Vein reticulation in seed ferns of the Dobrudzha coalfield Bulgaria

Alethopteris, Lonchopteris, Paripteris, Linopteris and Reticulopteris are abundant pteridosperm fronds in the Pennsylvanian-age Dobrudzha Coalfield. The transition from fan-shape to reticulate veining in Lonchopteris, Linopteris and Reticulopteris and in Laveineopteris to Reticulopteris is documented. The most probable cause for this is the decrease in humidity; in addition to temperature controls on the geographic distribution. The form and positioning of anastomoses are discussed.</p

Structure, habitat and seed of Mariopteris ZEILLER

The genus Mariopteris ZEILLER is distributed from the Namurian A to the early Stephanian in Europe. In the Dobrudzha Basin, numerous specimens are found mainly in flood plain claystones and siltstones. The habitat and reconstruction of the plants suggests a creeping manner of growth. Climatic changes are reflected in the architecture of species. One specimen has an attached seed proving the classification of the genus as a pteridosperm.</p

Ultracentrifuge methods for the analysis of polysaccharides, glycoconjugates, and lignins

Although like proteins, polysaccharides are synthesized by enzymes, unlike proteins there is no template. This means that they are polydisperse, do not generally have compact folded structures, and are often very large with greater nonideality behavior in solution. This chapter considers the relevant analytical ultracentrifuge methodology available for characterizing these and related carbohydrate-based systems and information this methodology supplies, in terms of sizes, shapes, and interactions using a comprehensive range of examples, including glycoconjugates and lignins. The relevance and potential of recent software developments such as SEDFIT-MSTAR, the Extended Fujita algorithm, and HYDFIT are considered

Vein reticulation in seed ferns of the Dobrudzha coalfield Bulgaria

Alethopteris, Lonchopteris, Paripteris, Linopteris and Reticulopteris are abundant pteridosperm fronds in the Pennsylvanian-age Dobrudzha Coalfield. The transition from fan-shape to reticulate veining in Lonchopteris, Linopteris and Reticulopteris and in Laveineopteris to Reticulopteris is documented. The most probable cause for this is the decrease in humidity; in addition to temperature controls on the geographic distribution. The form and positioning of anastomoses are discussed.</p