Parisa Sheikhzadeh; Gholam Behzad; Nasser Zare; Mitra Rostami
Abstract
To investigate the effects of selenium nanoparticles application on photosynthetic and biochemical characteristics and cold tolerance of oilseed rape, an experiment was carried out based on a randomized complete blocks design with three replications in the research farm station of the University of Mohaghegh ...
Read More
To investigate the effects of selenium nanoparticles application on photosynthetic and biochemical characteristics and cold tolerance of oilseed rape, an experiment was carried out based on a randomized complete blocks design with three replications in the research farm station of the University of Mohaghegh Ardabili in 2018. The treatments consisted of foliar application of selenium nanoparticles (0 as control, 25, and 50 mg L-1) applied at the 8-6 leaves stage. The results showed that selenium nanoparticles application significantly increased the RWC, photosynthetic pigments, antioxidant enzyme activity, winter survival, and grain yields of oilseed rape plants. The highest RWC, Fm, Fv, and Fv/Fm, proline content, and the activity of catalase and peroxidase enzymes were obtained with foliar application of 50 mg L-1 selenium nanoparticles. It seems that selenium nanoparticles application significantly increased the winter survival of oilseed rape plants by about 7.18 to 8.94 percent, by improving the Fv/Fm, the activity of the antioxidant enzymes, and proline content. Foliar application of 25 and 50 mg L-1 selenium nanoparticles caused about 28.10 and 34.19 percent increase in grain yield of oilseed rape as compared to control (no spraying) treatment, respectively. In general, the application of 50 mg L-1 selenium nanoparticles had positive and significant effects on the photosynthetic and biochemical characteristics, which resulted in increased cold tolerance of the oilseed rape plant.
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 ...
Read More
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.
Somaye Amraee Tabar; Ahmad Ershadi
Abstract
In this study, the drought tolerance threshold and relationships between some biochemical and physiological responses of two stone fruit rootstocks, Cadaman and GF677, have been investigated. For this purpose, a pot experiment has been carried out in a greenhouse using factorial trial based on a completely ...
Read More
In this study, the drought tolerance threshold and relationships between some biochemical and physiological responses of two stone fruit rootstocks, Cadaman and GF677, have been investigated. For this purpose, a pot experiment has been carried out in a greenhouse using factorial trial based on a completely randomized design with three replications. One-year-old rooted cuttings of two rootstocks are exposed to drought stress (-0.1 (control), -0.6, -1.1, -1.6 MPa) by adding different amounts of polyethylene glycol-6000 to Hoagland nutrient solution. Significant increase in electrolyte leakage and decrease in leaf relative water content of Cadaman and GF677 rootstocks has occurred at -0.6 and -1.1 MPa, respectively. Concentration of photosynthetic pigments and quantum yield of photosystem II (FV/FM) are less affected by drought stress, decreasing significantly in Cadaman and GF677 rootstocks at -1.1 and -1.6 MPa, respectively. Under severe drought stress, photosynthesis, transpiration, intercellular CO2 concentration, and stomatal conductance in Cadaman rootstock decline more considerably, compared to GF677. Moreover, at drought stress of -1.6 MPa, GF677 does not significantly reduce its photosynthesis, despite a substantial decrease in transpiration; however, the relative decrease in photosynthesis of Cadaman at -1.6 MPa has been much greater than the relative decrease in its transpiration and intercellular CO2 concentration, which, in turn, results in a drop in water use efficiency and mesophilic conductance of Cadaman leaves, compared to GF677. It seems that considerable reduction in photosynthesis in Cadaman rootstock, along with stomatal limitations, is largely due to non-stomatal constraints such as loss of cell membrane intact and reduction of chlorophyll, carotenoids and chlorophyll fluorescence. Results show that GF677 rootstock has higher tolerance to severe drought stress, compared to cadaman.