30. Gerhard Follmann: Zur Bedeutung der Salzbestäubung für den Wasserhaushalt von Küstenflechten

Nach gravimetrischen Untersuchungen an Chiodecton cerebriforme Mont., Roccella portentosa (Mont.) Darb. und Roccellaria mollis (Hampe) Zahlbr. können hygroskopische Salzstaubkrusten an Küstenflechten deren Wasserdampfaufnahme fördern. Zwischen Grenzschicht und Flechtenlager vermittelt offenbar ein aktives Transportsystem.     

Zelloberflächenstrukturen der Bacteria und Archaea

Cell wall types of Bacteria and Archaea The acaryote microorganisms are divided into the two domains Bacteria and Archaea. The third domain represent the Eukarya. There is no universal cell wall polymer found in all Bacteria and Archaea. Due to their morphology several cell wall types can be identified, but the chemical diversity of the individual polymers is considerably greater. Certain cell wall polymers are limited to one of the two domains of Bacteria or Archaea like the murein of the Bacteria or the pseudomurein of some methanogens. Peptidoglycans (murein, pseudomurein) do not occur in eukaryotes. On the other hand individual cell wall polymers possess similarities to polymers of other domains. The structural principle of the methanochondroitin is also implemented in the eukaryotic connective tissue. The cell wall polymers consist frequently of glycoconjugates in which the amino acid content (glycoproteins) or the glycan moiety (proteoglycan‐like polymers) predominate. Both components (carbohydrates, amino acids) can also occur in similar amounts (peptidoglycan). There exist also cell wall polymers, which consist only of glycans (slimes, methanochondroitin) or amino acids (proteins, poly‐γ‐D‐glutamyl polymers). Cell wall‐free species (Mycoplasma) also occur. The chemical composition of the cell surface polymers was one of the first phenotypic characteristics that supported the 16 sRNA concept of Carl Woese to assign acaryote organisms into the two domains Bacteria and Archaea. A common feature of all Archaea is the lack of muramic acid and an outer membrane. The later occurs in the gramnegative Bacteria. During the evolution of Bacteria and Archaea a great variety of chemically different cell wall polymers has been developed which allow the growth and interaction of Bacteria and Archaea in different habitats. In this paper, some important surface polymers of Bacteria and Archaea are presented according to their chemical composition.     

Beiträge zur Taxonomie und Chorologie der mitteleuropäischen Utricularia-Arten 2. Androsporogenese,Chromosomenzahlen und Pollenmorphologie

• 1 Microsporogenesis and pollen development in U. vulgaris L., U. intermedia Hayne, and U. minor L. occur typically. In U. australis R. Br., U. ochroleuca Hartm., and U. bremii Heer formation of micronuclei, micropollen, of polyades and abortion of pollen were observed. These aberrations may be responsible for the often affirmed sterility of the mentioned taxa.
• 2 In U. vulgaris L., U. australis R. Br., U. intermedia Hayne, U. ochroleuca Hartm., and U. minor L. the number of chromosomes is n = 22. In U. australis R. Br. and U. ochroleuca Hartm. we occasionally counted n = 18, 19, 20, 23 or 24 chromosomes.
• 3 The pollen grains of all species but U. bremii Heer are 10–19-stephanocolporate. The endoapertures form an endocolpus transversalis; syncolpy of the ectoapertures occurs here and there. The size of normal pollen grains is for the polar axis 25–45 μm, for the equatorial diameter 22–38 μm. The exine is punctitectate; bacules infratectales occur.
• 4 The pollen grains of U. bremii Heer are irregularily spiroaperturate. Their surfaces look like the windings of the brain.
• 5 The pollen grains of the centraleuropean species represent the most derived type of the genus.