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Showing 2 results for Selenium
The effect of metallic selenium and nano on the physiological characteristics of tomato plants
M. Haghighi, R. Abolghasemi,
Volume 9, Issue 1 (5-2018)
Abstract
Selenium (Se) is an important microelement for plants and has been shown to improve growth under normal and stressed conditions. In this study, effect of Se and nano-selenium (N-Se) on hydroponically-grown tomato (Lycopersicum esculentum Mill. cv. ‘Halil’) on photosynthesis, antioxidant activity and total polyphenolic content was assessed. A factorial experiment with three temperature levels and Se and Nano Se level was designed. All plants were first exposed to Se or N-Se [Se at 0 µM (control), 2.5 µM (Se1), 5 µM (Se2) and 8 µM (Se3)], while N-Se was applied at four levels [1 µM (N-Se1), 4 µM (N-Se2), 8 µM (N-Se3) and 12 µM (N-Se4)]. Plants were exposed to three temperature levels [optimal temperature (25.17 ± 2 °C day/night = T1), high temperature (40 °C for 24 hr = T2) and low (chilling) temperature (10 °C for 24 hr = T3)]. They were then placed at normal temperature conditions for 7 days and photosynthetic and antioxidant factors were measured. Based on the results, both temperature-related stresses had negative effect on tomato growth. However, under high temperature stress, photosynthetic rate, mesophyll conductance and photosynthetic water use efficiency improved significantly. While, cold stress significantly enhanced transpiration. Most photosynthetic parameters could be improved in the presence of Se and N-Se. In Se1 treatment, under the temperature stress, the best photosynthetis rate, respiration and mesophyll conductance were obtained and plant resistance was enhanced. In N-Se treatments, N-Se1 had the best results of photosynthetis rate, antioxidant and phenol. However, in the absence of stress, the use of Se or N-Se, especially at higher concentrations (i.e., 5 and 8 µM), negatively impacted photosynthetic rate, internal CO2 of stomata, mesophyll conductance and photosynthetic water use efficiency. In general, under the low and high temperature stress, the physiological parameters of tomato were improved in N-Se1 treatment.

Effect of Different Levels of Sodium Selenate and Selenite on Morphological Characteristics and Nutrients Concentration in Peppermint
H. Jafari, M. Moghaddam,
Volume 13, Issue 3 (12-2022)
Abstract 
To investigate the effect of sodium selenate (Na2SeO4) and sodium selenite (Na2SeO3) on some morphological characteristics and nutrients concentration in peppermint, an experiment was conducted in a completely randomized design with four replications. Different levels of sodium selenate and sodium selenite (0, 4, 8, and 12 mg l-1) were applied in soilless cultivation in the research greenhouse of the Faculty of Agriculture, Ferdowsi University of Mashhad. Then morphological traits and the concentrations of nutrients in the leaf were measured in the flowering stage. The results showed that the application of two forms of selenium at a concentration of 4 mg l-1 increased the growth traits in peppermint. The highest concentration of both salts decreased the plant growth. The results also showed that with increasing the concentration of selenite and sodium selenate, the selenium concentration increased, but the use of sodium selenate caused higher concentration of this element in the leaf. At a concentration of 4 mg l-1 selenium, the concentrations of macronutrients including nitrogen, phosphorus, potassium, calcium, and magnesium in the leaf increased by 43.7, 11.1, 3.2, 11.6, and 9.2%, respectively, compared to the control but were not significant. The highest nitrogen concentration was observed at the concentration of 4 mg l-1 sodium selenite 43.7% greater than the control. With increasing the concentration of selenium, except for molybdenum and manganese, the concentration of zinc, iron, boron, and copper increased. The highest concentrations of iron and boron were obtained at 12 mg l-1 sodium selenate, 60.2 and 25.7% greater compared to the control, respectively. The highest concentrations of zinc and copper measured at 12 mg l-1 sodium selenite were 63.3 and 40.6% greater than the control, respectively. In general, it is concluded that 4 mg l-1 of sodium selenate can be applied to improve the growth and nutritional condition of the peppermint.

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