Promotion of ethylene biosynthesis in peach mesocarp discs by auxin

In this study, we investigated the ability of auxin to promote ethylene biosynthesis in fruit tissue. Discs prepared from preclimacteric peach fruit (Prunus persica L. Batsch cv. Akatsuki) were incubated for 3 weeks on a solid MS medium containing various concentrations of 1-naphthaleneacetic acid (NAA). Higher ethylene production was observed with an increasing concentration of NAA. As the developmental stage progressed, the time it took for the discs to produce ethylene became shorter and the amount of ethylene became greater. Auxin-induced ethylene production was effectively inhibited by adding 100 muM of CoCl2 to the medium. The stimulatory effect of auxin on anthocyanin formation was not affected by Co2+, although softening was inhibited, suggesting that the effect of auxin on softening is mediated by ethylene.