Structural and ultrastructural characterization of maize coenocyte and endosperm cellularization.

摘要

Maize coenocytic and cellularizing endosperm development were characterized at optical and transmission electron microscopy levels. Samples were collected daily in 3 consecutive years under different temperature regimes; therefore, the developmental stages were expressed on a growing degree basis. Soon after the primary endosperm nucleus is formed, it starts dividing without cytokinesis, leading to the formation of the coenocyte. The nuclei divide freely on the periphery of the coenocyte and spread from the micropylar region toward the chalazal region. The first anticlinal walls are formed as the nuclei come closer to each other, followed by periclinal wall formation also starting in the micropylar region. As cellularization proceeds, new anticlinal and periclinal walls assume a less organized pattern until the central vacuole is fully occupied by newly formed cells. Overall, our findings suggest that the developmental pattern of maize coenocytic and cellularizing endosperm has many similarities to other species of the Poaceae family..