Abstract
Nanotechnology has become one of the several approaches attempting to ameliorate the severe effect of drought on plant's production and to increase the plants tolerance against water deficit for the water economy. In this research, the effect of foliar application of TiO(2), nanoparticles or ordinary TiO(2), on Helianthus annuus subjected to different levels of water deficit was studied. Cell membrane injury increased by increasing the level of water deficit and TiO(2) concentration, and both types of TiO(2) affected the leaves in analogous manner. Ord-TiO(2) increased H(2)O(2) generation by 67-240% and lipid peroxidation by 4-67% in leaves. These increases were more than that induced by Nano-TiO(2) and the effect was concentration dependent. Proline significantly increased in leaves by water deficit stress, reaching at 25% field capacity (FC) to more than fivefold compared to that in plants grown on full FC. Spraying plants with water significantly decreased the activities of enzymes in the water deficit stressed roots. The water deficit stress exerted the highest magnitude of effect on the changes of cell membrane injury, MDA, proline content, and activities of CAT and GPX. Nano-TiO(2) was having the highest effect on contents of H(2)O(2) and GPX activity. In roots, the level of water deficit causes highest effect on enzyme activities, but TiO(2) influenced more on the changes of MDA and H(2)O(2) contents. GPX activity increased by 283% in leaves of plants treated with 50 and 150 ppm Nano-TiO(2), while increased by 170% in those treated with Ord-TiO(2), but APX and CAT activities increased by 17-197%, in average, with Ord-TiO(2). This study concluded that Nano-TiO(2) didn't ameliorate the effects of drought stress on H. annuus but additively increased the stress, so its use in nano-phytotechnology mustn't be expanded without extensive studies. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s12298-022-01153-z.