The majority of plant species (including most ferns and dicots, as well as many monocots) exhibit Type I root hair development, in which every root epidermal cell can potentially differentiate into a root hair (Figure 18.35A). (...) In Type II plants, which include the primitive vascular plants Lycopodium, Selaginella and Equisetum, the basal angiosperm family Nymphaeceae (water lilies), and some monocots, root hairs arise from the smaller cell produced by an asymmetric cell division in the root meristem (Figure 18.35B). (...) In Arabidopsis, for example, the root epidermis consists of alternating files of cells that are either atrichoblasts or trichoblasts (Figure 18.35C). (...) Each root hair cells has a long, fingerlike extension that usually grows from the basal end of the epidermal cell (see Figure 18.35).
"Plant Physiology and Development" int'l 6e - Taiz, L., Zeiger, E., Møller, I.M., Murphy, A.
