Figure 5

Staining for suberin and lignin in the outer cell layers of rice roots grown under aerated or stagnant deoxygenated conditions. Nine-day-old rice plants were grown in aerated nutrient solution (Aerated conditions; a, c) or stagnant deoxygenated agar solution (Stagnant conditions; b, d) for 14 days. Basal parts (10-20 mm regions from the root-shoot junction) of the adventitious roots were sliced into 80-μm-thick sections, and were incubated in lactic acid saturated with chloral hydrate at 70°C for 1 h for clearing. For suberin staining, sections were stained with Fluorol Yellow 088 at room temperature for 1 h and observed under UV-light with epifluorescence microscopy (a, b). For lignin staining, sections were stained for 5 min with phloroglucinol/hydrochloride at room temperature to visualize lignin with cinnamyl aldehyde groups (c, d). White arrow indicates yellow-green fluorescence of suberin at hypodermis/exodermis and black arrow indicates orange-red pigmentation of stained lignin at the sclerenchyma. Ep, epidermis; Ex, exodermis; Sc, sclerenchyma; Co, cortex. Scale bars = 50 μm.