Silicon Nanoparticles Mediated Increase in Glandular Trichomes and Regulation of Photosynthetic and Quality Attributes in Mentha piperita L.

Interest in the use of the nanoparticles as plant growth elicitors mushroomed within the last decade and the field is quite intriguing to meet the growing needs of the burgeoning population. Peppermint is a plant of considerable importance to the traditional as well as modern medical world primarily because of its essential oil (EO). In view of the beneficial effects of silicon (Si) in plants and the substantial pharmaceutical importance of peppermint, the present study was designed to investigate the influence of silicon nanoparticles (SiNPs) on some of the photosynthetic and yield parameters of the plant as the nanoparticles are edged over the normal elemental forms due to some unique physico-chemical characteristics. A simple randomized experiment was designed and the treatments included: foliar spray of de-ionized water only (control), and foliar spray of SiNPs with 50, 100, 150, and 200 mg L-1. Lower concentrations of SiNPs (50 and 100 mg L-1) proved significant (P <= 0.05) for most of the parameters studied and increased the peltate glandular trichome density and diameter significantly. An increase of 11.5% was reported in chlorophyll content while chlorophyll fluorescence increased by 6.8%, net photosynthetic rate by 21.1% and total phenol content by 11.9% at 150 days after plantation (DAP). EO content exhibited an increase of 26.5%. While menthol content was increased by 8.85%, menthone and menthyl-acetate contents were decreased by 2.2% and 10%, respectively at 150 DAP.