The Pneumatron estimates xylem embolism resistance in angiosperms based on gas diffusion kinetics: a mini-review
Understanding hydraulic failure of angiosperm xylem and its underlying mechanisms are relevant to reveal how plants respond to climate change, especially during severe drought events. Various methods to quantify embolism resistance have been developed over the last decades, including hydraulic (e.g., bench dehydration and centrifuge methods), and non-hydraulic approaches (e.g., the optical method and microCT). However, there is a need to develop a low-cost and relatively fast method that can be applied easily by plant scientists to hundreds of samples. Pneumatic measurements offer a highly promising approach to fulfil these requirements. The Pneumatron measures the kinetics of pressure change under partial vacuum while extracting gas from a cut open xylem tissue. The method is based on Fick's law for diffusion, Henry's law for partitioning of gas concentration between liquid and gas phases at equilibrium, and the ideal gas law. Our pneumatic measurements demonstrate that the molar air discharge shows a striking similarity to embolism resistance of xylem based on traditional methods. A major advantage of the Pneumatron is that potential artifacts associated with hydraulic measurements are avoided, while high accuracy is obtained with the automated design of the device. It can be applied to various organs (stem, roots, leaves), and will be useful to study the mechanisms behind air-seeding.
Jansen, S., Guan, X., Kaack, L., Trabi, C., Miranda, M.T., Ribeiro, R.V. and Pereira, L. (2020). The Pneumatron estimates xylem embolism resistance in angiosperms based on gas diffusion kinetics: a mini-review. Acta Hortic. 1300, 193-200
xylem embolism, pneumatic method, vulnerability curves, drought resistance, plant hydraulics