Advances on the Study of Sexual Reproduction in the Cork-Tree (Quercus suber L.), Chestnut (Castanea sativa Mill.) and in Rosaceae (Apple and Almond)

Research in sexual plant reproduction has been boosted by the concentration of means and minds around central issues, such as incompatibility, microspore development or, to a less extent, the progamic phase of fertilisation. These areas are now pivotal since they involve basic biological questions still unanswered and which became recently accessible due to powerful genetic and molecular techniques. While these combined efforts resulted in the outcome of major findings that projected the field to a place not easy to by-pass even in the general context of Biology, this was only possible because of the existence of a few model species, particularly adapted to the experimental needs of the molecular weaponry. Most notably, Arabidopsis now plays a central role, since it possesses most of the development paths that characterise the majority of Angiosperms (with the exception of secondary growth). While this approach is not questionable, since it permits a faster advance in models and concepts, the reductionism underlying the focus on a few model species may create a void of knowledge on the natural variability and diversity of the cellular and molecular mechanisms. Most likely, the majority of the flowering species will never find their place as models species since they cannot compete as regards easiness to grow, maintain and analyse. Yet, an historical perspective shows beyond doubt that some of these species may bear variations to the basic models which may open new avenues and question established paradigms. Such was the case of Arabidopsis, for instance, often neglected and rejected for funding because of its condition of weed (Goldberg 1996).