Effect of short-chain fatty acids on the ethylene pathway in embryonic axes of Cicer arietinum during germination

The effect of short-chain saturated fatty acids (C₅–C₁₀) on the biosynthesis of ethylene in embryonic axes of chick-pea ( Cicer arietinum L.) seeds was investigated. The emergence of radicle and fresh weight of embryonic axes diminished with increasing number of carbons. The inhibition of germination caused by lower concentrations (1 m M ) of fatty acids (C₅–C₁₀) was partially reversed by exogenous 1-aminocyclopropane-1-carboxylic acid (ACC), whereas exogenous ethylene was able to overcome the inhibitory effect provoked by all concentrations (1–5 m M ) of applied fatty acids (C₅–C₁₀). Ethylene production rates, and enzyme activities of ACC synthase and ACC oxidase decreased concomitantly with the molecular mass and increasing concentration of fatty acids. The inhibitory effect of these acids on ethylene production seems to result not only from a decreased ACC synthesis, but also from an enhancement of 1-malonylamino)cyclopropane-1-carboxylic acid (MACC) synthesis.