A root penetration model of Arabidopsis thaliana in phytagel medium with different strength

Abstract

Phytagel media were evaluated as systems to mechanically impede roots of A. thaliana. Studying mechanical properties of Phytagel and exploring the root response to mechanical stimulation can facilitate plant culture and plant development. Breaking strengths of 0.5-2.0% phytagel media were tested by uniaxial compression test. Different phytagel concentrations were set to alter the strength of layers in growth medium. Negative correlations were observed between root length, straightness and medium strength. When roots elongated through soft upper-layer (0.6%), penetration ratio decreased with the increase of lower-layer strength (0.6-1.2%) and all roots couldn't penetrate into lower-layer with concentration ≥1.2%. Roots could grow into soft lower-layer (0.6%) from hard upper-layer (0.6-1.2%), with decreased penetration ratio. When roots grew in soft lower-layer, the growth rate linked with upper-layer strength increased to peak. Roots penetration capability into 1.2% lower-layer was improved by growing plants through moderate layer inserted between soft and hard layer, and roots in 0.8% moderate medium have a significant higher penetration ratio than that in 1.0%. It was concluded that the Phytagel systems studied were suitable for studying the effect of mechanical impedance on the elongation of A. thaliana roots. The medium strength affected root penetration significantly and acclimation can improve root penetration capability.

Root growth responses to mechanical impedance are regulated by a network of ROS, ethylene and auxin signalling in Arabidopsis

“…Root bending has also been observed in roots grown in a medium consisting of a soft upper layer and a hard lower layer. The root exhibits a bending response at the lower, harder layer (Yamamoto et al, 2008;Yan et al, 2017Yan et al, , 2018. It has been suggested that a zone of 'mechanical weakness' is required for the bending process and that this is localised between the growing and mature zones of the root (Bizet et al, 2016).…”

Coevolution of both Thermostability and Activity of Polyphosphate Glucokinase from Thermobifida fusca YX

“…Different from typical solid agar-based media, highly thermostable Phytagel, which can remain solid for 1 h at 120°C, was used for screening in directed evolution. To the best of our knowledge, Phytagel was normally used for the cultivation and isolation of hyperthermophilic bacteria (43) or plant tissue (44). Herein, we adopted it for the application of Phytagel-based plates as a thermotolerant gelling agent to replace the use of agar plates at enzyme engineering for enhanced thermostability by directed evolution.…”

Trait-Based Root Phenotyping as a Necessary Tool for Crop Selection and Improvement

“…Agar-based phenotyping does have some drawbacks. Agar must be prepared to a resistance similar to that of soil so that roots can penetrate and adequate structural support is provided for the plant [84]. Agar, while a solid, does not have pore space like soil, which may influence root growth.…”

“…Agar, while a solid, does not have pore space like soil, which may influence root growth. Seeds inserted fully into agar can become sealed and lack enough gas exchange to promote germination [84]. Varying methods of planting have been utilized for gel-based systems to combat these problems.…”