Direct shoot regeneration from nodes of Phalaenopsis orchids | Direktna regeneracija poganjkov iz nodijev orhidej Phalaenopsis

English. Nodes with dormant buds from flower stalks of orchid Phalaenopsis sp. were plated on six culture media. The composition of the culture media affected the induction, regeneration, number and form of Phalaenopsis regenerants. We managed to obtain direct shoot regeneration without callus formation on all media except for medium F. Medium A, supplemented with 2 mg/l of 6-benzylaminopurine (BAP) and 0.5 mg/l of a–naphtalenacetic acid (NAA) was found to be the most appropriate of all the media used for rapid micropropagation of a large number of vegetative shoots (multiplication factor 8.35 per node) without roots 160 days after inoculation. We found medium B, supplemented with 4.41 mg/l BAP and 1 mg/l NAA less appropriate for vegetative shoot production (multiplication factor 2.08 per node) also because the regenerants ceased to elongate. Medium C, containing BAP (2 mg/l) and a lower nitrogen content showed the highest multiplication rate (0.54 per node) for generative regenerants formation. Vegetative regenerants with a generative shoot also formed. This type of regenerant could be of major commercial interest, since period until flowering would be much shortened. Dormant bud induction was poor on medium E (23% regeneration rate) and there was no regeneration on medium F. Regenerants with well-developed roots on medium D (no hormones) most resembled the adult plants, but the vegetative multiplication rate was lower (1.18 per node). Most vegetative regenerants were ready for acclimatization after 90 days of subcultivation on medium D, which also proved to be a successful subcultivation medium for regenerants formed on media A, B and C.

Slovenian. Nodije z dormantnimi brsti s cvetnih poganjkov orhidej Phalaenopsis sp. smo inokulirali na šest različnih gojišč. Sestava gojišč je vplivala na indukcijo, regeneracijo in obliko regenerantov Phalaenopsis. Na vseh gojiščih z izjemo gojišča F je bila direktna regeneracija poganjkov brez oblikovanja kalusa. Ugotovili smo, da je gojišče A (2 mg/l BAP, 0,5 mg/l NAA) najprimernejše gojišče za hitro mikropropagacijo velikega števila vegetativnih poganjkov (multiplikacijski faktor 8,35 na nodij) brez korenin 160 dni po inokulaciji. Gojišče B (4,41 mg/l BAP, 1 mg/l NAA) je bilo manj primerno za nastanek vegetativnih regenerantov (multiplikacijski faktor 2,08 na nodij) tudi zaradi neizdolževanja regenerantov. Generativnih regenerantov je bilo največ (multiplikacijski faktor 0,54 na nodij) na gojišču C (2 mg/l BAP in nižja vsebnost dušika). Nastalo je tudi nekaj vegetativnih regenerantov z generativnim poganjkom, ki bi bili komercialno zelo zanimivi zaradi skrajšanega časovnega obdobja potrebnega do cvetenja. Indukcija dormantnih brstov je bila nizka na gojišču E (23% regeneracija) oziroma sploh ni bilo regeneracije na gojišču F. Regeneranti na gojišču D (brez hormonov) z dobro razvitimi koreninami so bili najbolj podobni odraslim rastlinam, vendar je bil multiplikacijski faktor za vegetativne poganjke nižji (1,18 na nodij). Večina vegetativnih regenerantov je bila primerna za aklimatizacijo že po 90-ih dneh subkultivacije na gojišču D. Gojišče D se je izkazalo tudi kot uspešno subkultivacijko gojišče regenerantov z gojišč A, B in C.