Try it on paper first. A hint, the key idea and the worked solution are here when you need them.
Ravi cuts a thin slice across a young stem and labels six parts on his drawing: the epidermis, a trichome, the cortex, the pith, the phloem and the cambium. (a) Put each of the six parts under the right tissue system. (b) Which of the three systems is made of two different complex tissues?
Epidermal tissue system: epidermis with cuticle (cutin, absent in roots), stomata (bean-shaped guard cells in dicots, dumb-bell in grasses; thick inner wall, thin outer wall; subsidiary cells; the stomatal apparatus), root hairs (unicellular) and trichomes (multicellular, on stems). Ground tissue system: all but epidermis and vascular bundles; cortex, pericycle, medullary rays, pith; mesophyll in leaves. Vascular tissue system: xylem and phloem; open bundles (cambium, dicot stem) and closed (monocot stem); conjoint (stems, leaves) and radial (roots); collateral and bicollateral; endarch xylem in stems, exarch in roots.
Have you tried it?
Work it out on paper first. It is fine to get stuck or make a mistake: that is how we learn. When you are ready, go through the solution one step at a time, and check each step against your own.
Step 1. The epidermal system. The epidermis and the trichome. A trichome is an outgrowth of the epidermis.
Step 2. The ground system. The cortex and the pith. They fill the body of the stem.
Step 3. The vascular system. The phloem and the cambium. They belong to the vascular bundle.
Step 4. Two complex tissues. The vascular system is made of xylem and phloem.
Answer: (a) epidermal: epidermis, trichome; ground: cortex, pith; vascular: phloem, cambium; (b) the vascular tissue system.
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