An investigation was initiated to examine the effects of nanoscale zinc oxide particles on plant
growth and development. In view of the widespread cultivation of peanut in India and in other
parts of the globe and in view of the potential influence of zinc on its growth, this plant was chosen
as the model system. Peanut seeds were separately treated with different concentrations of nanoscale
zinc oxide (ZnO) and chelated bulk zinc sulfate (ZnSO4) suspensions (a common zinc supplement),
respectively and the effect this treatment had on seed germination, seedling vigor, plant growth,
flowering, chlorophyll content, pod yield and root growth were studied. Treatment of nanoscale ZnO
(25 nm mean particle size) at 1000 ppm concentration promoted both seed germination and seedling
vigor and in turn showed early establishment in soil manifested by early flowering and higher leaf
chlorophyll content. These particles proved effective in increasing stem and root growth. Pod yield
per plant was 34% higher compared to chelated bulk ZnSO4. Consequently, a field experiment
was conducted duringRabiseasons of 2008–2009 and 2009–2010 with the foliar application of
nanoscale ZnO particles at 15 times lower dose compared to the chelated ZnSO4recommended and
we recorded 29.5% and 26.3% higher pod yield, respectively, compared to chelated ZnSO4.The
inhibitory effect with higher nanoparticle concentration (2000 ppm) reveals the need for judicious
usage of these particles in such applications. This is the first report on the effect of nanoscale particles
on peanut growth and yield.