Histological studies on flower abortion in olive cultivars

Two main categories of olive flowers were characterized. The first by presence of normal gynoecium and the other by the presence of rudimentary gynoecium. Complete flowers differed in shape of ovaries, style length, shape of stigma and density of hairs covering the stigma. Three types of aborted flowers were observed. The first type could be detected by lack of ovule integuments. The second by undevelopment of the style, outer tissues of the ovary and of the ovules, while the third comprised flowers of completely undeveloped female organs. No correlation existed between pistil abortion and the viability of pollen grains. Four groups of pollen grains regarding their stainability and three groups according to their shape were detected.