Root cell size and number analysis
Seeds of the sitl1 and WT were germinated and grown in
half-strength NS in a growth chamber under a 16-h photoperiod for 1
week. The detached roots were incubated in Propidium iodide (PI,
Sigma-Aldrich, USA) at a final concentration of 10 µM for 10 min.
Samples were rinsed three times with sterile deionized water to remove
unbounded PI, and mounted in 25% (v/v) glycerol on glass microscope
slides. Images of root meristem and root cells in the mature zone were
captured at 561 nm and 642 nm for excitation and emission, respectively,
via a confocal laser-scanning microscope (LSM 880, Carl Zeiss, Germany).
Cell length, width, and area of the root meristem zone and in the mature
root zone were determined using ImageJ software as described (Arnon,
1949; Lim et al., 2018).