Three-dimensional in vivo analysis of water uptake and translocation in maize roots by fast neutron tomography

Abstract

Root water uptake is an essential process for terrestrial plants that strongly affects the spatiotemporal distribution of water in vegetated soil. Fast neutron tomography is a recently established non-invasive imaging technique capable to capture the 3D architecture of root systems in situ and even allows for tracking of three-dimensional water flow in soil and roots. We present an in vivo analysis of local water uptake and transport by roots of soil-grown maize plants—for the first time measured in a three-dimensional time-resolved manner. Using deuterated water as tracer in infiltration experiments, we visualized soil imbibition, local root uptake, and tracked the transport of deuterated water throughout the fibrous root system for a day and night situation. This revealed significant differences in water transport between different root types. The primary root was the preferred water transport path in the 13-days-old plants while seminal roots of comparable size and length contributed little to plant water supply. The results underline the unique potential of fast neutron tomography to provide time-resolved 3D in vivo information on the water uptake and transport dynamics of plant root systems, thus contributing to a better understanding of the complex interactions of plant, soil and water.

Quantification of root water uptake and redistribution using neutron imaging: a review and future directions

“…Note that the volume of the soil column in Tötzke et al. (2021) was 3.8% of the rhizobox in Ahmed et al. (2016b).…”

“…Using this technology, Tötzke et al. (2021) observed non‐uniform water uptake in the root system of 2‐week‐old maize. The water was mainly taken up by the primary root (Figure 3b), in contrast to the observations of Ahmed et al.…”

“…Overview of the main neutron tomography studies on root water uptake in lupine and maize. (a, b) Time series of water movement and distribution after D 2 O injection at the bottom of the soil column for lupine (after Tötzke et al., 2017) and maize (after Tötzke et al., 2021), respectively. Images in (a) show the formation and ascent of the H 2 O front within 6 min after D 2 O injection.…”

Particle-Based Imaging Tools Revealing Water Flows in Maize Nodal Vascular Plexus

“…Imaging-based plant physiology study approaches provide an effective tool for many current and challenging tasks that require the precise quantification of objects based on the analysis of their various features. Tools for imaging water flows inside plant tissues are diverse, for example, recent advances in the Raman imaging of water-transporting xylem vessels [9] or the fast neutron tomography of root water uptake [10]. Among them, X-ray micro computed tomography (micro-CT) allows three-dimensional visualization to be obtained, revealing the spatial configuration and distribution of vascular bundles.…”

Neutron computed laminography yields 3D root system architecture and complements investigations of spatiotemporal rhizosphere patterns

“…In-situ imaging methods have been applied to study the root system of soil-grown plants. 3D non-invasive methods such as neutron tomography (Moradi et al 2011;Tötzke et al 2017Tötzke et al , 2021, X-ray tomography (Aravena et al 2011;Koebernick et al 2017) or magnetic resonance tomography (Pohlmeier et al 2008;van Dusschoten et al 2016) can yield detailed information on root system architecture and rhizosphere behavior. The maximum diameter of the usually cylindrical plant containers ranges from 30-120 mm depending on the imaging modality as well as the desired spatial resolution.…”