Fig. 3.

An oxygen-permeable window site in the adventitious roots of Echinochloa colona. Cross-section of an adventitious root showing the location of a window (white arrow) at a site in the exodermis where a lateral root is expected to emerge. The window is composed of passage cells that lack suberin lamellae. Suberin lamellae are indicated as yellow-green fluorescence with Fluorol Yellow 088 (yellow arrowhead). Red arrowhead indicates the pericycle from which lateral root primordia are predicted to emerge. Blue fluorescence indicates autofluorescence. Fluorol Yellow 088 staining was conducted as described in Ejiri and Shiono (2019). The plants were grown in an aerated nutrient solution for ten days and then transferred into a deoxygenated stagnant nutrient solution for 14 days. Abbreviations: CP, cortical parenchyma; end, endodermis; epi, epidermis; exo, exodermis; LP, lateral root primordia; scl, sclerenchyma; ste, stele. Scale bars: 100 μm.