1. Editorial

   • D. James Morré

   EditorialNotes Pages: iii - iv

2. Golgi apparatus buds — vesicles or coated ends of tubules?

   • D. J. Morré
   • T. W. Keenan

   OriginalPaper Pages: 1 - 4

3. Microtubules are involved in maintaining the cellular polarity in pollen tubes ofNicotiana sylvestris

   • Ute Joos
   • J. van Aken
   • U. Kristen

   Original Papers Pages: 5 - 15

4. Mitotic disrupter herbicides act by a single mechanism but vary in efficacy

   • J. C. Hoffman
   • K. C. Vaughn

   Original Papers Pages: 16 - 25

5. Redox-state of intactNitella cells: dependency on intracellular pH and photosynthesis

   • G. Thiel

   Original Papers Pages: 26 - 33

6. Vacuolar ion currents in the primitive green algaEremosphaera viridis: The electrical properties are suggestive of both the Characeae and higher plants

   • K. W. Linz
   • K. Köhler

   Original Papers Pages: 34 - 45

7. Structural and immunocytochemical characterization of microtubule organizing centers in pteridophyte spermatogenous cells

   • J. C. Hoffman
   • K. C. Vaughn
   • H. C. Joshi

   Original Papers Pages: 46 - 60

8. Variation in velocity of cytoplasmic streaming and gravity effect in characean internodal cells measured by laser-Doppler-velocimetry

   • D. Ackers
   • Z. Hejnowicz
   • A. Sievers

   Original Papers Pages: 61 - 71

9. Spread of beet necrotic yellow vein virus in infected seedlings and plants of sugar beet (Beta vulgaris)

   • F. Dubois
   • R. S. Sangwan
   • B. S. Sangwan-Norreel

   Original Papers Pages: 72 - 82

10. Dedifferentiation and microtubule reorganization in the apical cell protoplast ofSphacelaria (Phaeophyceae)

    • Anne-Marie Rusig
    • H. Le Guyader
    • G. Ducreux

    Original Papers Pages: 83 - 94