Morphological and physiological features in some Ficus carica L. cultivars in vitro

Abstract

Ficus carica L. plants in vitro culture have a great interest due to the high nutritional value of their fruits, obtaing plants resistans to viral diseases, the large-scale production of improved plant material and preservation of the unique fig gene pool collected in Nikita Botanical Gardens. The aim of our studies was to identify structural and metabolic features in vegetative organs of two fig cultivars (Pomoriyskiy and Sabrutsiya Rozovaya) under various durations of in vitro culture. WPM medium supplemented with 0.7-2.0 mg/L BAP, 0.15-0.5 mg/L NAA and 9 g/L agar (pH 5.8-5.9) was used for morphogenesis induction. Microshoots were cultured for 100 and 390 days (they were subcultured every 20-25 days) at 24±1°C, 16-h photoperiod and light intensity 37.5 μmol m^-2s^-1. Morphometric measurements were made in 30 replications; histological analysis was performed on temporary microscope slides. Some aspects of water content in microshoot tissues and their assimilation activity were studied. Plants regenerated in vitro had morphologically and functionally normal microshoots and actively photosynthesized leaf blades. Leaves were bifacial, hypostomatic, thin and xeromorphic. Chlorenchyma was differentiated. Mesophyll was better developed under morphogenesis initiation after 100-days culture. Epidermis was covered with thin cuticle. Simple trichomes and multiple stomatal apparatus of anomocyte type were noted. Cover tissues demonstrated better defined features needed for water stress adaptation under prolonged culture ex vitro . The total water content in tissues was high, water fractions repartition to increasing the part of bound water occurred after 390-days culture. Presented data gave us possibility to optimize the time of fig plants in vitro culture stages as well as they can be used for advanced breeding and identification of the criteria for abiotic stressors resistance in fig plants according to the cultivation zone.