Up Apical meristem Basal meristem Basal meristem Intercalary meristem Axillary meristem Axillary meristem Meristemoid Procambium Protoderm, promeristem Apical cell, fern Apical cell, Equisetum Mantle-Core Tunica-Corpus CMC zone Corpus zonation Cocklebur apex Large apex, cactus Large CMC. PRM Large PZ Files of cells Axillary bud, Coleus Axillary bud, ash Fern root tip Fern root, mag Cattail root tip Cattail apex, mag Cattail root cap Root protoderm Symplastic growth Corn root Corn root, mag
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Fig.
6.8-4a. Longitudinal section of a root apex in corn (Zea mays).
This longitudinal section shows many of the same features as occur in cattail (Typha)
in Fig. 6.8-2. Here too the root cap is distinct from the root, and the central
cylinder meristem is producing a broad set of cells that will develop into
vascular tissues. Notice how wide the entire root is,
even here near the apical meristem. You may be able to identify more than 50
rows of cells, so the mature root will be at least that many cells wide. That is
quite broad, and is much more typical of roots of monocots rather than dicots.
Dicot root apices tend to be much smaller. A higher magnification is shown in
Fig. 6.8-4b.
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