Morphological characterisation of wheat (T-aestivum L.) egg cell protoplasts isolated from immature and overaged caryopses

The morphological features and fine structure of wheat egg cell protoplasts isolated from premature (3 days prior to anthesis) and overaged (12 days a fter anthesis) caryopses were compared. Except for shape, the young egg cel l protoplast showed the same morphological characteristics as the egg cell in planta at the time of anthesis. Young and adult egg cell protoplasts wer e spherical in shape. Polarity could not be identified exactly with the met hods used. During aging, the egg cell increased considerably in volume. The adult egg showed the typical features (membrane blebbing, autophagous vacu oles) of programmed cell death. It appears that after a long life-span (abo ut18 days) cells of the female gametophyte undergo apoptosis.