Exploiting the potential of bio-synthesized silver nanoparticles to enhance the shelf life of Gladiolus

Gladiolus spikes with fully turgid petals need to have a longer shelf life to fetch a higher price as well as display value. To improve the life duration of ornamental flowers, the ability of plants to produce silver nanoparticles (AgNP) was exploited. The ability of plants to produce AgNP when treated with silver nitrate solutions was juxtaposed by using Gladiolus (cut flowers): (i) To find the appropriate concentration of AgNO3 suitable for increasing shelf-life of Gladiolus cut flowers; (ii) To prepare silver nanoparticle from AgNO3; and (iii) To confirm the formation of silver nanoparticle using UV-vis spectrophotometry. Two different reductants (dehydrogenases present at the surface of the plant cells and sucrose) demonstrated the reduction of Ag+ to generate AgNPs. DLS (Dynamic Light Scattering) study revealed the presence of NPs in the AgNO3 salt solution incubated with Gladiolus cut flowers. The DLS data also suggested that the size of AgNPs decreased with increasing concentration of AgNO3. In the present study, along with silver nitrate, sucrose was also used. The shelf life and display value of the cut Gladiolus can be increased and optimized by incubating it in sucrose solution in combination with AgNO3.

Roots of Pennisetum sp. possess the competence to generate nanoparticles of noble metals

Roots of plants have immense reducing potential. Ions of noble metals namely Au3+ and Ag+ get reduced easily to form Au and Ag nanoparticles (NPs), respectively. Therefore, we hypothesize that plant roots could have potential to form Au-NPs and Ag-NPs. For present investigations, plants of Pennisetum glaucum L. were used to evaluate if their roots possess capacity to generate metal NPs. The generation of Au-NPs and Ag-NPs was initially presumed based on colour change, and confirmed by UV-vis spectra, TEM and EDX investigations. Pale yellow Au3+ and colourless Ag+ solutions turned purple and brown, respectively, by roots of Pennisetum sp. within 8 h. Absorption spectra of respective solutions showed plasmon resonance band at 560 nm and 420 nm confirming the presence of Au-NPs and Ag-NPs. TEM coupled with SAED revealed the presence of crystalline spherical NPs in the size range of 5-50 nm in these solutions. EDX further confirmed the presence of Au and Ag as NPs of respective solutions. These results confirmed that the roots of P. glaucum possess ideal reducing strength to generate Au-NPs and Ag-NPs exogenously in the aqueous phase.