Sugar and Β-Carotene Accumulation in Carrot (Daucuscarota L.) Tap Roots As Influenced By Fertilization and Bio-Stimulant Application under Greenhouse Conditions (Published)

Article Author: Sekoli M.M.S., Pretorius J.C and Coetzer G.M

Greenhouse study was carried out to evaluate β-carotene and sugar accumulation in carrot tap roots, at harvest, after treatment with different fertilizer levels either separately or in combination with two commercial bio-stimulants, ComCat® and Kelpak®. Four fertilizer levels included standard recommended NPK level (100%) as well as 50%, 25% and 0% of standard. Foliar application of bio-stimulants was according to recommendations by the manufacturers. Treatments were replicated five times in complete randomized block design. Translocation of sugar was followed by labelling leaves with U-14C-glucose. Both β-carotene and sucrose content increased more or less linearly with increasing fertilization, but most significant increase was observed when carrots were treated with combination of ComCat® at 50% of standard fertilizer rate. In the case of sucrose this was in concert with a significant increase in the translocation of radio-activity from the leaves to the roots where ComCat® was applied in combination with higher fertilizer regimes. Glucose and fructose levels fluctuated rather inconsistently. Kelpak® had no effect on β-carotene content and had inhibitory effect on sucrose content.