Precipitation of Ag+ as AgCl in agar gel medium occurs due to the presence of HCl as a contaminant. If an excess of AgNO3 is added to this broth, only then free #EVP4593 randurls[1|1|,|CHEM1|]# Ag+ ion will be available which may be reduced to nanosized particles. However, contrary to the present report, both the AgNO3 and Ag2S2O3 will furnish Ag+ ions which will have the same influence on the root growth, if the effect of and ions is ignored [71]. In this work [65], the Ag2S2O3 was prepared by mixing 0.1 M solutions of AgNO3 and Na2S2O3 in 1:4 M ratio at ambient temperature. Since, according to the simple metathetical reaction as given below, the two components react in 2:1 M ratio, there is always an excess

of Na2S2O3 in this preparation. Silver nanoparticles may be present with large crystal (three to five times) of Na2S2O3 and hence the influence of ions on the shoot growth may be ignored. The development of root by Ag+ ion (obtained from AgNO3) in the presence of Cl- ion is shown, which was obtained from Ag2S2O3 [65]. It is to be made clear that if the chloride ion is present in the solution, the entire AgNO3 will be precipitated and no free Ag+ ion will be available to exhibit its influence on root growth. If AgNO3 is in large excess and there is only little Cl- ion available, some of it will be available as free ions. Dorsomorphin The silver ions may be available for interaction with other molecules. However,

it is important to note that when AgNO3 is taken in the presence of Na2S2O3, the Ag2S2O3 thus formed remains dissolved, and both the Ag+ and ions are available. The cumulative effect of both the Ag+ and ions on root development may be encountered. To eliminate the effect of ion, similar experiment, only with Na2S2O3 mediated with IBA showed that the concentration of Na2S2O3 above 100 μm was most effective [65]. Song and Kim [21] have reported the synthesis of silver nanoparticles using the leaf extract of five

different plants, namely pine, persimmon, PR-171 mw ginkgo, magnolia and platanus. Of all the five leaf extracts, magnolia leaf broth was found to be the most effective reductant for silver nitrate to silver nanoparticles. The process of production of nanoparticles was so fast that nearly 90% of Ag+ ion was converted to silver metal in about 11 min at 95°C. The average particle size ranges between 15- and 500 nm. The authors have observed that the size of the particles can be monitored by (i) changing the temperature and (ii) the concentration of AgNO3 and (iii) that of the leaf extract. It has already been studied that the particle size of the nanocrystal decreases with the increase in reaction temperature. Song and Kim [21] have hypothesized that with increasing temperature the rate of reduction of Ag+ ion to Ag also increases, stopping the secondary reduction process on the surface.