In this research, the effects of a various in concentration of TiO 2 nanoparticles (Nano-TiO 2 ) were applied to study the cell growth, metabolites and antioxidant responses of callus in indica rice plants.Dose-dependent changes in growth performances, metabolite accumulations and antioxidant activities of callus were found.Mature seeds of indica rice cv.Pathumthani1 were cultured in callus induction medium with different concentrations of Nano-TiO 2 (0-600 mg L -1 ).After five weeks of cultivation, the callus formations were measured in fresh weights and dry weights, and the contents of phenolic compounds, flavonoids, and the antioxidant activities of callus extracts were assayed.The Nano-TiO 2 induced of fresh weights and dry weights in callus formations when compared with the control treatment (0 mg L -1 Nano-TiO 2 ) were also observed.The flavonoid and phenolic compound contents in rice callus exposed to 400 mg L -1 Nano-TiO 2 were 118% and 139%, respectively, higher than rice callus unexposed to Nano-TiO 2 .Moreover, the antioxidant activities of the callus metabolites studied shows that the percentages of inhibition were up-regulated (84%) when exposed to 400 mg L -1 Nano-TiO 2 , as a response to the highlevel depletion of the free radicals in metabolites of rice callus.The results obtained from this research showed that the addition of Nano-TiO 2 had impacts on the callus growth and metabolite accumulations in rice callus.The results suggested that addition of Nano-TiO 2 at appropriate levels could role as an elicitor for biosynthesis of valuable metabolites and antioxidant properties for pharmaceutical applications in further research.

Introduction – Mexico is one of the leading producers and exporters of mangoes worldwide. Nevertheless, local producers' selection and breeding practices have resulted in the development of varieties not cultivated commercially. However, the sensory value of these varieties has meant they have been preserved and are produced on a smaller scale. This study evaluated morphological and physicochemical changes of four varieties cultivated in Chiapas, 'Ataulfo', 'Manililla', 'Oro' and 'Tommy Atkins'. Materials and methods – The physicochemical (moisture, ash, proteins, total soluble solids, pH, and titratable acidity) and morphological changes during the ripening of mango from Chiapas, Mexico, were described according to the IPGRI guide. The study was conducted using a completely random design in a factorial scheme, the first factor variety ('Ataulfo', 'Manililla', 'Tommy Atkins' and 'Oro') and the second maturity stage (physiological and consumption maturity). Results and discussion – The average weights of ripe fruits were 252, 185, 269 and 653 g, for 'Ataulfo', 'Manililla', 'Oro' and 'Tommy Atkins', respectively, while their pulp content was 82, 77, 73, and 84%. 'Ataulfo' contained the highest total soluble solids (21%), followed by 'Tommy Atkins' (18%), 'Manililla' (16%) and 'Oro' (13%). Conclusion – The mango varieties named 'Ataulfo' and 'Tommy Atkins' have been found to have better pulp quality (% of fruit, °Brix), making them ideal for commercial use. On the other hand, the varieties 'Manililla' and 'Oro' have a desirable proportion of pulp and peel, making them suitable for use in the concentrate and beverage industries.