ULTRASTRUCTURAL-STUDY OF MATURING POLLEN IN ARABIDOPSIS-THALIANA (L) HEYNH (BRASSICACEAE)

Ultrastructural changes in Arabidopsis thaliana pollen, between late m icrospore stage and mature pollen stage were described. When the gener ative cell was peeled off from the intine, it was of spherical shape a nd had all usual organelles with the exception of plastids. The cytopl asm transformation of the vegetative cell included an increase in the number of mitochondria and changes in the accumulation of starch and l ipid bodies. The starch plastids were observed at the bicellular and e arly tricellular pollen stages and next starch was utilized during the maturation process. The lipid bodies of the vegetative cell form a ve ry regular sheath around the generative cell and then, around the sper m cells. Before anthesis the lipid bodies were dispersed within the wh ole vegetative cell cytoplasm.