Effect of explant type and genotype on the accumulation of bioactive compounds in adventitious root cultures of Polygonum multiflorum

The correlation between growth and accumulation of bioactive compounds was investigated in six genotypes of Polygonum multiflorum , grown in vitro, soil-grown (ex vitro), and as adventitious root cultures. Adventitious roots were induced on leaf and root explants from plantlets of the six genotypes grown in vitro. Line PM-06 achieved the highest biomass in vitro (0.91 g plant −1 FW; 0.1 g plant −1 (DW)), whereas line PM-05 produced the highest biomass ex vitro (54.67 g plant −1 FW; 12.93 g plant −1 DW). A comparison of the six lines found that total phenolic content (TPC) and total flavonoid content (TFC) were highest in roots from line PM-01 grown in vitro, but line PM-06 produced the highest levels of bioactive compounds in tubers (99.06 mg g −1 DW TPC; 42.31 mg g −1 DW TFC), which were 2.5-fold, 5.0-fold, and 4.8-fold higher than the highest levels produced by in vitro roots, in vitro shoots, and ex vitro shoots, respectively. Although adventitious root line AR-06 produced the greatest overall biomass (60.12 g L −1 FW; 6.36 g L −1 DW), bioactive content was highest in line AR-01 (50.35 mg g −1 DW TPC; 22.51 mg g −1 TFC). There was a strong correlation between phenolic production in plant roots grown in vitro and adventitious root lines, and plant roots grown ex vitro and adventitious root lines. Adventitious root cultures of P. multiflorum line AR-06 showed great potential for producing phenolic compounds. Such cultures may therefore provide an alternative to naturally grown plants as a potential biomass source for the production of bioactive compounds.