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Salinity tension is a growing problem in agricultural soils. In order to investigate the interaction of Na+-Ca2+ on biomass and antioxidant enzymes activity of peroxidase and polyphenol oxidase in leaf of barley, this research was conducted as a completely randomized design with three replications in greenhouse conditions (temprature 25°C, 35 percentage relative humidity and 16 hours lighting photoperiod). The seedlings were treated by levels zero, 50, 100 and 150 mM of NaCl and with levels zero, 6 and 10 mM of CaCl2 one week after planting seeds in soil. After five weeks applying the treatment, some morphological and physiological parameters including dry weight of shoot and root and peroxidase and polyphenol oxidase enzymes activity in leaf were assessed. Results showed that salinity tension significantly decreased the dry weight of shoot and root, however, increased the peroxidase and polyphenol oxidase enzymes activity in leaf. While, adding calcium to salty environment significantly increased dry weight of shoot and root yet decreased peroxidase and polyphenol oxidase enzymes activity in leaf. Calcium decreased the harmful effect of salinity tension and the maximum ameliorative effect of calcium was observed in 6 mM CaCl2 concentration.

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Seed priming technique (pretreatment)is one of the effective methods in rapid establishment and improvement of reproductive characteristic of rice under direct cultivation conditions. In order to investigate the effect of osmotic and water priming (osmopriming and hydropriming) on yield and yield components improvement of two rice cultivars, a factorial experiment was conducted in the research farm of Sari University of Agricultural Sciences and Natural Resources in a randomized complete blocks design with three replications in spring 2019. Experimental factors included two Tarom and Shiroudi cultivars and priming at five levels including hydropriming (24 hours), calcium chloride (osmotic potential of 1/25-Mega Pascal in 24 hours), potassium chloride (osmotic potential of 1/25-Mega Pascal in 24 hours), ascorbate acid (10 milligram per one liter water in 24 hours) and control (no priming). The results of the cultivar effect showed that the percentage of emergence with 88 and 78 and the rate of emergence with 0.2 and 0.15 per day were obtained in Shiroodi and Tarom cultivars, respectively. Also, the effect of priming on emergence rate was significant at one percent probability; so that the highest germination rate was obtained in priming with calcium chloride, potassium chloride and water, which increased by 50, 36 and 29 percent, respectively, compared to the control treatment. The highest rice plant height was obtained in Shiroudi cultivar under priming with calcium chloride, potassium chloride and water with 107, 104 and 103 centimeters, respectively. The results showed that the amount of chlorophyll index of different vegetation layers in all treatments of priming in Shiroodi cultivar was higher than Tarom cultivar. The highest grain and higher biological yields were obtained with 5513 and 13223 kilogram per hectare in Shiroodi cultivar, respectively. Priming with calcium chloride, potassium chloride, ascorbate and water increased grain yield by 19, 14, 10 and 14 percent, respectively, compared to the control treatment.  
 

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In order to investigate the effect of silica and calcium content and harvest dates on yield and yield components of rapeseed as a factorial split in a randomized complete block design with three replications in experimental farms in Aftab region of Tehran province in two cropping years 2018-2019 and 2019-2020 were implemented. Experimental factors include harvest date in three levels one week after the start of yellowing of pods, two weeks after the beginning of yellowing of pods and time of complete yellowing of pods, silica in three levels of zero (control), 3 and 6% of the source was sodium and calcium silicate at three levels of 2, 4 and 6% of the source of calcium sulfate. The results showed that the effect of year on plant height, number of pods per plant, number of seeds per pod and anthocyanin was significant and the second year had the highest amount of these traits. It was observed that the best grain yield of 2477.02 kg / ha and harvest index of 24.83% was related to harvest one week after the start of yellowing of pods and with delay in harvest, 1000-seed weight, grain yield, Biological yield and harvest index decreased and anthocyanins increased. According to the results, silica foliar application with 32.81% increase in plant height, 11.8% number of pods per plant, 31.48% number of seeds per pod, 17.2% weight per thousand seeds, 24.31% grain yield, Biological yield and harvest index and reduction of anthocyanin and electrolyte leakage were associated. The most positive effect on physiological characteristics and yield and yield components was obtained in 6% silica spray. With increasing calcium concentration, plant height, number of pods per plant, number of seeds per pod, 1000-seed weight, grain yield, biological yield and harvest index decreased and anthocyanin and electrolyte leakage decreased, the maximum positive effect on these traits in foliar application 6% calcium was observed. The results showed that silica and calcium had an additive effect on yield and yield components and the best grain yield was obtained by consuming 6% silica with 6% calcium and harvesting one week after the start of yellowing of pods.