To obtain healthy and good quality plants from in vitro cultivation, it is necessary to produce plantlets with well-developed rooting systems because they must undergo acclimatization, a final and a very difficult stage of micropropagation. In the present research, the effect of auxins NAA, IAA and IBA in concentrations of 0.5; 1; 2.5 and 5 mg·dm−3 on the Paphiopediluminsigne in vitro rooting was studied, and it was noted that 1 mg·dm−3 of IAA or IBA enabled the obtaining of a lot of rooted and good quality plantlets. The subsequent influence of the two most advantageous auxins on the acclimatization of plantlets in different substrates (sphagnum moss, sphagnum moss + substrate for orchids, substrate for orchids, substrate for orchids + acid peat) was tested, in the means of morphological features of plants and their physiological parameters, i.e., chlorophyll fluorescence (FV, Fm, Fv/Fm), stress enzyme activity (catalase, ascorbate peroxidase), and water balance. Considering all the tested features, it might be stated that the best results were obtained when explants were rooted in vitro in the presence of 1 mg·dm−3 of IAA and then planted ex vitro in substrate for orchids.

Initiation of tissue culture of many plant species is a very difficult stage due to appearance of many contaminations. The other problem might be a choice of media for regeneration. Initiation of grass species tissue cultures are thought to be very difficult. Therefore, a research was undertaken to evaluate the use of nano-silver particles for plant material disinfection and to estimate a medium Pennisetum alopecuroides. The plant material were buds and nodal explants that were disinfected in 2% NaOCl for 30 min or 0.1% HgCl2 for 1 min. Half of the explants disinfected with NaOCl were soaked in 50, 100 or 250 mg·dm Ag–3 NPs for 1 hour. Explants not soaked in nano-silver were placed on media with Ag NPs at concentrations of 4, 8 or 16 mg·dm–3. An influence of growth regulators on Pennisetum alopecuroides was evaluated in vitro. Regenerated shoots were placed on MS media with: 3 mg·dm–3 BA + 0.3 mg·dm–3 IBA, 3 mg·dm–3 KIN + 0.3 mg·dm–3 IAA, 1 mg·dm–3 BA + 0.1 mg·dm–3 IBA. It was observed that the use of nano-silver particles lowered the level of contamination. The best results were obtained when Ag NPs was used at concentration of 100–250 mg·dm–3 alone or as a supplementation of the media, at concentration of 4 mg·dm–3 for nodes and 16 mg·dm–3 for adventitious buds. The use of nodal explants allowed to obtain less contamination. Regeneration depended on a media content. The most regenerated shoots were obtained on the MS media supplemented with 1 mg·dm–3 BA and 0.1 mg·dm–3 IBA.

Paphiopedilum is a very original orchid, which labellum resembles a slipper. It is cultivated as a cut flower or a pot plant. The aim of the presented work was to estimate the influence of a disinfection method and addition of a liquid media on germination of Paphiopedilum insigne seeds in vitro. The whole seed capsules were disinfected with the use of 0.5% of AgNO3 for 20 min, 0.1% of HgCl2 for 5 s, 1% NaOCl for 30 min or immersed in a 96% ethanol and burned in a direct flame. The disinfected seeds were placed on a 1/4 MS (Murashige and Skoog) solidified media on top of which a liquid phase containing 1/4 MS elements, GA3 in concentration of 400 mg·dm–3 or distilled sterile water were added. The media without the liquid phase was also tested. It was noted that all methods of disinfection used effectively reduced contaminations of Paphiopedilum insigne seeds. The highest germination rate was observed when capsules were direct flamed and the liquid phase was added on top of the solidified media. The influence of growth regulators (BA, TDZ, KIN and 2,4-D) and casein hydrolysate added to the media on the morphological features of the obtained plants was also tested. It was observed that the most regenerated protocorms of the best quality were obtained when the media was supplemented with 1 mg·dm–3 of BA + 2 mg·dm–3 of TDZ or 5 mg·dm–3 of KIN + 1 mg·dm–3 of BA.

The aim of work was to evaluate the influence of cytokinins on dahlia propagated in vitro and their consequent effect on acclimatization. Plant material were shoot tips and nodes. From three cytokinins, benzyladenine, kinetin and 2-isopentenyl-adenine, only BA effectively stimulated shoot multiplication from axiliary buds. The highest multiplication rate was obtained from nodes in presence of 0.25–0.5 mg·dm–3 BA. Higher concentrations shortened internodes and decreased leaf blades and growth of callus. 1 mg·dm–3 of KIN and 2iP positively influenced shoots growth and size of leaves. Gibberellic acid (GA3) used with BA increased the number of axillary shoots. The best quality shoots and the highest multiplication rate were obtained when 2 mg·dm–3 BA was used with 5 mg·dm–3 GA3. Cytokinins affected rooting and acclimatization ex vitro. Dahlias shoots multiplicated in presence of 1 mg·dm–3 KIN or 2iP rooted faster in the soil and 100% survived in field, while those from 1 mg·dm–3 BA media rooted slowly, had shorter shoots and only 60% survived. Plants bloomed after 11–12 weeks in the field. Dahlia plants that had been multiplicated in presence of KIN had a bigger diameter and fresh weight in the field. BA and 2iP positively influenced flowers diameter, length of flower stalk and a number of first order shoots.

No abstract

Characteristics of plants of the genus

Phenolic compounds limit micropropagation of many orchids in vitro. The aim of the study was to estimate the effect of activated charcoal (AC);1, 2 or 4 g/L) or ascorbic acid (AA; 10, 20 or 30 mg/L) added to the half strength MS medium on the growth and o-dihydroxyphenols content in Paphiopedilum insigne in vitro. A positive effect of AC on the shoot and root formation has been found. The highest multiplication rate (5.6 shoots/explant) and rooting frequency were obtained on medium containing 2 g/L of AC. However, AC reduced the leaf number as compared to the control. The lowest content of o-dihydroxyphenols was marked in Paphiopedilum insigne leaves when the shoots were grown on medium with 10 mg/L AA, followed by AC at 1 or 2 g/L.

Paphiopedilum is an ornamental orchid used mainly for interior decoration. As the division of plants is uneconomical, a fast method of propagation is needed. The aim of this study was to evaluate the influence of medium type (MS or VW), growth regulators, i.e. BA, KIN, TDZ used separately or in combinations and natural additives, i.e. coconut water, banana pulp, casein hydrolysate, on Paphiopedilum insigne plantlets grown in vitro. It was found out that BA in concentration of 0.5 mg·dm–3 allowed to obtain the highest multiplication rate (2.92), however the use of KIN in concentration of 1 mg·dm–3 resulted in formation of bigger and higher quality plantlets, It is possible to replace cytokinins with other biologically active substance, such as banana pulp. The 1/2 MS medium might be used for Paphiopedilum insigne tissue culture, as there was no difference in terms of multiplication rate and the obtained plantlets were of better quality, especially that it is cheaper and easier to prepare.