Document Type : Research Paper - Plant Physiology
Authors
1 Associate Professor, Department of Horticultural Science and Engineering, Orientation of Medicinal Plants, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
2 Graduated Master of Horticultural Sciences and Engineering, Majoring in Medicinal Plants, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
3 Professor of Horticultural Science and Engineering Department, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
4 Ph.D. Student in Physiology of Production and Post-Harvest of Horticultural Plants, Department of Horticultural Science and Engineering, Faculty of Agriculture, University of Tabriz, Tabriz, Iran.
Abstract
Introduction: Salinity is one of the environmental stresses that has a negative effect on the growth and development process and causes oxidative stress in plants. By creating harmful changes in the balance of ions, water status, nutrients, stomatal function and photosynthesis efficiency, salinity causes a decrease in plant growth and development processes such as germination, seedling growth, and finally, a decrease in the amount of crop production in the plant. Sodium nitroprusside is a relatively stable gas radical that prevents the production of reactive oxygen radicals in low concentrations. It has been reported that sodium nitroprusside as a signal conducting molecule in various physiological processes such as seed germination, leaf senescence, ethylene production, stomatal closure and various defense responses to biotic and abiotic stresses such as salinity, drought and UV-B radiation is involved. Also, sodium nitroprusside plays a role in regulating various developmental processes and plant growth, including root growth, respiration, flowering, and cell death. Considering the positive effects of sodium nitroprusside on plants and the importance of evening primrose, the aim of this research was to investigate the effect of sodium nitroprusside on improving the morphological and physiological properties of evening primrose medicinal plant in adjusting salinity stress in greenhouse cultivation.
Materials and methods: In the present experiment, the effect of salinity stress caused by sodium chloride at four levels (0, 4, 8, 12 dS/m) and its modification by sodium nitroprusside as foliar spraying at four concentrations of zero (control), 0.05, 0.1, 0.15 mM as sodium nitroprusside releasing compound in evening primrose was carried out factorially based on a completely randomized design in three replications in the greenhouse of Horticultural Sciences, Faculty of Agriculture, University of Tabriz. Salt treatment (NaCl) was applied after planting in pots and two times in the form of a solution in water and injected into the plant roots, and nitroprusside treatment was applied at four levels and with an interval of two weeks until flowering (mid-spring). It was done to the leaf. To facilitate sodium nitroprusside foliar spraying and also to increase accuracy, a sprayer was used so that foliar spraying is done uniformly on the aerial part of the plant. At first, the test of normality of the data and the uniformity of intra-treatment variances was performed and confirmed. Analysis of the variance of the data was done factorially in the form of a completely randomized design in three replications. The mean comparison of the treatments was done by Duncan's test at the probability level of 1%. SAS software (Ver. 9.3) was used for data analysis and Excel software was used for drawing graphs.
Results and Discussion: In total, the results of the present experiment showed that the application of salinity treatment caused a significant decrease in fresh and dry weight of leaves, the amount of leaf area and leaf chlorophyll index, while it caused a significant increase in the percentage of ionic electrolyte leakage. The decrease in leaf area due to salt stress is either as a result of a decrease in the number of leaves due to a decrease in photosynthesis or a decrease in leaf size due to a decrease in turgor pressure. So that the highest number (47/08) was obtained in the 4 decisimons treatment and per meter and leaf area (247/95) in the control treatment. Also, the highest percentage of ionic electrolyte leakage (27.5%) was observed at a concentration of 12 deci-siemens/m, but the effect of different concentrations of salinity on the amount of antioxidant activity was not significant. The results showed that sodium nitroprusside treatment caused a significant decrease in leaf dry weight, ion electrolyte leakage percentage. On the other hand, it has caused a significant increase in dry matter percentage, leaf surface, chlorophyll index and antioxidant activity. So that the maximum amount of leaf area, chlorophyll index and antioxidant activity was obtained in the concentration of 0.15 mM sodium nitroprusside.
Conclusion: Sodium nitroprusside has a useful and effective role in improving the growth characteristics and function of aerial organs and the quantitative and qualitative characteristics of evening primrose. So that the concentration of 0.15 mM was considered as the optimal concentration for improving the morphological and physiological traits.
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