Reversion of anomalous forms ofBacillus subtilis

Anomalous forms ofBacillus subtilis A 32 produced by prolonged cultivation in a chemostat under nitrogen limitation are described. A change in the cultivation conditions brings about a transformation of these forms to bacillar rods. The transformation is gradual and lasts for several generations.     

Sucrose effects on in vitro fruiting and seed production of Centaurium pulchellum

The effect of sucrose on fruiting, seed production, and seed germination of lesser centaury [Centaurium pulchellum (Sw.) Druce] was examined using explants of flowers and flower buds. Sucrose concentrations in the culture medium ranged from 0.003 to 0.3 M. It has been shown that the number of auxiliary buds, capsules dimension, number of viable seeds per capsule and seed dimensions increased with the increase of sucrose concentrations. The highest values were recorded at sucrose concentrations higher than 0.03 M, except for seeds size, which were larger at sucrose concentration ranging from 0.003 to 0.1 M. The germination of in vitro produced seeds was affected by previous culture history: a higher germination percentage was obtained in seeds that were raised from explants originally grown on medium with sucrose concentrations higher than 0.003 M.     

Impact of abscisic acid in overcoming the problem of albinism in horse chestnut androgenic embryos

Horse chestnut (Aesculus hyppocastanum L., Hyppocastanacea) is a relict species with a slow and complex reproductive cycle considered to have horticultural and medical importance. The cycle maybe circumvented via in vitro androgenesis. Androgenesis of horse chestnut was induced in microspores and anther culture on MS media. Some of the horse chestnut androgenic embryos were albinos. Addition of abscisic acid in media (in concentrations of 0.01, 0.1, 0.5, 1, 2, 5, 10, and 20 mg l^?1) with horse chestnut androgenic embryos has circumvented the reproduction cycle barriers. The best results were achieved on medium with the lowest abscisic acid concentration (0.01 mg l^?1) in microspore culture. The microspore culture proved to be a better model system for embryo production and albino embryo reduction than anther culture. Flow cytometry analysis after maturation treatments induced by ABA showed that 88 % of green embryos originating from microspore culture were haploid. However, 50 % of green embryos from anther culture were haploid. The remaining analyzed androgenic embryos, from both types of cultures were diploid.     

Calreticulin mRNA and protein are localized to protein bodies in storage maize callus cells

Maize callus cells possess numerous protein bodies which develop as sub-compartments of the endoplasmic reticulum. We localized maize calreticulin mRNAs and protein in maize callus cells using in situ hybridization and immunocytochemistry. Calreticulin mRNAs were selectively targeted to the endoplasmic reticulum (ER) subdomains surrounding protein bodies. Profilin mRNAs, used as a positive control for in situ hybridization experiments, showed distinct and rather diffuse localization pattern. Using both, immunofluorescence and immunogold electron microscopy localization techniques, calreticulin was found to be enriched around and within protein bodies in maize callus storage cells. As a positive control for reticuloplasmins, HDEL antibody revealed labelling of protein bodies and of the nuclear envelope. The identity of protein bodies was confirmed by specific binding of an α zein antibody. These data suggest that calreticulin mRNA is targeted towards protein body forming subdomains of the ER, and that calreticulin is localized and enriched in these protein bodies. The possibility that calreticulin plays an important role in zein retention within the ER and/or its assembly and packaging into protein bodies during protein body biogenesis in maize callus is discussed.     

The return of an experimentally N-saturated boreal forest to an N-limited state: observations on the soil microbial community structure,biotic N retention capacity and gross N mineralisation

Background and aims

To find out how N-saturated forests can return to an N-limited state, we examined the recovery of biotic N sinks under decreasing N supply.

Methods

. We studied a 40-year-old experiment in Pinus sylvestris forest, with control plots, N0, three N treatments, N1-N3, of which N3 was stopped after 20 years, allowing observation of recovery.

Results

In N3, the N concentration in foliage was still slightly elevated, but the N uptake capacity of ectomycorrhizal (ECM) roots in N3 was no longer lower than in N0. Per area the amount of a biomarker for fungi, here mainly attributed ECM, was higher in N3 and N0 than in N1 and N2. Retention of labeled ¹⁵NH₄ ⁺ by the soil was greater in the control (99 %) and N3 (86 %), than in N1 (45 %) and N2 (29 %); we ascribe these differences to biotic retention because cation exchange capacity did not vary. Gross N mineralisation and retention of N correlated, negatively and positively, respectively, with abundance of ECM fungal biomarker.

Conclusions

. The results suggest a key role for ECM fungi in regulating the N cycle. We propose, in accordance with plant C allocation theory, that recovery is driven by increased tree below-ground C allocation to ECM roots and fungi.     

A review of Turkish saproxylic beetles from the European Red List

The conservation of beetles that depend on dying or dead wood (i.e. saproxylic), has received a great deal of attention in many parts of the world in recent years. Human activities such as urbanization and logging, and their results, e.g. global warming, destroy natural ecosystems and threaten unusual species such as Lucanus cervus (L. 1758), Rosalia alpina (L. 1758), Limoniscus violaceus (Müller 1821) and Osmoderma eremita (Scopoli 1763). Attempts have been made to conserve the habitats upon which these species depend. Although represented by a large number of species, saproxylic beetles in Turkey have not received much attention. Although some Turkish studies have acknowledged their value, comprehensive investigations of these species are very limited. The aim of this study is to make a list, from the literature, of the species that are endangered in Europe and found in Turkey, to highlight the importance of these species. The research includes 151 saproxylic beetle species belonging to the families Bostrichidae, Cerambycidae, Elateridae, Eucnemidae, Scarabaeidae, Euchiridae, Lucanidae and Mycetophagidae. The list of Turkish saproxylic beetles was prepared using the European Red List of Saproxylic Beetles. Information is provided about the IUCN Red List category in Europe, the locations of the species in Turkey, and their global geographic range. We gathered all data about these species from the international literature. Furthermore, we also include in the list certain species whose locations are not specified, but which inhabit Turkey. We obtained their records from some catalogs in Turkey. In addition to the list, we prepared three distribution maps for Turkey. The maps show distribution in Turkey of some species in the Endangered, Vulnerable and Near Threatened categories in the European Red List. It is expected that this study will lead to comprehensive studies on saproxylic beetles from Turkey.