In this elaboration, effective methods of in vitro propagation of a Paulownia tomentosa × Paulownia fortunei hybrid are presented, and the variable costs of commercial production evaluated. Plant regeneration of the P. tomentosa × P. fortunei hybrid was achieved through organogenesis in nodal explants. Different concentrations of BAP (6-benzylaminopurine), 0.2, 0.5, 1 mg/L, and light conditions were investigated. The best results were obtained using a half-strength MS medium containing 0.5 mg/L BAP. In standard light conditions, 2 shoots were grown with 3.5 culturable nodes on each, and in 70% reduced light, 2 new shoots were grown with 6 culturable nodes on each. Rooting was successfully achieved when using a hormone-free half-strength MS medium containing vitamin, and 2% sucrose with 95% efficiency. Acclimatization and survival were shown to be 90% in regenerated plants. The cost of production of a single plant of P. tomentosa × P.fortunei hybrid grown in standard light conditions was $0.084 and $0.082 when grown in 70% reduced light where only variable costs were considered. Two major factors affecting P. tomentosa × P fortunei hybrid micropropagation is labor, materials and chemicals. Focusing on reducing this cost can highly lower plantlet price.

The aim of the study was to compare the variable costs of planting material production using the example of vitro cultures of Pennisetum × advena ‘Rubrum’. In the study, temporary immersion system (TIS)- and agar-based methods were used in innovative workday organisation. The workday structure involved a six-hour passaging period followed by a two-hour break for medium preparation, autoclaving, and maintenance tasks. The TIS was found to be more cost-effective than the agar cultures, with lower labour costs and comparable growing expenses. The most expensive element of agar production was labour which was 43% of the costs. The second biggest cost was materials and reagents which represented 25%. In a TIS, production materials and reagents are the most expensive part of production (44%), while labour represents 24% of costs. A TIS offers a much faster multiplication of plants than agar cultures. Plants obtained in the multiplication phase are two times cheaper using a TIS. Rooting accounted for a significant portion of production costs in both methods. Overall, the TIS demonstrated superior efficiency and cost-effectiveness compared to agar cultures in producing Pennisetum × advena ‘Rubrum’ plants.

The aim of this study was to propose an efficient method of Pennisetum x advena ‘Rubrum’ micropropagation. Agar cultures with MS medium supplemented with BAP in various concentrations (0.5 mg/L-2 mg/L) and a temporary immersion bioreactor system (TIS) with liquid medium MS with an addition of 1 mg/L BAP were used. For rooting ½ MS medium with different auxin combinations (IBA, NAA) and activated charcoal was utilized. The most efficient method turned out to be TIS which produced 36.9 new plants in four weeks. The seedlings were slender in shape, bright green in colour with no signs of hyperhydricity. The most suitable agar medium produced 19.5 new plants in an eight week period. Rooting should be carried on ½ MS supplemented with 0.5 mg/L IBA and 0.5 mg/L NAA with an 84% rooting rate. The addition of activated charcoal inhibited rooting.