Evaluation of nano-silicon efficiency on compatible solutes and nutrient status of Damask rose affected by in vitro simulated drought stress

Background Drought stress is a critical environmental factor that disturbs plant performance. However, some non-essential elements such as silicon can improve water deficit tolerance by modulating photosynthesis assimilates and compatible solutes production. Therefore, the present work was conducted to modulate polyethylene glycol (PEG)-induced water deficiency under in vitro culture in Damask rose genotypes (Maragheh and Kashan) by nano-silicon (SiO 2 -NPs) treatment. A completely randomized factorial experiment was used as three concentrations of SiO 2 -NPs (0, 50, and 100 mg L −1 ) and five concentrations of PEG (0, 25, 50, 75, and 100 g L −1 ). Then, the comparative effects of water deficiency on vegetative traits, metabolites, and nutrients were studied. Results The drought promoted a significant decrease in chlorophyll, fresh/dry weight, biomass, and an increase in electrolyte leakage. The amount of micro- and macronutrients were affected by drought stress and decreased in both genotypes. In contrast, the activity of polyphenol oxidase (PPO) and total phenolic compounds (TPC) along with biochemical traits was increased. Treatment with SiO 2 -NPs improved the leaf area index (LAI), chlorophyll, and biomass under severe water deficiency. The concentration of compatible solutes such as carbohydrates, total flavonoid content (TFC), TPC, anthocyanin, and antioxidative capacity enhanced by the application of SiO 2 -NPs by about twofolded. As well as an increase in PEG concentration, the absorption of nutritional elements such as P, K, Mn, Fe, Zn, and Cu was decreased. However, SiO 2 -NPs application especially at 100 mg L −1 increased the amount of nutrient absorption. Conclusions In general, the drought tolerance in Damask rose was associated mainly with its suitable manipulation of antioxidant production and orderly enhancement of nutrient adsorption, so that the effect of SiO 2 -NPs in improving the qualitative and quantitative characteristics of ʻKashanʼ was more than that of ʻMaraghehʼ. These results briefly highlight that the SiO 2 -NPs may provide greater tolerance to drought stress in Damask rose. Graphical Abstract