All chemicals used to treat SOK-YFP roots are shown in Extended Table 1 . Concentration for each chemical was obtained from literature. Seedlings were placed on MS plates containing each chemicals for the durations mentioned in the text and were subsequently imaged by confocal microscopy. As controls for the chemical treatments, the same percentage of DMSO or ethanol used for each chemical treatment were used and no effect was observed. For most of the chemical treatments, final concentrations of DMSO were <0.5% (v/v) and ethanol were <0.1% (v/v).
Plasmolysis was performed either on MS medium with mannitol (Sigma, M9546) at final concentration 0.4 M or by dipping roots in 0.4 M mannitol solution in milliQ water, and stained by FM4-64 at least for 2 min. For cell wall digestion, either 1% Cellulose R10 (Yakult Honsha Co. L.T.D, Japan) and/or 0.2% Macerozyme (Duchefa) were used. Cellulose and/or Macerozyme was dissolved in a solution containing 0.4 M mannitol, 10mM CaCl2, 20 mM KCl and 20 mM MES (pH 5.7).
Plasmolysis was performed either on MS medium with mannitol (Sigma, M9546) at final concentration 0.4 M or by dipping roots in 0.4 M mannitol solution in milliQ water, and stained by FM4-64 at least for 2 min. For cell wall digestion, either 1% Cellulose R10 (Yakult Honsha Co. L.T.D, Japan) and/or 0.2% Macerozyme (Duchefa) were used. Cellulose and/or Macerozyme was dissolved in a solution containing 0.4 M mannitol, 10mM CaCl2, 20 mM KCl and 20 mM MES (pH 5.7).