Stimulation of Somatic Embryogenesis in Carrot by Ethylene

Abstract

In apparent contrast to findings of other workers, endogenous ethylene levels were suboptimal for somatic embryogenesis in a suspension culture of carrot. Low concentrations (≤0.5 mg 1−1) of ethephon caused statistically significant increases in ethylene (≤3 fold) and embryo formation (≤50%) whereas higher concentrations increased ethylene still further and inhibited embryogenesis. 1-Aminocyclopropane-1-carboxylic acid (ACC) in most experiments stimulated embryo and plantlet formation (up to 4 fold) but was inhibitory above 50 μM. The hypothesis that 2,4-dichlorophenoxyacetic acid (2,4-D) and other auxins inhibit embryogenesis by stimulating the production of ethylene cannot hold in systems that are suboptimal with respect to ethylene. Consistent with this, difluoromethylornithine (DFMO), which counteracts the inhibition by 2,4-D of somatic embryogenesis in carrot, did not counteract the inhibition by high concentrations of ethephon or ACC.KeywordsSomatic EmbryoSomatic EmbryogenesisEthylene ProductionAnther CultureEthylene LevelThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.