THE EFFECT OF TITANIUM DIOXIDE NANOPARTICLES AND SALICYLIC ACID ON GROWTH AND BIODIESEL PRODUCTION POTENTIAL OF SUNFLOWER (HELIANTHUS ANNUUS L.) UNDER WATER STRESS

Biodiesel is a green fuel derived from vegetable oil and animal fats. In present studies we evaluated effects of salicylic acid (SA) and Titanium dioxide nanoparticles (nano-TiO2) on growth and biodiesel production potential of sunflower (Helianthus annuus L.) varieties S-78 and Armoni under water deficit stress. The water deficit stress (50% and 30% field capacity of soil) was imposed during reproductive growth for one month. Salicylic acid (5 and 3 mg/L) and nano-TiO2 (50 and 25 mg/L) was applied to leaves as a spray once before the start of water deficit stress period and next foliar spray 15 days after imposition of water stress. We observed that severe water stress (30% field capacity) significantly decreased plant leaf area, leaf relative water content (LRWC), chlorophyll a, b and carotenoids content, head diameter, width and length of achene, 1000 achene weight, achene oil content and biodiesel yield. Severe water stress (30% field capacity) increased oil acid value and free fatty acids content but decreased oil iodine value and refractive index. The foliar spray of salicylic acid and nano-TiO2 effectively alleviated adverse effect of water deficiency stress on growth, achene quality and biodiesel yield of sunflower varieties. The sunflower variety Armoni performed better and showed better response to applied SA and Nano-TiO2. Moreover, influence of nano-TiO2 and SA on sunflower under water stress was nearly comparable. We concluded that foliar spray of either nano-TiO2 (50 mg/L) or SA (5 mg/L) could be highly effective in the alleviation of adverse effect of water deficit stress on the biodiesel production potential of sunflower.