Morphogenetic, Physiological, and Biochemical Features of Lavandula angustifolia at Long-Term Micropropagation In Vitro

Data on morphogenesis and some physiological and biochemical parameters of explants of five cultivars of Lavandula angustifolia Mill. under long-term micropropagation in vitro during nine passages are represented. Introduction of meristems of the Stepnaya, Sineva, Vdala, Rannaya, and Record cultivars into the culture resulted in the formation of multiple shoots. Maximal number of shoots was observed in the Sineva cultivar (5.7), while minimal number was identified in the Rannaya cultivar (3.9). The experiments with micropropagation of lavender in nine subcultivations showed that the number of shoots increased in all cultivars up to the third subculture and decreased thereafter. The highest multiplication index (12.2) in this passage was observed for the Sineva cultivar. Further subculture were characterized by decrease of this parameter to 7.4–8.6. The lowest multiplication index in the fifth to ninth passages was observed for the Record cultivar (3.8–4.5). The analysis of the water regime of the microshoots obtained via in vitro multiplication showed that the total water content was 83–89%, while fractions of bound and colloid-consumed water made up to 40–57%. Record, Rannaya, and Vdala cultivars were shown to possess maximal water-retaining capacity. The obtained data indicate the active function of chlorenchyma. It was found that the Vdala and Sineva cultivars were characterized by maximal photosynthetic activity of their leaves and shoots and showed the highest viability index. The cultivars studied under the conditions of in vitro cultivation were characterized by a high level of proline, ascorbic acid, and phenolic compounds, especially flavanols. The highest level of proline was observed in the Vdala cultivar (372.87 µg/g), while the highest concentrations of ascorbic acid (31.28 mg/100 g) and phenolic compounds (1103 mg/100 g) were found in the Sineva and Rannaya cultivars, respectively. Shoots cultured in vitro were characterized by a high activity of catalase and low activity of superoxide dismutase and polyphenol oxidase. The highest catalase activity was observed in the Vdala and Sineva cultivars. The Sineva cultivar also demonstrated a high activity of polyphenol oxidase. The results obtained demonstrate the good ability of lavender to micropropagation in vitro, the efficiency of which depended on both the cultivar and the number of subcultures.