The effect of different levels of salinity stress and cultivar on biochemical and physiological characteristics and nutrient concentration of William Sweet (Dianthus barbatus)

Salinity is one of the main environmental stresses that affects seedling establishment and plant yield. Salinity stress often limits plant growth and productivity, and this stress is affected by a variety of processes. Dianthus barbatus belongs to the Caryophyllaceae family and is one of the most important ornamental plants in the open air, which gives a special beauty to the environment in spring. This plant grows in a wide range of climatic conditions. Due to the fact that extensive research on salinity stress threshold and cultivar resistance in this plant has not been studied, so this study aims to investigate the effect of different levels of salinity stress and cultivar type on some physiological, biochemical and nutrient concentration of Dianthus was done in greenhouse conditions.

This experiment was performed in November 2019 in the research greenhouse of Khomeyn Municipality located in Markazi province, as a factorial, in a completely randomized design, with three replications. The first factor was cultivars at two levels (including Diana and Barbarin cultivars), the second factor was salinity due to sodium chloride at 10 levels (including 0, 10, 20, 30, 40, 50, 60, 70, 80 and 90 mM). The seeds were prepared from a Dutch company and planted in pots containing soil, manure and sand. The traits measured in this experiment included the concentration of NPK, calcium, magnesium, sodium, photosynthetic pigments, carotenoid content, proline, Electrolyte Leakage, Lipid peroxidation, relative leaf water content (RWC) and leaf enzyme activity (catalase and peroxidase)

The results of ANOVA showed that the main effects and interactions of salinity stress and cultivar were significant for catalase, peroxidase, potassium uptake and Electrolyte Leakage. As the concentration of sodium chloride increased, the amount of chlorophyll and carotenoids, the concentration of calcium, magnesium, nitrogen, phosphorus and RWC decreased, and the amount of malondialdehyde, electrolyte Leakage, enzyme activity, proline and absorption of sodium and potassium increased. Among the two cultivars studied, Barbarin cultivar was more tolerant to salinity stress than Diana cultivar. The highest uptake of potassium (5.157%) in Barbarin cultivar under non-stress conditions, the lowest (14.79%) in Diana cultivar under severe stress conditions (90 mM). The highest sodium uptake (1.36%) was reported in severe stress conditions (90 mM) and the lowest uptake (0.2196%) in non-stress conditions. Sodium uptake in Barbarin cultivar (0.5082%) was lower than Diana cultivar (0.5474%) which indicated that this cultivar was more resistant to sodium uptake.

According to the results of the present study, with increasing sodium chloride concentration, physiological parameters such as chlorophyll and carotenoid content and relative leaf water content decrease and biochemical parameters such as malondialdehyde content, enzyme activity, sodium and potassium uptake, electrolyte leakage and Proline increased. The results of this study showed that the cultivars studied in this study were resistant to low salinity (10-40 mM) and somewhat sensitive to moderate and severe salinity (50-90 mM). Among the studied cultivars, Barbarin cultivar was more tolerant to moderate and severe soil salinity than Diana cultivar. Also, according to the results, the optimal limit under salinity stress for carnation was about 50-60 mM salinityKeywords: Nutrient uptake, salinity stress, chlorophyll, carnation, RWC