Bell peppers (Capsicum annuum L. `Early California Wonder') were seeded in glass tubes on agar-based media adjusted to pH 4.1, 5.9, or 7.3 to evaluate germination, emergence, shoot growth, and root morphology for 16-day-old seedlings. Taproot lengths were measured daily from 1 to 10 days following radicle protrusion. Time from seeding to germination (radicle protrusion) differed by only one-half day among pH treatments. Peppers in a pH 5.9 medium emerged (fully expanded cotyledons) 1 day earlier than plants grown in media at pH 4.1 or 7.3. Plants grown in a pH 5.9 medium had higher shoot and root weights and longer stems than plants grown at pH 4.1 or 7.3. Shoot: root ratios were similar regardless of medium pH. However, taproot growth rate from 1 to 10 days after radicle protrusion was faster for plants grown in a pH 5.9 than in a pH 4.1 or 7.3 medium. On average, there was one basal and one lateral root per plant and they were minimally influenced by pH. The data suggest that acidic or alkaline media adversely affect early shoot and taproot development of bell peppers, but with minimal influence on time to germination or emergence, and on subsequent lateral and basal root initiation.
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