The induction of beta vulgaris adventitious roots in in vitro culture and evaluation of their extracted betalains content

Abstract

Recently, betalains have gained the attention as natural food colorants because of their high anti-oxidative and free radical scavenging activities. This study focused on the process to induce the root formation from explants of Beta vulgaris L. - the main source of betalains by auxin supplementation and how to maximize the betalains amount produced in shake flask culture. IAA (1mg/L) was the best treatment to induce more roots from root explants, hypocotyl and cotyledon explants effectively rooted with NAA (0.5mg/L) and NAA (1mg/L) respectively. In shake culture, Beta vulgaris L. roots at 7g/L inoculum density reached peak of betalains (0.34mg/g FW) after 4-week cultivation at 7g/L inoculum; sucrose concentration at 20g/L and 30g/L show little significant difference in growth ratio as well as pigment biosynthesis. The addition of 1mg/L IAA remarkably increased growth of Beta vulgaris L. roots and the highest record of betalains yield was 0.53mg/g FW after 2-week cultivation. Keywords: Adventitious root, auxins, Beta vulgaris, betalains and food colorant.