Root Morphology and Development of Bell Peppers

Abstract

Abstract Bell peppers (Capsicum annuum L. ‘Early California Wonder’ and ‘Yolo Wonder’) were grown for 14 and 22 days in glass tubes with agar supplemented with 87.6 mm (30 g·liter–1) sucrose or without sucrose, respectively, under controlled conditions. Taproot length increased rapidly for 6 days after radicle protrusion, but its growth rate was reduced during the next 4 days for both cultivars in each medium. Basal and lateral roots emerged 5 and 6 days after germination, respectively, or just after cotyledons were expanded fully for both cultivars in either medium. However, ‘Early California Wonder’ produced basal and lateral roots 9 days after germination in agar medium without sucrose. The number of lateral roots did not increase between 6 and 10 days after radicle protrusion in agar medium without sucrose. However, emergence of lateral roots was pronounced during this period in agar amended with sucrose. Root morphological characteristics, shoot weight, shoot:root ratio, and stem height differed minimally between ‘Early California Wonder’ and ‘Yolo Wonder’. The sequence of root development in bell pepper seedlings was characterized by a) rapid taproot elongation from radicle protrusion to fully expanded cotyledons, b) emergence of basal roots followed by lateral roots when cotyledons were fully expanded, and c) increase in the number of basal and lateral roots numbers particularly in the presence of sucrose and reduction in the rate of taproot elongation. Exogenous sucrose reduced the variability for most measured shoot and root characteristics.