Ultrastructure of Vegetative and Reproductive Apices of Chenopodium album.

The apical meristem of the vegetative shoot of Chenopodium album (lamb's-quarters) exhibits alterations in cytoplasmic structure as early as 3 hours after the plant has been subjected to one photoinductive cycle which promotes flowering. The endo-plasmic reticulum shows an altered distribution and there is evidence of an increase in acid phosphatase production. Dictyosomes increase in number per cell by the end of the second inductive cycle.