Involvement of Nitric Oxide Synthesis in Ethylene-Induced Stomatal Closure of Vicia faba

The abaxial epidermis of Vicia faba is employed as materials,both 1-aminocyclopropane-1-carboxylic acid(ACC),an immediate precursor of ethylene synthesis and ethylene gas significantly induced stomatal closure by means of stomatal bioassay and using laser-scanning confocal microscopy based on the NO-sensitive probe 4,5-diaminofluorescein diacetate(DAF-2 DA).Moreover,ACC and ethylene gas induced stomatal closure in a dose-dependent manner.Additionally,NG-nitro-L-arginine methyl ester(L-NAME),an inhibitor of NO synthase(NOS),obviously inhibited ACC-and ethylene gas-induced stomatal closure and NO production,indicating a requirement of NOS-like enzyme-dependent-NO synthesis for stomatal closure by ethylene,which suggests that ethylene induces stomatal closure via causing NO synthesis.