Alpha-Tocopherol Induced Modulations in Morpho-Physiological Attributes of Sunflower (Helianthus annuus) Grown under Saline Environment

Among abiotic stresses salinity is one of the serious threats for food security worldwide. Sunflower is ranked 5th among crops grown for food security and being moderately salt tolerant is a better choice for growing on saline soil. Application of various compounds including vitamin E might be a beneficial technique for improving growth in plants under saline conditions. A pot experiment was conducted to explore the role of alpha tocopherol seed treatment for inducing salt tolerance in sunflower. Seeds of two sunflower cultivars (FH-572 and FH-621) were soaked for 16 h in four levels of alpha tocopherol i.e. control (distilled water), 100, 200, 300 mg L-1 and two levels of NaCl salt (0 and 120 mM) were applied with full strength Hoagland's solution 35 days after seed sowing. Salt stress caused significant decrease in shoot and root fresh weight, leaf relative water content and inhibition in shoot length. Salinity stress increased leaf turgor potential and had non-significant effect on photosynthetic pigments, osmotic potential and gas exchange characteristics. Seed treatment with a-tocopherol considerably increased shoot and root fresh weight, shoot length, net CO2 assimilation rate, stomatal conductance (g(s)) and water use efficiency; however, it showed non-significant effect on photosynthetic pigments, leaf water relation parameters and transpiration rate. Alpha tocopherol, 100 and 300 mg L-1 levels were effective in ameliorating the negative impact of salt stress in cv. FH-572 and cv. FH-621, respectively. Results depicts great varietal difference in salinity tolerance and cultivar FH-621 performed better than cv. FH-572 under salinity stress. (C) 2018 Friends Science Publishers