The anatomy of ovule ontogeny of banana, plantain and enset (Musaceae)

Ovules of the seeded diploid Musa acuminata (AA) and seedless edible triploids (AAA) from the same cytogenetic group, plus edible triploids of the Musa balbisiana cytogenetic group (AAB and ABB), were studied to determine their development before and past anthesis. Of particular interest was the development of the embryo sac and whether the growth of reproductive tissues in the parthenocarpic fruit (edible triploids) differed from the fertile seeded fruit (diploids). Ovules were collected from 18 cultivars and species growing in subtropical northern New South Wales and the Mediterranean climate of Perth, Western Australia. Ovules were examined histologically using the light microscope. The development of the triploid ovules was similar to the diploid ovules. The anatomical development of ovules of seeded diploid, edible triploids, tetraploids and the related genus Ensete sp. under went similar, if not identical, patterns of ontogeny. The most distinctive difference in ovule ontogeny between members of musaceae is ovule size, ensete ovules were significantly larger than other members of the family. Parthenocarpic edible triploids and tetraploids, of A and B genome and sub species of M. acuminata (Musa a. ssp.) had anatomically mature ovules that contained embryo sacs at anthesis. Some of these embryo sacs had one or more nuclei. Some had eight nuclei, even in the highly sterile Cavendish subgroup. Thus, ovule fertility should be investigated as part of an integrated reproductive system.