Trichomes within the Plantaginaceae

A survey of trichome types and their distribution within Plantaginaceae is presented based on a study of 112 species and 30 literary references. 14 different characters were distinguished, some are considered useful for phylogenetic studies. Stomatal types in 32 species are recorded.     

Settling down of seasonal migrants promotes bird diversification

How seasonal migration originated and impacted diversification in birds remains largely unknown. Although migratory behaviour is likely to affect bird diversification, previous studies have not detected any effect. Here, we infer ancestral migratory behaviour and the effect of seasonal migration on speciation and extinction dynamics using a complete bird tree of life. Our analyses infer that sedentary behaviour is ancestral, and that migratory behaviour evolved independently multiple times during the evolutionary history of birds. Speciation of a sedentary species into two sedentary daughter species is more frequent than speciation of a migratory species into two migratory daughter species. However, migratory species often diversify by generating a sedentary daughter species in addition to the ancestral migratory one. This leads to an overall higher migratory speciation rate. Migratory species also experience lower extinction rates. Hence, although migratory species represent a minority (18.5%) of all extant birds, they have a higher net diversification rate than sedentary species. These results suggest that the evolution of seasonal migration in birds has facilitated diversification through the divergence of migratory subpopulations that become sedentary, and illustrate asymmetrical diversification as a mechanism by which diversification rates are decoupled from species richness.     

The epiphytic lichen zones in rural Denmark and Schleswig–Holstein

The epiphytic lichen flora of 332 trees standing at roadsides or in churchyards in non–urban areas of Denmark and Schleswig–Holstein, Federal Republic of Germany, was investigated. The condition of the lichen vegetation in each of 107 subareas was evaluated by means of a nine–point scale largely based upon presence, fertility and vitality of Anaptychia ciliaris and Physconia pulverulacea.
A marked depauperation of the lichen communities of the alliance Xanthorion parietinae is demonstrated in Schleswig–Holstein and is attributed to long–range SO₂ air pollution. No significant pattern of adverse effects on the corresponding communities can be seen in Danish rural areas, but the reduction in frequency and size of Ramalina species in recent times is believed to be the result of background air pollution.
A list of 111 recorded taxa is given and selected species are commented on. Candelariella reflexa (Nyl.) Lettau is reported as new to Denmark. The effects of agricultural spraying and the decrease in the numbers of phorophytes in recent decades are discussed.     

Changes in intracellular composition in response to hyperosmotic stress of NaCl, sucrose or glutamic acid in Brevibacterium lactofermentum and Corynebacterium glutamicum

Changes in intracellular composition after hyperosmotic shock were studied in the lysine-producing mutant Brevibacterium lactofermentum NRRL B-11470 and the wild-type Corynebacterium glutamicum ATCC 13032. Both strains accumulated betaine, proline, glutamic acid, glutamine and trehalose in response to stress. The accumulated amino acids were synthesized by the cells, while betaine and trehalose were taken up from the medium. The contribution of synthesized osmoregulators was highest in C. glutamicum. In a sucrose-limited continuous culture, the increased outer osmotic pressure was balanced within 15 min for C. glutamicum and somewhat later in B. lactofermentum. The rapid regulation was due to both accumulation of osmoregulators, and shrinkage of cell and cytoplasmic volume. Immediately after shock, glutamine and glutamic acid were the dominating osmolytes. During the adaptation process, glutamine was replaced by the better osmoprotectant proline. In betaine-enriched cultures, betaine accumulation increased at the expense of glutamic acid, glutamine and trehalose. The total intracellular concentration of osmolytes increased linearly with increasing stress for all stress factors.