The study documented for the first time the optimization of in vitro growing conditions for N. officinale microshoots. The experiments involved comprehensive optimization of culture conditions containing various PGR compositions, growth periods and types of in vitro cultures (agar, agitated). Moreover, the antioxidant potential of the studied biomass was evaluated. The experiments included both parent plant material and in vitro propagated microshoots. The research focused on testing the biomass response and incremental growth, and, moreover, the influence of various factors on the accumulation of secondary, biologically active metabolites such as glucosinolates and phenolic acids.
Significant effects of the PGRs, the growth period and type of culture were found on biomass increments in N. officinale in vitro cultures. Among the agar cultures, the highest Gi factor (Gi = 5.01) was obtained for the MS variant supplemented with 1 mg/L BA and 1 mg/L NAA after 30 days, and it was about 1.5 times higher than in the control sample (Table 1 and Table S2). By comparison, larger biomass increases were obtained for the agitated cultures. The highest biomass increment (Gi = 10.48) for this type of culture was recorded for the MS medium variant supplemented with 1 mg/L Zea and 1 mg/L NAA after a 20-day growth period (Table 1 and Table S2). In comparison with other microshoot cultures, the value of the Gi for the agar cultures was smaller than in Schisandra chinensis cv. Sadova agar cultures (max. 8.7, 60 days, MS medium containing 3 mg/L BA and 1 mg/L NAA). However, the N. officinale agitated in vitro cultures were characterized by greater increments in a shorter growth time. After a 20-day growth cycle, the increments were about 1.4 times greater than in S. chinensis cv. Sadova agitated cultures after a 60-day growth cycle [38].
The biotechnological experiments performed in our study proved the impact of in vitro culture conditions on the total amounts of glucosinolates. For the agar microshoot cultures, the highest content (194.77 mg/100 g DW) was obtained on the MS medium supplemented with 1 mg/L KIN and IAA after 30 days; it was 1.7 times higher than the highest content of the control set and 2.6 times lower than in the parent material (Figure 2, Table 5). In the agitated cultures, the total glucosinolate content was similar to that of the agar cultures. The highest total amount of glucosinolates (182.80 mg/100 g DW) in the agitated cultures was detected on the MS medium containing 1 mg/L BA and 1 mg/L NAA after 10 days of culture, and it was 2.7 times lower than in the parent plant (Figure 3, Table 5).
write only the main points
- The study optimized in vitro growing conditions for N. officinale microshoots for the first time
- Experiments involved optimization of culture conditions with various PGR compositions, growth periods, and types of in vitro cultures
- Antioxidant potential of the studied biomass was evaluated
- Significant effects of PGRs, growth period, and type of culture on biomass increments were found
- Agitated cultures showed higher biomass increments compared to agar cultures
- Total amounts of glucosinolates were influenced by in vitro culture conditions
- Highest content of glucosinolates in agar cultures was obtained on MS medium with 1 mg/L KIN and IAA after 30 days
- Highest total amount of glucosinolates in agitated cultures was on MS medium with 1 mg/L BA and 1 mg/L NAA after 10 days