Electron-microscopy on anther tissue and pollen of male sterile and fertile wheat (Triticum aestivum L.)

Summary

1. Anther tissue and pollen grains of cytoplasmic male sterile and fertile wheat were studied with the aid of an electron-microscope for differences in cytoplasmic structures.

2. Clear and consistently occurring cytoplasmic differences were not observed, although unidentifiable particles were discovered in both the sterile and the fertile material.

3. Male sterility finds expression in the small number of organelles in the sterile pollen grains which consequently are little or hardly physiologically active and thus subject to a rather rapid degeneration. On the contrary the fertile pollen grains are full of cell organelles and therefore well equipped for a complete development.

4. The fertile pollen grain contains a clear intine which is thicker than the exine. Only a very thin intine was observed in the sterile material.

5. Male sterility has no visible influence on exine formation. Ubisch bodies occur in the anthers of both male sterile and fertile plants. There is no sign of any contribution to exine formation on the part of the Ubisch bodies. There was more evidence of exine formation from within than from without. The normality of exine formation of sterile pollen grains need not indicate exine formation from without; it suggests rather that exine is largely formed before degeneration.