Effect of Nitric Oxide and Hydrogen Peroxide on Adventitious Root Development of Marigold

Effect of nitric oxide(NO) and hydrogen peroxide(H2O2) on adventitious root development of marigold(Tagetes erecta L.) and their interrelationship were studied.Results showed that exogenous NO-donor-sodium nitroprusside(SNP) and H2O2,had significant positive effect on adventitious root development,and the effect was dose-dependent with a maximal biological response at 200 μM for H2O2 and 50 μM for SNP.The root number and length of explants treated with both H2O2 and NO were significantly higher than those of explants treated with H2O2 or NO alone.NO is essential for H2O2-induced rooting,and H2O2 is also involved in NO-induced rooting.NO treatment enhanced H2O2 levels in cells of explants hypocotyls,simultaneously external application of H2O2 induced NO generation in cells too.Thus,H2O2 and NO may act synergistically to mediate adventitious root generation of the explants and they may enhance each other's levels by their mutual amplification in that process.