XVI International Botanical Congess

Major stages in nuclear endosperm development are: initiation and proliferation of peripheral syncytium, organization of syncytium into nuclear-cytoplasmic domains (NCDs) by nuclear-based radial microtubules, polarization of NCDs with rearrangement of radial arrays into axial arrays, alveolation by free growing anticlinal walls which continue to grow centripetally in association with adventitious phragmoplasts, periclinal division in the alveoli resulting in a peripheral cell layer and an inner layer of alveoli. Repeated rounds of alveolar growth followed by periclinal divisions completes cellularization except in the chalazal tip where a syncytial cyst remains.