TABLE 1.

List of the measured anatomical traits acquired with ImageJ on the root cross‐section images that have been used to get the GRANAR parameters

Measured anatomical traits on the root cross‐section image		GRANAR parameters
Traits	Description from traits to parameter	Tissue type	Properties	Unit
EpW	Epidermis cell radial width	epidermis	cell_diameter	μm
ExW	Exodermis cell radial width	exodermis	cell_diameter	μm
nCF	Number of cortex cell layer	cortex	n_layers	#
CoW	Cortex width (CoW) divided the number of cortex cell layer (CF)	cortex	cell_diameter	μm
EnW	Endodermis cell radial width	endodermis	cell_diameter	μm
PeW	Pericycle cell radial width	pericycle	cell_diameter	μm
SD	Global stele diameter	stele	layer_diameter	μm
nS SW	The number of stele cells on the stele diameter (nS) is used to divide the global stele diameter (SD) in order to obtain the stele cell radial width (SW)	stele	cell_diameter	μm
MXA MXW	The Metaxylem vessel area (MXA) is used to calculate the metaxylem vessel diameter (MXW) based on circular assumption	xylem	max_size	μm
nMX	Number of Metaxylem vessels	xylem	n_files	#
nPX	Number of Protoxylem vessels (nPX) divided by the number of Metaxylem vessels (nMX)	xylem	ratio	#