Xenbase Image ID: 176690

FIGURE 3. Structure of stem apex (A), young leaf (B), leaflet blade (C–G), leaf petiole (H,I), and leaf sheath (J–L). Stegmata in leaves are associated with both fiber bands and vascular sclerenchyma. (A) Stereomicroscope image of the shoot apex showing the shoot apical meristem (sam), leaf primordia (lp), vascular bundles (vb), and fiber bands (white arrowheads). (B) Unstained paradermal section of a young leaf from a date palm seedling showing epidermal cells, stoma (st), and subepidermally occurring stegmata (red arrowheads) attached to the surface of a fiber band. (C–G) Adult leaflet from a 10-year old. Unstained sections (C,E) show epidermal and hypodermal layers at the leaf surface, mesophyll with vascular bundles (vb), and fiber bands (white arrowheads) occurring both adaxially and abaxially. In the central part of the leaflet the mid vein is absent (E) and expanding tissue of large parenchyma cells is present adaxially (exp). In the opposite-abaxial part, two large fiber bands are developed. Stegmata adjacent to the fiber bands and sclerenchyma sheaths of vascular bundles can be seen in high magnification (D) and more clearly in longitudinal sections (F,G). Alcian blue/safranin stained samples (D,F,G). (H,I) Leaf petiole and (J–L) leaf sheaths of adult 10-year-old plant in unstained cross-sections are shown either under white light (H,J,L) or UV irradiation (I). (J,K) Phloroglucinol-HCl staining visualizing cell wall lignification. Leaf petiole and leaf sheath are covered by a single layer epidermis and lignified hypodermis (I,J). Mesophyll is composed of chlorenchyma (H,I) and parenchymatous ground tissue. Peripherally present fiber bands (white arrowheads) and large sclerenchyma sheaths of vascular bundles are accompanied by stegmata, as seen in high magnification (F,G,K,L). The ground tissue cells usually contain a number of starch grains (sg). Larger Image Printer Friendly View

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