Effect of Ca and Nano-Ca Spray on Reducing the Effects of Salinity Stress on Tomato at Vegetative Growth Stage in Hydro culture

Salinity has deleterious effect through ion toxicity and changes nutrient balance on plant growth parameter. For decreasing the hazardous effect of salinity stress, some effort has done to reduce uptake and accumulation of Na. Adding of Ca decreased these deleterious effect of salinity. Calcium ions have significant effects on the physiological processes of plants and improve the morphological and biochemical factors of plants under salinity stress. The effect of calcium on reducing the harmful impacts of salinity from sodium depends on the plant type, calcium concentration and sodium source. Recently, the addition of nanoparticles to plants as fertilizers has attracted the attention of researchers because of its unpredictable effects, such as faster and easier penetration into the membrane of the cell. A few studies have examined the effect of different nanoparticles on the growth and physiology of plants. So, a research was conducted to investigate the effects of salinity and supplemental calcium in the form of spraying into two metal and nano-metal forms on vegetative growth of tomato plants under crop cultivation conditions. To study the effect of CaCl2 and Nano-Ca on tomato (Lycopersicon escuhentum var. Falcato), a factorial experiment based on completely randomized design (CRD) with 4 replicates was designed with NaCl (0, 25 and 50 mM) and Ca and N-Ca (0, 150 and 200 mg/l) in Isfahan University of Technology greenhouse. Indicators include chlorophyll index, relative water content, ion leakage, leaf water potential, root and shoot dry weights, root and shoot length and root volume were measured. Finally, the analysis of the results was done by statistical statistic software and comparing the meanings by LSD test at 5% level. Results showed that Ca and Nano-Ca was effective on decreasing hazardous effect of salinity on fresh and dry weight of shoot and root volume and Ca was more effective than Nano-Ca. In high salinity level (50mM NaCl), application of 150 mg/l Ca increased fresh and dry weight of root, fresh weigh of shoot and root volume by 60, 63, 50 and 70 % compare to control ,respectively. As well as, the highest root length and shoot was observed in this treatment. Application of 200 mg/l calcium and 150 mg/l of nano-calcium significantly improved chlorophyll content in 50 mM sodium chloride treatment. The plant's compatibility mechanism is very complex in the salinity conditions, from reasons for the growth of the plant under saline conditions are the accumulation of toxic ions, chlorine and sodium in plant tissues, which reduces enzyme activity and changes the pattern of carbohydrate distribution. Loss of the fresh and dry weight shoots and root of tomato has been reported in salinity conditions, which can be attributed to reduce plant growth due to the decrease in leaf area growth and thus the reduction of photosynthesis and the production of proteins. There is little research on the use of nanoparticles in plant growth and the use of nano-calcium has been used to reduce salinity stress for the first time, but the beneficial effects of some nano-materials on plants have been proven. With the use of titanium and nano-titanium in spinach, nano-titanium increases the fresh and dry weight of the plant relative to the use of titanium. In this study, the effects of calcium salinity stress were observed, but nano-calcium had less effects than calcium, and probably due to the fact that the concentrations of nano-calcium were used, using less concentrations in future research to achieve possible concentrations are suggested. The use of nano-calcium to reduce salt stress was used for the first time in this experiment. The results of this experiment showed that the application of 150 mg calcium per liter on many tomato traits such as root and shoot fresh weight, root length shoots and root volume were effective under salinity stress, especially intense salinity (50 mM sodium chloride). The comparison of the effects of calcium and nano-calcium showed that the particle size reduction hadn’t shown a significant effect on calcium salt modification and may be due to the concentrations of nano-calcium. Therefore, nanotechnology needs more research in the application of nano-calcium and other nano-materials. Ca also alleviated the hazardous effects of salinity but comparing Ca and nano-Ca showed that nano-Ca has not significant alleviating effect on salinity stress.