The role of plant growth regulators in enhancing bulking of dicer carrots (Daucus carota var sativus)

In Nova Scotia, cool springs, low summer irradiance, cool falls and early frosts have all combined to slow the bulking process of dicer carrots, limiting their potential to achieve yield and grade targets. PGRs are proposed as a means of altering the histological development of the storage root to increase root sink strength.;It was hypothesized that encouraging the induction of the vascular cambium through the use of ethylene protagonists would increase root size at harvest and throughout the life of the plant.;It was also hypothesized that polyamines would enhance root bulking by encouraging early induction of the vascular cambium and encouraging an increased rate of cell division from the cambium.;In a field trial in 2001, spermidine was used in combination with or without ethephon.;Under controlled conditions, young (12–24 days) untreated carrots and those treated with spermidine at 0.1 ppm and ethephon at 10 ppm were examined for endogenous ethylene production and histological development.;The results were discussed in relation to potential triggers of bulking and the relationship of polyamines to ethylene. (Abstract shortened by UMI.).