Ex vitro morphological and anatomical features of lavender and lavandin microplants

O.V. Mitrofanova, V.A. Brailko, I.V. Zhdanova, A.I. Borkuta, M.S. Andreev, I.V. Mitrofanova
Lavender is used as an essential oil, medicinal, aromatic and ornamental plant. In the Crimea, cultivars of lavender and lavandin are in great demand. To improve the plant material, obtain the highest multiplication rate and preserve valuable genotypes, their explants were introduced to in vitro culture. Growth and adaptive capacity of the obtained in vitro plantlets were studied in vivo. The rooted plants were transferred to a mixture substrate. The plants were cultured in the greenhouse for 5 months. Observations of the growth processes were performed every 10 days. Samples for structural studies of vegetative organs were collected ex vitro (on the 14th day) and in vivo – after 60 and 150 days from rooting. Intensive growth in vivo was noted from the 20th to 60th day. The height of the plants was 9-24 cm (maximum – ‘Belyanka’ and ‘Rabat’). After 150 days during in vivo adaptation, the leaf blades were of the same size and shape as those ex situ, with typical features of the cultivar. The leaf thickness was 250-274 μm, the leaves were bifacial, hypostomatic, with differentiated 5-7-layered mesophyll and multiple simple and glandular trichomes (52-90 trichomes mm‑2). Stomata functioning became optimal after 60 days (in cultivar ‘Belyanka’ after 20-30 days). Palisade index was 0.56-0.64. Essential oil drops were noted in epidermal cells, trichomes, leaf mesophyll and parenchyma bundle sheath cells. In the plants of cultivars ‘Belyanka’, ‘Rabat’ and ‘Snezhnyi Bars’ flowering shoots were formed after 120-140 days under in vivo culture. Thus, the presented study revealed lavender and lavandin plants ability to form vegetative and generative organs under in vivo conditions that were structurally and functionally identical to those ex situ. Adaptation capacity depended on the genotype and growing conditions.
Mitrofanova, O.V., Brailko, V.A., Zhdanova, I.V., Borkuta, A.I., Andreev, M.S. and Mitrofanova, I.V. (2020). Ex vitro morphological and anatomical features of lavender and lavandin microplants. Acta Hortic. 1285, 23-30
DOI: 10.17660/ActaHortic.2020.1285.4
Lavandula angustifolia, Lavandula × intermedia, in vitro plantlets, ex vitro and in vivo adaptation, morphology, structure

Acta Horticulturae