Ovular secretions as part of pollination mechanisms in conifers

Conifers have a diversity of pollination mechanisms that assist in the capture of pollen during pollination. Pollination mechanisms can be divided into a number of general types depending on whether they have an ovular secretion that interacts with the pollen. These types include mechanisms that never have a secretion, or those that have a delayed secretion, or the most common type in which a pollination drop is formed. This review outlines the evolutionary context of ovular secretions, describes the origins of these secretions within the ovule, their function in the two types of pollination mechanisms, and details the biochemical composition of these liquids. Not only do ovular secretions provide a germination medium for pollen, but they may also play a significant part in reducing pollen pollution by foreign species. pollination mechanism / conifer / ovular secretion / pollination drop Rsum -Les scrtions ovulaires : leurs rles dans les mcanismes de pollinisation des conifres. Les conifres possdent divers mcanismes de pollinisation qui aident la capture des grains de pollen lors de la pollinisation. Ces mcanismes peuvent tre classs en quelques types gnraux selon qu'une scrtion ovulaire interagissant avec le pollen existe ou non. Ces diffrents types comprennent des mcanismes sans scrtion, avec scrtion retarde ou, et c'est le type le plus rpandu, avec formation d'une goutte de pollinisation. Cet article dcrit le contexte de ces secretions en terme d'volution, leurs origines ovulaires, leurs fonctions dans les deux types de mcanismes de pollinisation, et leur composition biochimique. Les scrtions ovulaires non seulement fournissent un milieu favorable la germination du pollen, mais peuvent aussi diminuer de faon importante la pollution pollinique due des pollens trangers.