A user manual to measure gas diffusion kinetics in plants: Pneumatron construction, operation and data analysis

Abstract

The Pneumatron device presented measures gas diffusion kinetics in the xylem of plants. The device provides an easy, low‐cost, and powerful tool for research on plant water relations. Here, we describe in detail how to construct and operate this device to estimate xylem vulnerability to embolism, and how to analyse pneumatic data. Simple and more elaborated ways of constructing a Pneumatron are shown, either using wires, a breadboard, or a printed circuit board. The instrument is based on an open-source hardware and software system, which allows users to operate it in an automated or semi-automated way. A step-by-step manual and a troubleshooting section are provided. An excel spreadsheet and an R-script are also presented for fast and easy data analysis. This manual should help new users to avoid common mistakes, especially regarding stable measurements of the minimum and maximum amount of gas that can be discharged from xylem tissue.

Reconciling discrepancies in measurements of vulnerability to xylem embolism with the pneumatic method

“…The Pneumatron may also allow the pneumatic method to be applied more generally, including to gymnosperms, which previously had given problematic results (it is for this reason we focussed only on angiosperm species within the cited studies) (Sergent et al, 2020;Pereira et al, 2021). For detailed practical advice on the construction and use of the Pneumatron (including open-source software for study, modification and distribution by anyone), and guidance on best practices for implementing high-quality pneumatic measurements generally, we refer readers to Trabi et al (2021).…”

Dynamic changes in gas solubility of xylem sap reiterate the enigma of plant water transport under negative pressure

“…A lateral branch was cut and connected to a Pneumatron device (Pereira et al ., 2020a; Trabi et al ., 2021) for gas discharge measurements (Fig. 1).…”

A crucial phase in plants – it's a gas, gas, gas!

“…These instruments were initially designed to take manual discharge measurements of gas created by embolism in conduits of dehydrating xylem tissue (Pereira et al ., 2016; Bittencourt et al ., 2018). By making measuring steps fast and automated, Pneumatrons have been shown to provide a fast and easy approach to directly measuring embolism resistance in xylem (Pereira et al ., 2020a; Trabi et al ., 2021). A first important point that was discussed in detail by Roman Link (University of Würzburg, Germany) highlighted the need for a robust metrological framework for comparing mismatches between methods, including pneumatic, hydraulic, visual, or acoustic quantification of embolism.…”