Figure 4

Confocal imaging of wall ingrowth deposition in PP TCs in cotyledons, cauline leaves and sepal. A. Minor vein from the base of an 18 day-old cotyledon showing extensive wall ingrowth deposition (arrows) in PP TCs (asterisks). B. Minor vein from the mid-region of an 18 day-old cotyledon showing highly sculptured and extensive wall ingrowth deposition (arrows) in PP TCs (asterisks). C. Minor vein from the tip an 18 day-old cotyledon showing massive levels of wall ingrowth deposition (arrows) that occupy a considerable volume of each PP TC (asterisks). The fragments of fluorescent labelling seen in bundle sheath cells in both B and C correspond to remnant starch grains not completely extracted by the bleach treatment. D. Wall ingrowth deposition (arrows) in PP TCs (asterisks) in a fully expanded cauline leaf. E. Wall ingrowths in a minor vein of sepal, showing numerous localized patches of wall deposition (arrows) along each PP TC (asterisk). F. Wall ingrowths in a minor vein of sepal showing apparent consolidation or merging of localized patches of wall ingrowth material (arrows) in a PP TC (asterisk). BS, bundle sheath cell; CC, companion cell; XE, xylem element. Scale bars = 10 μm in A, B and C. Scale bars = 5 μm in D, E and F.