Tabel 1 Root traits of plants grown in agar-filled Petri dishes measured non-destructively with the phenotyping system GrowScreen-Agar

Length primary root

Length of primary root (mm)

Length lateral roots

Length of lateral roots branched from primary root (mm)

Length total roots

Sum of primary and lateral root lengths (mm)

Number lateral roots

Number of lateral roots branched from primary roots

Lateral root density

Number of lateral roots per primary root length (mm⁻¹)

Branching angle

Angle between primary and branched lateral roots (°)

Diameter primary root

Average diameter of primary root (µm)

Diameter lateral roots

Average diameter of lateral roots (µm)

Root system depth

Maximum vertical depth of whole root system (mm)

Root system width

Maximum horizontal width of whole root system (mm)

Root area

Convex hull area, measured by encompassing a root system with the shortest line (mm²)

Root length density

Total root length per agar surface area (mm mm⁻²)

RGR primary root

Relative growth rate of primary root (% day⁻¹)

RGR lateral roots

Relative growth rate of lateral roots (% day⁻¹)

RGR total roots

Relative growth rate of whole root system (% day⁻¹)

Ratio lateral/primary root

Ratio between length of lateral roots and primary root

Ratio primary/rooting depth

Ratio between primary root length and root system depth