Effect of light intensity on in vitro regeneration in some relict endemic species of the Crimean flora
One of the least studied aspects of the Crimean flora relict endemics propagation and preservation in vitro is the effect of physical factors (light intensity and spectrum, photoperiod) on the regeneration rate. In the presented studies the influence of white or red light with the intensity 37.5, 56.0 and 74.0 µmol m‑2 s‑1 with 16-h photoperiod and white light (45.25 µmol m‑2 s‑1) with 14-h photoperiod at the constant temperature (22°C) on regeneration capacity of shoot nodal segments in Lamium glaberrimum, Scrophularia exilis, Heracleum ligusticifolium, Silene jailensis, and microrosettes in Crepis callicephala and Crepis vesicaria subsp. bivonana were studied. Positive effect of the white light on the microshoot regeneration in L. glaberrimum, Scr. exilis, C. callicephala, C. vesicaria subsp. bivonana, and S. jailensis was revealed at 37.5 µmol m‑2 s‑1 and 16 h photoperiod. However, in L. glaberrimum microshoot length, number of leaves and internodes were significantly higher in comparison with other species. Under the same physical factors in the species Scr. exilis the number of microshoots per explant was significantly higher (18 ones). An increase in the white light intensity up to 56.0-74.0 µmol m‑2 s‑1 caused leaf chlorosis in L. glabeirrimum, Scr. exilis, and hydration in S. jailensis. At 56.0-74.0 µmol m‑2 s‑1 light intensity an increase in the number of adventitious rosettes shoots and hydrated leaves in C. callicephala and C. vesicaria subsp. bivonana was induced. The red light with an intensity 37.5-74.0 µmol m‑2 s‑1 caused leaf and microshoot hydration in L. glaberrimum and Scr. exilis. Active formation of adventitious rosettes in two Crepis species under the red light, 37.5 µmol m‑2 s‑1 intensity, was noted. Leaf yellowing and hydration were observed at 56.0-74.0 µmol m‑2 s‑1. For H. ligusticifolium regeneration frequency was increased 2-2.5 times under the red light intensity 37.5 µmol m‑2 s‑1 and 16 h photoperiod. The hydrated shoots and leaves formation was observed under the light intensity 56.0-74.0 µmol m‑2 s‑1. This is the first report on the developmental biology in six relict endemic species of the Mountain Crimea flora in vitro. Our results demonstrated that the physical factors (light intensity and spectrum, photoperiod) had a significant effect on the morphogenetic capacity realization in vitro.
Mitrofanova, O.V., Ivanova, N.N., Lesnikova-Sedoshenko, N.P., Brailko, V.A., Zhdanova, I.V. and Mitrofanova, I.V. (2021). Effect of light intensity on in vitro regeneration in some relict endemic species of the Crimean flora. Acta Hortic. 1324, 27-34
rare species, regeneration capacity, light intensity, light spectrum, photoperiod, in vitro