Measurement of Cytoplasmic Streaming in Chara Corallina by Magnetic Resonance Velocimetry

TL;DR

This study uses magnetic resonance velocimetry to measure cytoplasmic streaming in Chara corallina, confirming theoretical models of fluid flow driven by cytoplasmic forces transmitted through the tonoplast.

Contribution

First whole-cell velocity measurements of cytoplasmic streaming in Chara corallina, validating a recent theoretical model of shear transmission and flow dynamics.

Findings

Velocity field measurements match theoretical predictions

Shear transmission occurs efficiently through the tonoplast

Cytoplasmic streaming driven by bidirectional helical forces

Abstract

In aquatic plants such as the Characean algae, the force generation that drives cyclosis is localized within the cytoplasm, yet produces fluid flows throughout the vacuole. For this to occur the tonoplast must transmit hydrodynamic shear efficiently. Here, using magnetic resonance velocimetry, we present the first whole-cell measurements of the cross-sectional longitudinal velocity field in Chara corallina and show that it is in quantitative agreement with a recent theoretical analysis of rotational cytoplasmic streaming driven by bidirectional helical forcing in the cytoplasm, with direct shear transmission by the tonoplast.