Investigation of the plant growth, photosynthetic pigments and antioxidant enzymes changes of aromatic rice treated with nano-TiO2

Abstract

The aim of this research was to determine the effect of nano-TiO₂ at different concentrations on the morphological and physiological response of aromatic rice (Oryza sativa L.). Khao Dawk Mali 105 rice cultivar (KDML105) were grown in NB medium supplemented with 100, 300, 500 and 1,000 mg L^-1 nano-TiO₂. Tissue culture grown seedlings were used to investigate morphological characterization (%germination, shoot length and root length parameters) and physiological characterization (photosynthetic pigments and antioxidant enzymes parameters) in rice seedlings during 5-14 days after treatment conditions. Rice seedlings treated with 100 and 300 mg L^-1 nano-TiO₂ were increased the %germination (1.01-1.07-fold), shoot length (1.03-2.05-fold) and root length (1.04-1.96-fold). Furthermore, the concentrations of photosynthetic pigments and the specific activities of antioxidant enzymes showed an increase of chlorophyll A (1.02-1.75-fold), chlorophyll B (1.07-2.10-fold) and carotenoids (1.10-1.87-fold) contents as well as catalase (1.05-1.35-fold) and peroxidase (1.11-1.79-fold) enzyme activities in rice seedling treated with 100 and 300 mg L^-1 nano-TiO₂ when compared with the untreated and treated with 500 and 1,000 mg L^-1 nano-TiO₂. The changes in the morphological characterization showed a positive correlation with the physiological characterization in rice seedlings treated with 100 and 300 mg L^-1 nano-TiO₂. The results indicated that the antioxidant enzyme system leads to more effective roles in plant protection against nanomaterials stress which enhance their morphological and physiological properties in plants.