Fig. 1. The effect of nZnO on germination and primary root length. (a) The germination of
peas on the third day after exposure to nZnO for 24 h. (b) The primary root length of peas
grown in vitro for 4 successive days, after imbibition in solution containing nZnO2 for 24 h.
Starting on the 3rd day, the root length was determined daily until the 6th day. Nano-ZnO
did not have significant effect on germination rate, whereas it had remarkable effect on
root length (⁎⁎⁎: p b 0.001).