Effect of potassium silicate on growth, physiological and biochemical characteristics of Pelargonium graveolens under salinity stress

This research was carried out to evaluate the effect of potassium silicate on geranium reaction to salinity stress in 2014. The experiment was done hydroponically in pots filled with sand. Experiment was laid out factorially based on a completely randomized design with four replications each replication included 9 treatment compositions with 36 pots. Factors consisted of daily application of 1.8, 4 and 6 ds/m NaCl and weekly application of 0, 0.5 and 1 mM potassium silicate through nutrient solution. Result showed that by increasing salinity, growth parameters, essential oil, relative water content and the activity of catalase and peroxidase decreased while Malondialdehyde, electrolyte Leakage and amount of proline increased. Application of potassium silicate improved growth and physiological and biochemical characteristics ofgeranium under salinity stress. Moreover, leaf Na increased while P content decreased, respectively, as salinity increased and application of potassium silicate increased P and decreased Na under salinity in canopy of plant. Many characters i.e. leaf area, shoot fresh and dry weights values returned to control as 1mM potassium silicate was applied. Overall, the results showed that increasing salinity pronounced stress symptoms and weekly application of potassium silicate especially at 1 mM, alleviated the stress effects.