Pulses in turgor pressure and water potential : resolving the mechanics of hyphal growth

Hyphae do not grow at perfectly constant rates, but exhibit rapid oscillations in speed that are thought to reflect waves of vesicular fusion with the apical plasma membrane and dynamic changes in the mechanical properties of the cell wall. Theoretical considerations suggest that hyphal turgor pressure falls in response to wall loosening, and that the resulting differential between the water potential of the cell and its surroundings causes water influx. Measurements of micronewton forces exerted by single hyphal apices using a miniature strain gauge reveal the predicted fluctuations in turgor, and these show similar frequency to oscillations in the growth rate. This paper offers a conceptual framework for understanding the biomechanical processes that operate during hyphal growth.

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