Effect of Nano Titanium Dioxide and Sodium nitroprusside on seed germination, vigor index and antioxidant enzymes of Afzal barley seedling under salinity stress

Salinity is the most important factor limiting growth and yield of crops in many area of the world. In order to study the effects of nano-TiO2 (0, 500, 1000, 2000 mg/L) and sodium nitroprusside (0 and 100 μM) on seed germination and antioxidant content of barley (var. Afzal) under salinity stress (0, 50 and 100 mM Sodium chloride) a factorial experiment based on a completely randomized design with four replications was conducted. Salinity stress declined the germination indices such as, germination percentage, germination rate, radicle length, plumule length, vigor index, mean germination time, relative water content and increased the membrane electrolyte leakage. In the presence of nano-TiO2, most of germination indices improved and the content of CAT, APX and especially SOD enzymes increased. Use of Sodium nitroprusside diminished the adverse effects of salinity stress and decreased the membrane electrolyte leakage. Also the interaction effect of sodium nitroprusside and nano-TiO2 was significant on the most studied traits. Nano-TiO2 (500 mg/L) with SNP improved SOD, APX and CAT enzyme contents by about 28, 16.8 and 17.9 % under 100 Mm salinity stress. According to the results, it seems that sodium nitroprusside diminished the adverse effects of salinity stress and impressed the nano-TiO2 performance on barley germination indices and antioxidant enzymes content.