Figure 1.

Localization and histochemical staining of the differentiating endodermis and developing Casparian strips and suberin lamellae of sweet sorghum seminal roots. Freehand cross sections were made using 10-day-old seminal roots grown in nutrient solution. (a) Schematic view of endodermal differentiation. Stage I (0–10 mm from the root tip), without any Casparian strips or suberin lamellae; Stage II (20–25 mm from the root tip), with developing Casparian strips and suberin lamellae; Stage III (35–45 mm from the root tip), with developed Casparian strips and suberin lamellae. (b, d, f) Root cross sections stained with berberine aniline blue to show the Casparian bands, viewed under blue light (450 nm). Arrows indicate Casparian strips. (c, e, g) Root cross sections were stained with FY088 to show the suberin lamellae, viewed under UV illumination (365 nm). Arrows indicate suberin lamellae. mx, metaxylem; px, protoxylem; co, cortex; en, endodermis. Bar = 50 μm.