Abstract:

The effects of exogenous 5-aminolevulinic acid on the growth and quality of carrot under tape for direct sowing were studied in order to provide a theoretical basis for the application of 5-aminolevulinic acid on carrot. ‘Kuroda 5 Inch Ginseng’ carrot was used as the test material, and tape for direct sowing of carrot was adopted. Different concentrations (0, 10, 25, 50, 100 mg/L) of 5-aminolevulinic acid (ALA) solution were sprayed to the leaves. After harvest, the yield and quality of carrot were evaluated by measuring the root length, root diameter, root weight, leaf length, and the content of chlorophyll, soluble protein, soluble solids and carotene. The results indicated that 10-50 mg/L ALA could increase the plant height and chlorophyll content of carrot leaves, and the root weight, root length, root diameter and dry matter content increased by 73.05%, 15.56%, 18.75% and 25.31%, respectively, compared with those of control (without ALA application). In addition, relatively low concentration of ALA increased the content of soluble solids, soluble protein and carotene in the fleshy taproot of carrot, while relatively high concentration of ALA inhibited the growth of carrot and reduced the quality of the fleshy taproot. 50 mg/L ALA had the best performance in promoting the growth and quality of carrot, and the study could provide reference for carrot production practice.

Key words: 5-Aminolevulinic acid, carrot, growth, quality, yield, tape for direct sowing