Figure 4.

Pico gauge pressure measurement in sieve element and fungal cells. A to D, Four frames extracted from Supplemental Movie S5. A, A pico gauge tip is located in front of a sieve element with a sieve plate (angled arrow) and a forisome in the low-volume state (dashed arrow), indicating uninjured conditions. The oil/water interface in the pico gauge is marked by the solid arrow. B, Impalement of the pico gauge into the sieve element leads to an instant compression of the oil, which provides the pressure reading. C and D, The forisome switches into the high-volume state within 1 s, but the measurement is already completed before the forisome blocks the tube. E and F, Two frames extracted from Supplemental Movie S6 showing a pico gauge measurement in a fungal hyphae cell with a volume of only about 900 fL. The compression of the pico gauge fluid is minor (23 fL) but sufficient for a pressure calculation. The oil/water interface is shown by the arrows. Bars = 25 μm.