Effects of Multi Walled Carbon Nanotubes and Nano-SiO₂ on Key Enzymes for Seed Germination and Endogenous Hormone Level in Maize Seedling

Abstract

Nanotechnology can improve crop yield and quality by improving seed germination and growth conditions. We chose multi walled carbon nanotubes (MWCNTs) and nano silica (nano-SiO2) for exploring the effects of different concentrations of MWCNTs and nano-SiO2 on key enzymes for germination and endogenous hormone level in maize. The results indicate that MWCNTs and nano-SiO2 can promote seed germination characteristics, such as the germination potential, germination rate, germination index, storage material transport rate, radicle and germ biomass of maize seeds. Amounts of 800 mg·L−1 MWCNTs and 1500 mg·L−1 nano-SiO2 showed a positive effect on germination index, and nano-SiO2 was better than MWCNTs in promoting germination effects. Most importantly, MWCNTs and nano-SiO2 can improve the activities of amylase in maize grain, cytochrome oxidase (COX) and alternating oxidase (AOX) in seed embryo and key enzymes of glycolysis, so as to accelerate the hydrolysis of carbohydrates such as starch, provide energy and material basis for seed germination, improve seed vitality and promote seed germination. MWCNTs and nano-SiO2 can enhance the content of key hormones in promoting roots and leaves, including decreased content of abscisic acid (ABA) and increased contents of methyl jasmonate (MeJA), auxin (IAA), gibberellin (GA), and zeaxanthin (ZR), which result directly in achieving an available balance of MeJA/ABA, GA/ABA, ZR/ABA, and IAA/ABA ratios between different hormone contents, providing support for the growth development of maize kernels and seedlings.

Keywords

• maize
• multi walled carbon nanotubes
• nanoparticles SiO₂
• seed germination
• endogenous hormone level