Changes in polyamine levels in relationship to the growth and development of parthenocarpic fruits (shotberries) of olive (Olea europaea L.)

The effects of applied polyamines (PAs), putrescine (Put) and spermidine (Spd) on parthenocarpic fruits (shotberries) and fruit set of olive were assessed. Factorial experiments were conducted in a randomized complete block design with three replications. Putrescine at 2.5 and 5 mM.l−1 and spermidine at 1.25 and 2.5 mM.l−1 were sprayed on branch units on olive trees (Olea europaea L. cv. Fishomi) at full bloom (FB) and two weeks after full bloom (2WAFB). The number of normal fruits and shotberries were evaluated. Endogenous PAs in the mesocarp and seeds were determined at both times of PAs application until fruit maturity. The results showed that Put was very effective in decreasing the percentage of the shotberries and increasing the percentage of normal fruits when PAs applied at FB. Mesocarp had the highest Put content in Put at 5 mM.l−1 and Spd at 2.5 mM.l−1 treatments respectively. In seed, the highest PAs content was found in Put treatment at 5 mM.l−1 and the highest Spm and Spd content was observed in Spd treatment at 2.5 mM.l−1.