The association between low temperatures and anatomical changes in preanthetic ovules of Musa (Musaceae)

The ovules affected by low temperature were smaller, grew less between developmental stages and remained more round towards anthesis than those that were unaffected. Affected ovules had smaller female gameotphytes that occupied a reduced proportion of the nucellus. In addition, the distance between the embryo sac and the nucellar cap increased, however the number of intervening cells did not. The nucellar cells in the tongue were squashed longitudinally. Malformations of ovules were observed in bunches emerging in the autumn and winter as well as spring, associated with low temperatures at a critical period in the few weeks before anthesis when the archesporia and megaspore were formed.