Abstract
Radish sprouts were incubated in water or PK-S (ALA containing liquid fertilizer) solution in the dark for 8 days and then in the light for 2 days at 25℃. Levulinic acid (LA), a competitive inhibitor in ALA dimerization-reaction at different concentrations was added to water or PK-S solution at 2, 12, 24, or 48 hours before the harvest. After the incubation endogenous ALA concentration in the plants was determined using HPLC. ALA concentration was 16μg/100g-FW when the plants were incubated in water. But it increased to 411, and 906μg/100g-FW respectively when 25mL LA was added to water, or PK-S solution at 48 hours before the harvest. These were the maximum concentrations in the experiments of LA alone and the combinations of LA and PK-S. And it was suggested that ALA and NO3- in PK-S contributed to the increase of endogenous ALA concentration.
