Figure 1.

Turgor pressure of growing Lilium longiflorum (Lily) pollen tubes measured by pressure probe as described in [14]. (a) Time course of a representative experiment, showing very little change in turgor pressure during cell growth, until pressure was artificially increased and the cell burst, returning the probe to atmospheric pressure. Note that the tube wall withstood pressure over twice as large as that needed for growth before bursting. (b) In dozens of replicate experiments, growth rate was not correlated with turgor pressure. Even in the absence of growth cells maintained high turgor pressure. (c) Turgor pressure of lily pollen tubes in relation to impalement site of the pressure probe. Note the pressure values that were directly measured at the tube tip. Pollen grains were incubated in germination medium with various osmotica as indicated (unpublished data from [14]).