Nano-urea as a potential substitute for ammonium nitrate in the tissue culture medium for micropropagation of banana

Abstract:

The banana (Musa spp.) tissue culture industry plays a vital role in sustainable agriculture by enabling large-scale production of disease-free and genetically uniform plantlets. However, reliance on ammonium nitrate as the primary nitrogen source in the tissue culture medium presents logistical and regulatory challenges due to its use in explosives. This study investigates the efficacy of nano-urea (4-5 % nitrogen), a nanotechnology-based, slow-release, nitrogen fertilizer as an alternative to ammonium nitrate in banana micropropagation. Cultures grown on medium supplemented with nano-urea at 2 mL L^-1 (T₅) without ammonium nitrate exhibited similar growth to the control medium containing ammonium nitrate, with comparable shoot number, shoot length, and leaf parameters. In contrast, higher concentrations of nano-urea negatively affected shoot proliferation and delayed shoot initiation. Correlation and principal component analysis revealed strong positive relationships among vegetative traits, while days to shoot initiation was negatively associated with overall growth. Preliminary gene expression analysis of nitrogen uptake-related genes (MaAMT, MaNRT2, and MaNRT) suggests that nano-urea at optimal concentration was associated with increased MaNRT (nitrate transporter) transcript abundance, while reducing MaNRT2 transcript abundance, whereas MaAMT (ammonium transporter) expression remained largely unchanged. These results demonstrate that nano-urea can partially substitute ammonium nitrate in banana tissue culture medium, although the concentration of nano-urea needs to be carefully optimized to avoid adverse effects. To the best of our knowledge, this is among the first reports exploring the use of nano-urea in tissue culture medium, offering a novel and potentially more sustainable alternative for in vitro plant production systems.

Cite