The Effect of Nano Selenium and Sodium Selenate on Growth and Photosynthesis Parameters of Spinach (Spinacia oleracea L.) Virofly Variety

Introduction:Selenium is an essential element for humans and animals.Seleno-proteins contribute in antioxidant regulation, so the deficit leads to dysfunction of immune system.Plants, the main source of this element for mammals, absorb selenium from the soil.Nanotechnology, as a promising area of biology, has introduced stable particles as fertilizers.Foliar application of nano-selenium in plants has been involved in alternation of photosynthetic pathway and generation of secondary metabolites.Since selenium is one of the useful elements in plants (including spinach) and due to toxic effects of this element under high concentrations, in this study, the effects of bulk or nano forms of selenium were compared on spinach plants.The research aimed to compare foliar spraying of sodium selenate (5, 10 and 20 mg/L) with nano-selenium (5, 10 and 20 mg/L) on growth parameters, photosynthetic indices and selenium content in spinach. Materials and Methods:The current study was carried out under greenhouse conditions in horticulture department, Hormozgan university, 2022.The experiment was designed as a completely randomized design.The spinach virofly variety was used.The treatments were included foliar spraying of drip irrigation with distilled water (control plants), sodium selenate (5, 10 and 20 mg/L) nano selenium (5, 10 and 20 mg/L).Growth parameters (including leaf number, leaf and root dry matter, plant and root length), photosynthetic indices (including intercellular CO2, stomatal conductance, photosynthetic rate, transpiration rate, chlorophyll (a,b, total) and carotenoid contents) and selenium content were evaluated.The normality of the data was checked by the Shapiro-Wilk test.Tukey's test was used for mean comparisons (P < 0.01, 0.05).The data statistical analysis was perfumed by SAS Ver.9.4.Also, the figures were drawn using EXCEL 2016.Results and Discussion: Based on the results of analysis of variance, the effect of treatment (nano selenium and sodium selenate) was significant on leaf dry matter, root dry matter, shoot length, root length and leaf number (P 0.05).The effect of treatments was significant on carotenoids (P 0.01), chlorophyll a, chlorophyll b, total chlorophyll (P 0.05), leaf stomatal conductance, photosynthesis (P 0.01), intracellular CO2 concentration and transpiration (P 0.05).Based on findings, root dry matter, shoot length, leaf number, total and chlorophyll a content, carotenoid, photosynthesis rate, intercellular carbon dioxide, stomatal conductance and leaf Se content improved 25.69, 54.78, 14.99, 23.11 and 8.86, 31.01,222.39, 40.49, 132.25 and 26.31 %, respectively via enhancing the levels of both treatments, compared to the control.Despite recording the highest amount of leaf dry matter (25.69%), leaf number (30.67), intercellular CO2 (476.46