80.0 MB (2.8 MB compressed)
5648 x 4949 pixels
47.8 x 41.9 cm ⏐ 18.8 x 16.5 in (300dpi)
DR KEITH WHEELER / SCIENCE PHOTO LIBRARY DR KEITH WHEELER / SCIENCE PHOTO LIBRARY
Dyer's greenweed stem. Polarised light micrograph of a transverse section through the stem of a dyer's greenweed (Genista tinctoria) plant. This stem has eight ribs with deep grooves with hairs, which reduce water loss through transpiration. Under the thick-walled epidermis (outer layer) with thick cuticle are layers of palisade-like cells (red-brown) containing chloroplasts (chlorenchyma) for photosynthesis. The vascular cylinder is made up of (from outside inwards) a ring of phloem sieve tubes (red black alternating patches), a ring of cambium (brown black), and xylem (blue white). In the centre of the stem is the pith made up of large celled parenchyma tissue (white-blue). Magnification: x103 when printed 10 centimetres wide.
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