Roots - 4 Primary Root Structure (Mature region of roots) Epidermis • Single layer of cells with very little cuticle or suberin • Root hairs are found in the region of early maturation in the epidermis. The extension of the cell greatly increases surface area for absorption of water and nutrients. In one study (as reported in the Raven text) a rye plant had 14 billion root hairs with an absorption surface area of 401 square meters. As the epidermal cells mature, the root hairs atrophy, and are replaced by newer cells with root hairs in the early stages of maturation. Root hairs Root cap mucigel • The active absorption region of roots is coated by the mucigel that provides an environment favorable to mineral and water uptake and may protect the root from dehydration. There is some evidence that nitrogen-fixing bacteria are attracted to the mucigel, as well. The mucigel-soil area around the root tip is called the rhizosphere. Cortex
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