Influence of light conditions and nutrient medium composition on morphophysiological characteristics of in vitro plants of Carlina L. species

Aim. To investigate the effects of growth regulators on the development of in vitro plants of Carlina species (Carlina onopordifolia Besser ex Szafer, Kulcz. et Pawł, Carlina cirsioides Klokov, and Carlina acaulis L.) and functioning of their photosynthetic apparatus under different light conditions. Methods. Spectrophotometric methods, in vitro plant cultivation techniques, statistical methods, biometric measurements were used. Results. It was established that the use of MS/2 medium for plant cultivation proved optimal for leaf formation in C. onopordifolia and C. cirsioides. However, this medium was completely unsuitable for root system development, resulting in the rapid death of micropropagated plants. The chemical composition of the nutrient medium was adjusted for C. onopordifolia, C. acaulis, and C. cirsioides in accordance with the elemental composition of soils from their natural habitats. The effectiveness of the addition of the growth regulator IAA and the commercial product Trevitan® was shown to be species-specific. The optimal light intensity for each studied species under in vitro conditions was also determined. Conclusions. The results indicate that optimizing in vitro cultivation conditions for Carlina species requires consideration of the evolutionarily determined biological characteristics of each species.