Adaptation to Ex Vitro Conditions of Microplants Lavandula Angustifolia Mill. At Long-Term Reproduction in Vitro

Abstract

The purpose of the study is to identify the features of adaptation to ex vitro conditions of lavender plants after long-term clonal micropropagation. The experiments were carried out on microplants of narrow-leaved lavender (Lavandula angustifolia Mill.), cv. The number of plants in each subcultivation - n=10 pcs., 3-fold repetition. Microplants with well-developed shoots and roots were planted in a mixture of peat and perlite (1:1) and grown at illumination of 2–3 klx, photoperiod duration of 16 h, temperature of 24 ± 2°C, air humidity of 70%. The frequency of adaptation of microplants, depending on the number of subcultivations, varied slightly and amounted to 83...100%. On the 60th day of adaptation, the length of the shoot was significantly higher by 21...28% in microplants after 8 subcultivations (206.73 mm) compared with 14, 15 and 16 passages. There were no differences in the length of additional shoots depending on the amount of subculturing. According to the number of nodes on the main shoot, a tendency to their decrease with an increase in the number of passages was observed. A significant increase in the content of chlorophyll a with an increase in the number of subcultivations on the 14th day of adaptation was revealed, however, later these differences leveled out. On average, the in vitro viability index for passages was 1.45 and increased up to 30 days of adaptation to 1.75. The revealed features of changes in morphometric and physiological parameters indicate a good adaptive ability of the analyzed plants, while micropropagation in vitro during 16 subcultivations did not significantly reduce their adaptive potential. The optimal period of ex vitro adaptation is the period of 45...60 days, during which the plants formed well-developed shoots (3.20...6.00 g) and root system (0.619...1.143 g).