nature and interactions of the ions present in the solutions. As regard heat treatments, the maximum germination percentage (80%) was obtained at 80°C and short exposure time (3 min). Increasing exposure time and temperature led to the germination percentage progressively decreasing.

BACKGROUND Red onion is popular in cuisines worldwide and is valued for its potential medicinal properties. Red onion is an important source of several phytonutrients such as flavonoids, thiosulfinates and other sulfur compounds, recognized as important elements of the diet. Nowadays, there is the need of producing food enriched in health benefit compounds. In this study, pads of sulfur bentonite (SB) with the addition of orange residue (OR) or olive pomace (OP) were used to improve the quality of red onion. The experiment was conducted for 3 months in the field to evaluate the phytochemicals of differently amended red onion. RESULTS Treated plants were better in quality than controls. Antioxidant activity, detected as DPPH, ORAC and ABTS, was highest in plants grown in the presence of SB enriched with agricultural wastes, particularly SB‐OR. Polyphenols increased in all treated plants. The volatile fraction was clearly dominated by sulfur compounds that are strictly related to the concentration of the aroma precursors S‐alkenyl cysteine sulfoxides. The greater amount of thiosulfinates in treated compared with untreated onion evidenced that SB pelletized with agricultural wastes can represent a new formulation of organic fertilizer able to improve the beneficial properties of onion. The results highlighted that the best red onion quality was obtained using SB‐OR pads. CONCLUSION The use of SB bound with agricultural wastes represents a novel strategy to increase bio‐compounds with beneficial effects on human health, to enhance the medical and economic values of sulfur‐loving crops, with important consequences on the bio and green economy. © 2019 Society of Chemical Industry

Changes in soil properties related to natural regeneration of silver fir (Abies alba, Mill.) in small (185 m 2 ) and medium (410 m 2 ) gaps, in the Calabria Apennines (Southern Italy), were studied 2 years after gap creation. The organic matter within the medium gaps decayed more rapidly than those in the small gaps. Among the microenvironmental variables and soil properties, soil temperature was most strongly positively related to organic matter decomposition rates. Medium gaps had high soil temperature and photosynthetically active radiation (PAR) transmittance, and low soil moisture. Within medium gaps, we found a great amount of phenolic compounds and a low content of organic matter and humic acids. These results indicate that in the medium gaps mineralization of organic matter was more important than humification. In contrast, in small gaps, the great amount of organic matter, the high content of humic acid and the values of humification index suggested that in these gaps the humification process of organic matter prevailed. Within small gaps, we observed more silver fir regeneration than medium gaps. Difference in organic matter content, particularly in the amount of phenolic compounds, may account for differences observed in natural regeneration of silver fir between small and medium gaps.

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