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Regeneracija in vitro gajenog biljnog tkiva kontrolisana je regulatorima rastenja, naročito citokininima i auksinima. Egzogeno primenjeni biljni regulatori rastenja mogu interagovati sa endogenim biljnim hormonima i uticati na njihovu biosintezu ili distribuciju, odnosno menjati hormonalnu homeostazu koja utiče na razviće in vitro. Proces regeneracije biljaka in vitro podrazumeva intenzivne ćelijske deobe, a centralnu ulogu u kontroli ćelijskog ciklusa i razvića organa imaju kompleksi ciklina i kinaza zavisnih od ciklina na čiju sintezu, odnosno aktivnost, utiču pomenuti biljni hormoni. U tom smislu, ciljevi ovog rada bili su uspostavljanje efikasnih protokola za regeneraciju biljaka kelerabe (Brassica oleracea L. var. gongylodes) in vitro, sa posebnim osvrtom na identifikaciju i kvantifikaciju različitih grupa citokinina i indol-3-sirćetne kiseline (IAA) u eksplantatskim tkivima sa regenerisanim izdancima, kao i analiziranje obrazaca i intenziteta ekspresije gena koji kodiraju cikline i kinaze zavisne od ciklina tokom de novo organogeneze izdanaka. Efikasan sistem za repetitivnu somatsku embriogenezu (SE) kod kelerabe, sorta Bečka Plava (BP), je uspostavljen iz nezrelih zigotskih embriona. Najveća frekvencija SE detektovana je kod nezrelih zigotskih embriona u ranom kotiledonarnom stadijumu razvića gajenih na hranljivoj podlozi bez regulatora rastenja. Uspešna indukcija de novo organogeneze izdanaka kelerabe, sorte BP i Bečka Bela (BB), postignuta je kod odsečaka hipokotila i intaktnih klijanaca, na podlogama sa pojedinačnim citokininima (CK): 6-benzilaminopurin (BAP), tidiazuron (TDZ), transzeatin (transZ) ili cis-zeatin (cisZ). Frekvencija regeneracije kao i vijabilnost regenerisanih izdanaka obe sorte je bila veća kod intaktnih klijanaca, dok su među primenjenim citokininima BAP i TDZ bili najefikasniji u indukciji de novo organogeneze. Kvantifikacija endogenog sadržaja citokinina i IAA u odsečcima hipokotila sa regenerisanim izdancima (HRI) kao i u intaktnim klijancima sa regenerisanim izdancima (KRI) je ukazala na to da uočene razlike u organogenom odgovoru ova dva tipa početnog biljnog materijala mogu biti povezane sa njihovim hormonskim statusom... vitro plant regeneration is under control of plant growth regulators (PGRs), especially cytokinins and auxins. Exogenously applied PGRs can affect the homeostasis of endogenous plant hormones by influencing their biosynthesis and distribution, subsequently altering in vitro development. Intensive cell divisions represent the basis of in vitro plant regeneration, and they are controlled by complexes of cyclins and cyclin-dependent kinases. The activity of these complexes during cell cycle and organ development is affected by plant hormones. Respecting this, the aims of this study were developing efficient protocols for in vitro regeneration of kohlrabi (Brassica oleracea L. var. gongylodes) with an emphasis on identification and quantification of different groups of endogenous cytokinins and indole-3-acetic acid (IAA) in explant tissue with respective regenerated shoots, as well as analyzing expression of genes encoding cyclins and and cyclin-dependent kinases during de novo shoot organogenesis. Efficient system for repetitive somatic embryogenesis (SE) was developed for kohlrabi cv. Vienna Purple (VP) using immature zygotic embryos. The highest frequency of SE was obtained from immature zygotic embryos at the early cotyledonary stage grown on PGR-free medium. Successful induction of de novo shoot organogenesis in kohlrabi cv VP and cv. Vienna White (VW) was achived using hypocotyl explants and intact seedlings, cultivated on media supplemented with single cytokinin (CK): 6-benzylaminopurine (BAP), thidiazuron (TDZ), trans-zeatin (transZ) or cis-zeatin (cisZ). Higher frequency of shoot regeneration as well as viability of regenerated shoots was detected for intact seedlings, with BAP and TDZ being the most efficient in de novo organogenesis induction. Quantification of endogenous cytokinin and IAA contents in both hypocotyl explants and seedlings with regenerated shoots (HRSs and SRSs, respectively) suggested that the observed differences in organogenic response between these two types of starting plant material were related to their cytokinin and IAA contents. The level of total CKs was higher in HRSs, while SRSs displayed a higher IAA/bioactive CKs ratio...