ZNO AND TIO2 NANOPARTICLES STIMULATE CALLUS INDUCTION AND SECONDARY METABOLITE PRODUCTION IN Indica RICE.

Metal nanoparticles are widely used in various fields of industry and their impact in the agricultural field is increasing. This research was carried out to investigate the effects of ZnO and TiO2 nanoparticles on callus induction and plant metabolism in indica rice. Indica rice was assessed in plant tissue culture condition to estimate the influence of metal nanoparticles on morphological and physiological factors over 4 weeks. The seeds of Oryza sativa L. var. KDML105 were exposed to 1-3 mg L-1 of 2,4-dichlorophenoxyacetic acid (2,4-D) in the callus induction medium. The induced-calli were cultured on the callus induction medium supplemented with 2 mg L-1 of 2,4-D and showed a high increase in size and dry weight contents under the light condition when compared with the control and other treatments. Moreover, this research also investigated the potential impacts of ZnO and TiO2 nanoparticles at 200, 400 and 800 mg L-1 on morphological and metabolic responses of the induced-calli cultured on the callus induction medium supplemented with 2,4-D and each type of metal nanoparticles. At 4 weeks after treatment, the induced-calli were analyzed for plant growth and assays on aspects of their metabolism were undertaken. The induced-calli exposed to 200 mg L-1 of ZnO or TiO2 nanoparticles were found to have significant increase of biomass (size and dry weight of callus), total phenolic compounds and total flavonoid contents in KDML105 variety. The results demonstrated that utilization of ZnO and TiO2 nanoparticles at appropriate concentration could positively induce the production of beneficial secondary metabolites in the induced-calli of indica rice and are worthy of further study for applications in other plant species. [ABSTRACT FROM AUTHOR]