Root sections of cranberry (Vaccinium macrocarpon Ait. cv. Searles) were microscopically examined to document the typical anatomy of cranberry roots and changes in root anatomy in response to N-form and solution pH. Cranberry cuttings were rooted, then established in hydroponic conditions with three N and two pH regimes. The three N regimes with equal N levels were 1) NH4-N alone, 2) NH4/NO3-N in combination, or 3) NO3-N alone. pH was maintained at 4.5 or 6.5. Root apical regions were examined using phase contrast, bright field, and epifluorescence microscopy. The cranberry root tip develops with a closed apical organization with the tetrarchal vascular cylinder, cortex, and root cap traceable to independent meristem cell layers. The most obvious treatment difference was an accumulation of unidentified “granules” in the subepidermal layer, readily visible with epifluorescence microscopy with NO3-N alone. Roots produced at pH 4.5 branched less than those at 6.5 and had more “quiescent” root initials; at pH 6.5, these developed more frequently into branch roots.
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