Number of somatic embryos [expressed as a percentage of WT control (ctrl)] collected from the WT, Glb1 RNAi and Glb2−/− mutant lines treated with increasing levels of NO donor sodium nitroprusside (SNP) (A), the NO scavenger 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (cPTIO) (B), the ethylene releasing agent Ethephon (ETH) (C), and the ethylene biosynthetic inhibitor O-(carboxymethyl)hydroxylamine hemihydrochloride) (AOA) (D). Compounds were added in the induction medium. Values are means ± SE of at least three biological replicates.