THE HELICOIDAL CELL WALL AS A TIME REGISTER.

Helicoidal cell walls are characterized by an oscillatory shift in the arrangement of cellulose microfibrils somewhat reminiscent of the rotating movement of the hands of a clock. The periodic movement can be sustained or perturbed. Thus, the helicoidal cell wall presents a temporal reading. Sensitive to temporal signals, the cell wall keeps a record of cellular events and registers very small variations, storing data at a subcellular level. The present paper emphasizes some aspects of the helicoidal cell wall relevant to timekeeping, revealing its dynamics and flexibility and leading to the question of the mechanisms of its construction. Contents I. Summary 345 II. Introduction 345 III. Levels of timekeeping structures 346 IV. From watch to wall 347 V. Internal and external alterations 351 VI. Conclusions 353 References 354.