Multi-walled carbon nanotubes interact with light intensity to affect morpho-biochemical, nutrient uptake, DNA damage, and secondary metabolism of Stevia rebaudiana.

Abstract

In this study, the interaction between nanoparticles (0, 50, 100, and 150mg L-1) and light intensity (100, 200, and 400μmol·m-2·s-1) was evaluated for effectiveness in improving stevia shoot induction by measuring morphological traits, nutrient absorption, total carbohydrates, steviol glycosides (SVglys), and DNA damage in two DNA sequence regions (promoter and sequence of the UGT76G1 gene). MWCNTs at a concentration of 50mg L-1 in interaction with the light intensity of 200μmol·m-2·s-1 improved the morphological traits and absorption of nutrients such as nitrogen (N), phosphorous (P), potassium (K), calcium (Ca), iron (Fe), and Manganese (Mn), compared to other treatments. Also, under this interaction, the accumulation of total carbohydrates and SVglys was elevated. Moreover, DNA damage in both regions of the DNA sequence under light intensity at low concentrations of MWCNTs (0 and 50mg L-1) did not show a significant change but increased with increasing MWCNT concentration at high light intensities (200 and 400μmol·m-2·s-1). These results demonstrate that the advantages and phytotoxicity of MWCNTs in the in vitro culture of stevia are dose-dependent and are affected by light intensity. Based on this, the interaction of 50mg L-1 of MWCNTs with the light intensity of 200μmol·m-2·s-1 is recommended to improve stevia micropropagation and subsequent growth and metabolism.