A taxonomic revision of Iris subser. Sibiricae is provided based on morphological and molecular analyses and the study of protologues and original material. Two to three species have been recognized in this subseries by botanists. To address the question of species delimitations and relationships within this group, we analyzed four non-coding regions of plastid DNA (trnS–trnG, trnL–trnF, rps4–trnSGGA, and psbA–trnH) for samples from 26 localities across the distribution ranges of two currently recognized species, I. sanguinea and I. sibirica. Variance analysis, based on nine characters, revealed no separation between taxa. Moreover, no morphological character could be used to define clear boundaries between taxa. Our results strongly support that I. subser. Sibiricae is monotypic and comprises only I. sibirica, instead of two or three species. Iris sibirica is morphologically variable and one of the most widespread Eurasian species of Iridaceae. Previously accepted taxa, I. sanguinea and I. typhifolia, are synonymised with I. sibirica and also two names, I. orientalis and I. sibirica var. haematophylla, which are typified here, are placed in the synonymy of I. sibirica. Information on the distribution of I. sibirica and the main features used to distinguish between I. sibirica and I. subser. Chrysographes species are provided.

We tested the differentiation and morphogenetic capacity of floral organs of Iris ensata, I. setosa , and I. sanguinea cultured in vitro . Organogenesis through direct formation of shoots from explants, callogenesis, and floral organogenesis were demonstrated in I. ensata callus culture in vitro . These processes depended on the plant species and on the content of phytohormones in the medium. Adventitious shoots proved to develop on the basal part of the perianth tube and on the apical part of the ovary, while roots were not formed. Direct organogenesis was induced by the following phytohormones: α -naphthylacetic acid and 6-benzylaminopurine for I. ensata and 2,4-dichlorophenoxyacetic acid and 6-benzylaminopurine for I. setosa and I. sanguinea ; while callogenesis was induced by 2,4-dichlorophenoxyacetic acid. The obtained data indicate that development of adventitious structures from iris floral organs requires the presence of 6-benzylaminopurine in the growth medium. PLANT PHYSIOLOGYŠ š

Megadenia Maxim. is a small genus of the Brassicaceae endemic to East Asia with three disjunct areas of distribution: the eastern edge of the Qinghai-Tibetan Plateau, the Eastern Sayan Mountains in southern Siberia, and Chandalaz Ridge in the southern Sikhote-Alin Mountains. Although distinct species (M. pygmaea Maxim., M. bardunovii Popov, and M. speluncarum Vorob., Vorosch. and Gorovoj) have been described from each area, they have lately been reduced to synonymy with M. pygmaea due to high morphological similarity. Here, we present the first molecular study of Megadenia. Using the sequences of 11 noncoding regions from the cytoplasmic (chloroplast and mitochondrial) and nuclear genomes, we assessed divergence within the genus and explored the relationships between Megadenia and Biscutella L. Although M. bardunovii, M. speluncarum, and M. pygmaea were found to be indiscernible with regard to the nuclear and mitochondrial markers studied, our data on the plastid genome revealed their distinctness and a clear subdivision of the genus into three lineages matching the three described species. All of the phylogenetic analyses of the chloroplast DNA sequences provide strong support for the inclusion of Megadenia and Biscutella in the tribe Biscutelleae. A dating analysis shows that the genus Megadenia is of Miocene origin and diversification within the genus, which has led to the three extant lineages, most likely occurred during the Early-Middle Pleistocene, in agreement with the vicariance pattern. Given the present-day distribution, differences in habitat preferences and in some anatomical traits, and lack of a direct genealogical relationship, M. pygmaea, M. bardunovii, and M. speluncarum should be treated as distinct species or at least subspecies.

Flavonoids uncharacteristic of intact plants were isolated from callus tissue of Iris ensata and were identified as 5-hydroxy-4′-methoxyflavone, 5-hydroxy-3′-methoxyflavone, and 5-hydroxy-2′-methoxyflavone using PMR and mass spectrometry. It was proposed that the lack of growth of callus tissue after changing cultivation conditions was related to the inhibiting effect of these flavones on cell proliferation.Key words: Iris ensata, Iridaceae, callus tissue, 5-hydroxy-4′-methoxyflavone, 5-hydroxy-3′-methoxyflavone, 5-hydroxy-2′-methoxyflavone.Flavonoids are the most studied group of secondary plant metabolites from the Iridaceae family [1]. Information on the contents of these compounds is used in chemotaxonomic studies of representatives of this family. The flavonoid composition is known for almost 60% of Iris species [2]. However, little attention has been paid to the secondary metabolites of in vitro tissue from cultivated species of this genus. It has been demonstrated that Iris cell cultures contain terpenoids [3,4]. Earlier we studied the qualitative pigment composition of I. ensata Thunb. heterotrophic callus culture [5]. A determination of the nature of pigments from callus tissue of this plant indicated an acculumation of flavonoids. The goal of the present work was to isolate and identify red pigments from callus tissue of I. ensata.Extract of I. ensata callus tissue contained three isomers of 5-hydroxy-monomethoxyflavone. The isolated compounds were identified as 5-hydroxy-2-(4-methoxyphenyl)-chromen-4-one (5-hydroxy-4′-methoxyflavone) (1), 5-hydroxy-2-(3-methoxyphenyl)-chromen-4-one (5-hydroxy-3′-methoxyflavone) (2), and 5-hydroxy-2-(2-methoxyphenyl)-chromen-4-one (5-hydroxy-2′-methoxyflavone) (3).Compound 3 and other lipophilic flavones unsubstituted at the 7-position were observed in secretory emissions of aerial organs of plants from the genus Primula [6,7]. It has been found that flavones found in leaves of P. veris are synthesized in in vitro cultivated tissues of this plant [8].The results suggest that the spectrum of synthesized secondary-exchange compounds changed in callus culture of I. ensata when compared with the intact plants. According to the literature, intact plants of this species contain flavonoid pigments of the anthocyan [9, 10], flavone, and xanthone [11] types. However, the dominant pigments in callus tissue were lipophilic flavones 1-3 uncharacteristic of this plant.Our results for the pigment composition of I. ensata callus tissue showed that flavone formation in tissue was suppressed in the subcultivation medium [5]. However, the change of cultivation conditions (reduced content of phytohormones, increased concentration of saccharose, change of pH) favored flavonoid accumulation and inhibited callus growth.It was noted that the synthesis of secondary compounds in isolated instances was related to a slowing or cessation of cell proliferation [12,13]. Apparently the flavonoids identified by us and compounds similar to them in biogenetic origin were responsible for the suppression ...

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