Germination of olive seeds (Olea Europaea L) and ethylene production: effects of the harvesting time and thidiazuron treatments

The germination of mature seeds of olive (Olea europaea L.) from six cultivars was examined by recording the percent germination, rate of germination and the ability to produce ethylene. The effects of various treatments, namely thidiazuron (TDZ), a compound with cytokinin-like activity, 1-aminocyclopropane-1-carboxylic acid (ACC), and aminoethoxyvinylglycine (AVC), on these variates were also evaluated. The main characteristics of seed development were also defined in both 'Moraiolo' and 'Canino', following harvest on three dates, by determining the course of the dehydration process and the ability of the seeds to produce ethylene; the effect of maturity state on germination and ethylene production was clarified. In general, there were wide variations between the cultivars with no positive correlations between the examined parameters. Germination of untreated seeds (control) from all the cultivars was always accompanied by an increase in ethylene synthesis. The presence of ACC was not always effective in a concomitant stimulation of germination and ethylene production. Instead, TDZ influenced the germination process in almost all the cultivars even if it did not always enhance ethylene production. In all cultivars tested, the presence of AVG in general reduced the stimulatory effect of TDZ on the percent germination and on ethylene production. The findings are discussed in relation to the possible role of ethylene production in the germination of olive seeds.