Lacramioara Oprica

Characterizing the effects of salt stress in Calendula officinalis L.

In this study the effects of salt stress on growth and several stress markers were investigated in the ornamental and medicinal plant Calendula officinalis. One month old plants were submitted to increasing concentrations of salt up to 150mM NaCl for a period of 30 days. Salinity affected growth in terms of stem length and fresh weight of the plants, but water content remained unchanged indicating a certain tolerance to low and mild concentrations of salt. Although Na+ and Cl− increased in parallel to applied salt treatments, the levels of K+ and Ca2+ showed no significant change, while Mg2+ levels recorded a two folds increase upon the application of the highest salt concentration. Other measured parameters showed a more significant change, notably proline that registered a nine folds increase under salt stress. In conclusion, although plants suffered from salt stress as shown by the degradation of photosynthetic pigments and increased MDA levels, they continued their vegetative growth under low concentrations of salt. The main mechanisms of response to stress in this species are based on the insurance of K+ and Ca2+ homeostasis and the accumulation of proline as a functional osmolyte.

The effect of visible light on gold nanoparticles and some bioeffects on environmental fungi.

The oxidative stress induced by light exposed gold nanoparticles in some microorganism cells was investigated. Gold nanoparticles are currently used in biomedical and pharmaceutical research. For this study citrate-gold nanoparticles were synthesized in alkaline conditions at constant temperature of 85°C under magnetic stirring. Equal volumes of such prepared colloidal solution, were exposed to visible light at different wavelengths for 90min at room temperature. The spectra in the visible and ultraviolet range have revealed an increase in the intensity of the absorption band for gold nanoparticles exposed to light, due to the effect of surface plasmon resonance. Versatility of gold nanoparticles photocatalytic action was shown by means of manipulating wavelengths of incident light, which evidenced differences in the bioeffects induced in cellulolytic fungi - known for their environmental role but also for other applications such as in cosmetics industry. The comparative analysis of fungal response to gold nanoparticle stressors has revealed different enzyme activity and lipid peroxidation when fungi were supplied with gold nanoparticles exposed to different wavelength lights. The activity of catalase and superoxide dismutase were remarkably increased for green light exposure of gold nanoparticles suggesting fungi adaption to increased oxidative stress induced by irradiated particles; increased level of lipid peroxidation was showed by high concentration of malondialdehyde for white light exposed gold particles since antioxidant enzymes were less active.

Antioxidant properties evidenced by polyphenols content in two Romanian red grape cultivars in Iasi area

Environment protection and management includes preservation of agroindustrial plant species with certificated biological features as source of healthy and safe foods and drinks. Antioxidant properties of fruits were evidenced by total polyphenols content of different parts of grapes (skins, pulps and seeds) in two grape cultivars (Cabernet Sauvignon and Merlot) from two experimental fields (Copou and Bucium vineyards). The total phenolic contents of seeds ranged from 116.56 to 127.90 mg GAE/g lyophilized matter in Merlot cultivars and from 101.64 to 109.29 mg GAE/g lyophilized matter in Cabernet cultivars. Our research reveal that there are variations in total polyphenols content within investigated grape cultivars, both in terms of analyzed fruit components as well as by the location of the two collecting points.