The Effect of Different Levels of Silicon from a Source of Silicic Acid on Aloe vera L. Growth Traits under Cold Stress

Due to the importance of useful elements such as silicon in improving plant resistance to environmental and biological stresses, a factorial experiment was conducted in a completely randomized design in Hashtgerd city, hydroponic greenhouse No. 256. Experimental factors included temperature at 4°C (stress temperature) and 25°C (optimum growth temperature) and application of silicon fertilizer from source of silicic acid at five levels; 0, 500, 1000, 1500 and 2000 mg/kg with three replications, in total 30 pots. The measured traits included the activity of superoxide dismutase (SOD), catalase (CAT), antioxidant enzymes and the qualitative characteristics of aloe vera consist of Mannose, Glucomannan and Aloin concentrations and the plant growth characteristics including aloe vera gel and leaf weight, which were tested at 4°C as cold stress temperature and 25°C as the optimum growth temperature of the plant. The obtained results after applying cold stress showed that the effect of silicon fertilizer levels applied on (SOD) and (CAT) and Glucomannan and Mannose activities were significant at 1% level. It was also observed that the interaction of different concentrations of silicon fertilizer and temperature stress is significant at 1% level on all compounds. For vegetative and biochemical traits, the highest interaction was observed in treatment of 2000 mg/kg silicic asid fertilizer at 25°C. For antioxidants, the highest interaction was found in treatment of 2000 mg/kg silicic acid and stress temperature of 4°C. Therefore, the application of 2000 mg/kg pure silicon could have positive effects on the activity of antioxidant enzymes and vegetative traits at normal temperature and a more favorable effect on biochemical traits under temperature stress. Consequently, the silicium fertilizer can be applied as a useful and suitable element in ncreasing the quantity and quality of aloe vera plant.