Mericarp (nutlet) micromorphology and pericarp structure of three morphologically similar endemic Salvia species; Salvia hedgeana, S. huberi and S. rosifolia were investigated using LM, SEM and TEM. Salvia hedgeana has larger mericarps and abscission scars than S. huberi and S. rosifolia. Mericarp length to width ratio ranges from 1.11 in S. hedgeana to 1.60 in S. huberi. Mericarp shape is mainly ovoid, rarely broadly ovoid in S. hedgeana, and oblong in S. huberi. The mericarp surface sculpturing pattern in all species is colliculate. However, exocarp cells are pentangular-hexangular in S. hedgeana, irregular in S. huberi and rounded and smaller in S. rosifolia. In Salvia huberi anticlinal walls are undulate whereas in S. hedgeana and S. rosifolia anticlinal walls are straight. Salvia hedgeana was distinguished from the others by the thickest pericarp (146-185 µm). The sclerenchymatous region significantly varied between the species. It was 84-99 µm in S. hedgeana, 56-82 µm in S. huberi and 27-61 µm in S. rosifolia. The mesocarp was also thicker in S. hedgeana. The wetted mericarps produced mucilage, but S. huberi differed from the others in having translucent-milky white opaque mucilage with fibres or radiating cordons.

Seed morphology and histology of 12 taxa (nine species, two subspecies, one variety) of Paronychia Miller (Caryophyllaceae) by light and scanning electron microscopes revealed that seeds are laterally compressed, reniform, and hilums are linear. Testa surface structures are alveolate-scalariform, colliculate, reticulate-alveolate, rugose and ruminate. Differences in cuticle and papillae properties of epidermal cells have been observed. A dichotomous key has been developed for Paronychia agryloba Stapf, P. angorensis Chaudri, P. arabica (L.) DC. subsp. euphratica Chaudri, P. carica Chaudri, P. cataonica Chaudri, P. condensata Chaudri, P. davisii Chaudri, P. dudleyi Chaudri, P. galatica Chaudri, P. kurdica Boiss subsp. kurdica var. kurdica, P. kurdica Boiss subsp. montis-munzur Chaudri and P. mughlaei Chaudri.   Key words: Paronychia; Caryophyllaceae; Seed morphology; Seed histology; Turkey DOI: 10.3329/bjb.v38i2.5142 Bangladesh J. Bot. 38(2): 171-176, 2009 (December)

Marrubium genus is represented by 19 taxa in Flora of Turkey (19 species, 3 subspecies). 11 out of 22 taxa are endemic for Turkey and rate of endemism is 52%. Anatomical, histological and cytological features of the leaf, stem and root in Marrubium bourgaei and M. heterodon taxa of genus Marrubium L. from Lamiaceae family were studied and taxonomic significances were identified. The leaves were amphistomatic and hypostomatic. Stomata were amaryllis type and anomocytic as indicated by neighbouring cells. The leaves of the examined Marrubium species were bifacial (dorsiventral) and a high number of prismatic crystals were observed in the leaf mesophyll tissue. The stems were angular and stomata were observed in local areas of epidermis. The underneath of stem epidermis were a few layers of collenchyma cells. In leaf cross sections, protective tissue was comprised of periderm and a nucleus at the center consisting of tracheids.

Seed coat development in the natural tetraploid Trifolium pratense L. was studied by electron microscopy. The mature seed coat derived from the outer integument is composed of three layers of cells. The cells of the outer epidermis divide anticlinally and undergo radial elongation to form a macrosclereid layer. The cells are characterized by thin walls, the presence of amyloplasts, and numerous vacuoles which are completely or incompletely filled with tannin. The outer tangential walls are thickened at an early stage. An electron‐translucent cap develops in the outer tangential walls of the macrosclereid cells at the globular embryo stage. Osteosclereid cells are highly vacuolate with densely staining cytoplasm. Gradually, extensive intercellular spaces are formed. The parenchyma cells are small and have prominent intercellular air spaces. Maturation eventually leads to the disappearance of cytoplasm in all cells, and the compression of the cells of the parenchyma layer.

Previous reports of plant regeneration of natural tetraploid T. pratense L. 'Elçi' could be realized only through the apical meristem calli. In order to proceed to the production stage, other regeneration methods need to be tried. Aseptic seedlings were used for the production of somatic embryos through various 2,4-D and kinetin trials. Nonuniform external callus cells with translucent cytoplasm were observed in various developmental stages of somatic embryos. Beneath these cells, there were uniformly aligned, darkstained embryo cells with dense cytoplasm. Despite the similar developmental stages and cell characteristics of zygotic and somatic embryos, the walls of somatic embryo cells revealed a highly wavy pattern. The nucleus generally contained only one nucleolus, which was spherical, dark stained, and electron-dense. Electron-dense droplets were seen in vacuoles. The cytoplasm consisted of starchcontaining amyloplasts, mitochondria, plastids, ribosomes, endoplasmic reticulum, dictyosomes, lipid, and protein bodies. In some of the somatic embryos at the globular and heart stages, vacuole or electron-translucent zones were observed in the nucleolus. Additionally, a few embryo degenerations were recorded during developmental stages of the zygotic embryo. For the first time, the somatic embryos of natural tetraploid T. pratense were produced from hypocotyl (85%), cotyledon (75%), and apical meristem (60%) explants in 0.3 mg/L 2,4-D and 2 mg/L kinetin-containing MS medium. Our study developed an effective and efficient in vitro production method for using natural tetraploid T. pratense in biotechnological studies.