atrichoblasts

Atrichoblasts are plant epidermal cells that do not develop into hair cells, or trichoblasts. In many dicotyledonous plants, epidermal patterning yields two fates: trichoblasts, which differentiate to form root hairs, and atrichoblasts, which remain hairless. The two cell types arise from the same epidermal lineage, and their fate is influenced by positional cues from underlying cortical cells as well as a regulatory network of transcription factors and signaling peptides.

Atrichoblasts contribute to the function of the root surface by forming a differentiated but non-hairy epidermis. Their presence contrasts with trichoblasts by lacking root hairs that increase surface area for water and nutrient uptake. The study of atrichoblasts, alongside trichoblasts, provides insight into plant patterning and epidermal cell differentiation. In model species such as Arabidopsis thaliana, researchers examine how cell fate is chosen and maintained in the root epidermis.

Identification is typically by microscopy and gene expression profiling, noting the absence of root hairs and the expression of specific marker genes associated with non-hair identity. While most discussions center on root epidermis, the term atrichoblast can also apply to hairless epidermal cells in other organs in some species.