Sara Baniebrahimi; Leila Pishkar; Alireza Iranbakhsh; Daryush Talei; Giti Barzin
Abstract
In order to investigate the physiological responses of black cumin seed (Nigella sativa L.) under different concentrations of silver nanoparticles (0, 2.5, 5, 10, 20, 40, and 80 mg/L AgNPs), a completely randomized design experiment is conducted with 5 replications in the greenhouse of Shahed University ...
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In order to investigate the physiological responses of black cumin seed (Nigella sativa L.) under different concentrations of silver nanoparticles (0, 2.5, 5, 10, 20, 40, and 80 mg/L AgNPs), a completely randomized design experiment is conducted with 5 replications in the greenhouse of Shahed University in 2018. In the present study, growth traits, photosynthetic pigments, anthocyanins, proline content, glycine betaine, soluble and insoluble sugars, phenolic compounds and gas exchange, and fluorescence parameters of the photosynthetic apparatus are investigated. The results show that the AgNPs treatments significantly inhibit biomass production and the growth of root and shoot, decreasing the contents of chlorophyll a and b at high concentrations (20, 40 and 80 mg/L), while the AgNPs treatments increase the content of carotenoids, proline, glycine betaine, soluble sugars, anthocyanins, and phenolic compounds, compared to the control. By increasing the concentration of AgNPs, photosynthetic rate, transpiration rate, stomatal conductance, the maximal quantum yield of PSII photochemistry, photochemical quenching coefficient, and effective quantum yield of PSII photochemistry decline. Measurement of fluorescence show strong evidence of inhibitory effects on energy transfer from light harvesting complexes to reaction centers, the deterioration of the PSII water splitting system and the inactivation of PSII reaction centers at high concentrations of AgNPs. In conclusion, the results demonstrate that AgNPs induce an inhibitory mechanism on photosynthetic processes and biomass of black seed plants.
Dariush Talei; Reza Sharifi; Mahdi Pirsalehi
Abstract
In order to investigate the morpho-physiological responses of Purslane plant to methyl jasmonate under salinity stress a split plot based on a completely randomized design with two factors and three replications was carried out in medicinal plants research center, Shahed University, Tehran during 2017. ...
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In order to investigate the morpho-physiological responses of Purslane plant to methyl jasmonate under salinity stress a split plot based on a completely randomized design with two factors and three replications was carried out in medicinal plants research center, Shahed University, Tehran during 2017. The factors were, salinity with four levels (0, 3, 6 and 9 dS/m) as a main factor and methyl jasmonate with four levels (0, 0.25, 0.5 and 0.75 mM) as a sub factor. The results showed that by increasing salinity levels, the growth indices such as root length, fresh weight of root, chlorophyll b, total chlorophyll and the amount of superoxide dismutase decreased, while by increasing the salinity levels the proline content and the activity of catalase and MDA in the leaf increased. Applying methyl jasmonate under salinity stress reduced the growth indices and photosynthetic pigments. The highest number of branches, number of leaves and chlorophyll b was obtained at 6 dS/m salinity and 0.5 mM methyl jasmonate. By increasing methyl jasmonate level, the proline content and the activity of CAT increased, while the amount of MDA and SOD enzymes decreased. Therefore, it can be concluded that the is the tolerance of Portulaca oleracea plant to salinity was up to six dS/m, and consuming low amounts of methyl jasmonate can improve yield and physiological indices in Purslane.