Structural features of vegetative organs in some Ficus carica L. cultivars cultured in vitro

Common fig (Ficus carica L., Moraceae) is still an important subtropical fruit in many countries. The objective of our study was to investigate some aspects of vegetative organs’ morphology and anatomy of in vitro plantlets in fig cultivars, used for dried fruit production. The samples were collected after 5 months and 4 years of in vitro micropropogation. The culture was carried out on MS medium with 1.5 mg L^‑1 BAP, 0.2 mg L^‑1 NAA and 0.25 mg L^‑1 GA₃ at 24±1°C, 16-h photoperiod and light intensity 37.5 μmol m^‑2 s^‑1. Microshoots of 1.3-2.3 cm height were formed. Five-month cultured microshoots were characterized by 3-9 leaves formed per explant in cultivars ‘Datte de Naples’ and ‘Nikitskiy Suhofruktovyiy’̍. Cultivar ‘Desertnyiy’̍ during this period was able to form 3-5 shoots with small leaves (18-20 shoot^‑1). Long-term culture of the studied cultivars was favourable for active adventitious shoot formation. Leaf blades were green and of typical fig shape. The values of photosynthetic activity of fig leaves of investigated cultivars were indicated between 0.54-0.71 a.u. (“arbitrary units”), which demonstrated the normal functioning of the assimilation apparatus. The total water content of regenerants was 83-88%. Leaf blades were 79-110 μm thick, bifacial, hypostomatic. Mesophyll was differentiated. Cover tissues consisted of a single-layer epidermis with a thin cuticle layer, with multiple simple and glandular trichomes (33-90 μm long). Stomatal apparatus were of anomocyte type. The analysis of structural features of microshoots allows us to evaluate the studied cultivars as highly adaptive, promising for plant conservation and in vitro culture.