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The hydrophyte Azolla filiculoides can be a useful model to assess if TiO2 NPs may in some way alleviate the Cd injuries and improve the ability of the plant to cope with this metal. With this mechanistic hypothesis, after a pre-treatment with TiO2 NPs, A. filiculoides plants were transferred to cadmium-contaminated water with or without TiO2 nanoparticles. After 5 days of treatment, cadmium uptake, morpho-anatomical, and physiological aspects were studied in plants. The continuous presence of TiO2 nanoparticles, though not increasing the uptake of cadmium in comparison with a priming treatment, induced a higher translocation of this heavy metal to the aerial portion. Despite the translocation factor was always well below 1, cadmium contents in the fronds, generally greater than 100 ppm, ranked A. filiculoides as a good cadmium accumulator. Higher cadmium contents in leaves did not induce damages to the photosynthetic machinery, probably thanks to a compartmentalization strategy aimed at confining most of this pollutant to less metabolically active peripheral cells. The permanence of NPs in growth medium ensured a better efficiency of the antioxidant apparatus (proline and glutathione peroxidase and catalase activities) and induced a decrease in H2O2 content, but did not suppress TBARS level. [ABSTRACT FROM AUTHOR]

Interchangeable effects of temperature, moisture content and oxygen on seed longevity have been mostly examined to estimate seed viability during long-term dry storage, whereas few experiments have studied seed viability under near-natural conditions to evaluate seed persistence in the soil. To this end, we artificially aged seeds of Ranunculus baudotii, a hydrophyte widely distributed in temporary ponds constituting an abundant soil seed bank. Seeds were exposed to controlled ageing at three different relative humidities (RH) under both aerobic and anoxic conditions. Their viability, water content, membrane damage, oxidative stress and anti-oxidant enzymatic defence activity were evaluated. Seed survival was longer at higher relative humidity (97% RH), and lowest at a relative humidity (90% RH) simulating moist but not waterlogged soils. Anoxic conditions showed a protective role on viability at lower moisture contents (70% RH). Seed viability was negatively associated with hydrogen peroxide content and correlated with anti-oxidant enzyme activities, but not with membrane damage. Altogether, these results suggest negative roles for moist soils and anoxia in determining seed persistence in the field, but at higher moisture contents the negative effects of anaerobia diminished. The anti-oxidant system activation, even under unfavourable conditions, might recover seeds once all protective processes can operate, pointing out the plasticity of mechanisms involved in seed loss viability. [ABSTRACT FROM AUTHOR]

Flours of four pigmented (from orange to red and dark red) local Italian corns, studied for their soluble, soluble conjugate, and insoluble-bound phenols and flavonoids, showed a prevalence of the insoluble-bound fraction (70–80%). Correlations were found between the flours antioxidant capacity, measured with CUPRAC, FRAP, and DPPH methods, and soluble phenols and flavonoids content. A correlation was also found between ascorbic acid content and flours antioxidant power. Anthocyanins were present in small amounts in the red/dark red seeds; however, acid-alcohol assays and spectral analyses of pericarp extracts indicated the presence of red-brick phlobaphenes in these varieties. Spectrophotometrically quantified total carotenoids were significantly higher in one of the local varieties (Nano); RP-HPLC analyses indicated that the local varieties contained significantly higher amounts of zeaxanthin and β-carotene, and lower amounts of lutein, than a commercial line. Among local varieties, Nano expressed the highest levels of zeaxanthin, β-carotene, and β-cryptoxanthin. [ABSTRACT FROM PUBLISHER]