Abstract: Generative cells in pollen of Citrullus lanatus were characterized ultrastructurally as they round out.Organelle rearrangement occurred in response to cell's rounding out.Organelles in nascent cells were distributed randomly.As rounding out,however,the cells showed polarity,extensively abundant endoplasmic reticula and very sparse mitochondria in the region near pollen wall,while much less endoplasmic reticula and a lot more copious mitochondria in the other side towards pollen center.The cell's rounding provides an insight into the mechanism for cell's departure from pollen wall.Nucleus showed deep invaginations where endoplasmic reticula and ribosomes were distributed.