Nano-titanium Dioxide (Nano-TiO2) Mitigates NaCl Stress by Enhancing Antioxidative Enzymes and Accumulation of Compatible Solutes in Tomato (Lycopersicon esculentum Mill.)

In recent years nano materials have been emerged as potential source of plant growth and development. Of these, nano-TiO 2 plays important role in several plant developmental processes including defence against environmental stresses. Present investigation was carried five to test, whether nano-TiO 2 could improve growth, yield and quality of tomato fruits under salt stress. Tomato plants were grown with 200 mM NaCl and/or five levels of nano-TiO 2 viz., 0, 5, 10, 20 and 40 mg LG 1 . The results show that 200 mM NaCl inhibited all the growth attributes and physiological and biochemical parameters except plant height. However, salt stress enhanced the activities of antioxidant enzymes (SOD and POX), H 2 O 2 content and TBARS and compatible solutes [proline (Pro) and Glycine Betaine (GB)] content. Salt stress also suppressed all the yield attributes except fruit number. Regarding quality attributes, salt stress reduced lycopene content, whereas, total phenolics and antioxidant capacity was increased under salinity. However, foliar spray of nano-TiO 2 overcame deleterious effects of salt stress and improved most of these parameters. Out of five levels, of 20 mg LG 1 nano-TiO 2 proved best which improved the activities of carbonic anhydrase, nitrate reductase, SOD and POX and accumulation of Pro and GB. Cumulative effect of these parameters contributed to improved growth and yield of tomato plants. Therefore, on the basis of assessment of results it can be postulated that nano-TiO 2 at the rate of 20 mg LG 1 proved best in enhancing growth, yield and quality of tomato.