Reproductive cycle of Pistacia lentiscus (Anacardiaceae) in Southern Italy

Abstract

ABSTRACT The reproductive cycle of Pistacia lentiscus L. from southern Italy is described with special emphasis on phenology and reproductive success. The species flowers in spring, its fruits ripen in autumn and has a latent ovary period during the summer. Vegetative growth starts immediately after anthesis (end of March) and finishes by the second week of June. Bud sections showed that flower induction occurred a few weeks after shoot development. However, no change in the overall appearance of the buds was noticeable before the following spring. Flowering is very synchronous within a plant, and a clear overlap in the flowering times of the two sexes occurred in the population studied. Although P. lentiscus seems to be highly reproductive because of the numerous fruits generally found on the plants in autumn, its reproductive success (as percent of flowers which develop fruits with seed) is low. Very large numbers of flowers never develop fruit and drop at different stages during fruit development. Moreover, numerous fruits have no seed because of parthenocarpy, embryo abortion or insect damage. In P. lentiscus, low reproductive success is not uniform within the population because the number of empty fruits per plant is highly variable between the plants. Our observations suggest that rain at flowering can make pollination a limiting factor for fruit set because of the reduction in the quantity of available pollen. Since these results are in agreement with those reported for populations in Israel and Spain, such phenomena could be genetically determined, and therefore common to this species throughout the Mediterranean region.