Fig. 6: Arabidopsis ESBL is essential for CS development and salt tolerance under high transpiring condition.

a Confocal z-projections of endodermal Casparian strip autofluorescence. b The intensities and pattern of the CS autofluorescence in the indicated genotypes. The measurements were conducted at the locations indicated by the yellow lines in (a). a.u., arbitrary units. c–e Fluorescence assay of endodermal suberin deposition using fluorol yellow 088 staining. The results showed the locations where the endodermal suberin deposition start (c), the pattern (d) and intensities (e) of fluorescence in the indicated samples. f–g PI penetration-based assay of the function of endodermal CS barrier. ep, epidermis; co, cortex, en, endodermis. Quantification in (c) and (g) was done by counting endodermal cells after the onset of elongation as described in previous study², and the results were expressed as mean ± SD of 8 roots. The images in (a, d and f) were respectively taken at ~25^th, ~40^th and ~25^th endodermal cell after the onset of elongation, and the images were representative of three independent repeats with similar results. h–j The appearances (h), SPAD values (i) and shoot Na⁺ contents (j) of esbl-1, esbl-2, esb1 and wild-type plants with the indicated treatments. Plants were grown in standard conditions for 4 weeks, and then watered once to soil saturation with either 150 mM NaCl or water (Control). Seven days later, the plants were photographed, the SPAD values of the 4^th leaf were measured, and the shoot Na⁺ contents were determined. The results in (i) and (j) were means ± s.d. of three independent experiments. Bars in (a, d and f), 20 μm; Bars in (h), 1 cm. Source data are provided as a Source Data file.