The UN General Assembly has declared 2015 the International Year of Soils to raise awareness of the vital importance of soil, which is essential not only for food security and for cultivating plants for feed, fibre, fuel and medicinal products, but also for maintaining biodiversity as it hosts countless organisms. It plays a key role in storing and filtering water, in carbon and other nutrients cycling and performs other irreplaceable ecosystem functions. The Institute of Soil Biology of the CAS Biology Centre carries out biological research into many of those functions of soil in both natural and human–affected environments, including studies of the soil microstructure, soil organism communities and their dynamics and interactions and so on. Researchers at the Institute of Soil Biology focus, among other things, on the contribution of soil fungi to nitrous oxide emissions and on the production of methane. The latter is a potent greenhouse gas and a substantial part of atmospheric methane is produced by anaerobic microorganisms called Archaea found in the soil and in animal digestive tracts, while soil is also a significant methane sink. Research is also being concentrated on the characterization and risk assessment of antibiotic resistance-reservoirs in soil, which is connected with the massive use of antibiotics in the past five decades. Scientists examine ways of preventing the antibiotic resistance spreading in the environment through food chains as well as and on the role played by the soil microflora in those processes, as Doctor Dana Elhottová explains in the corresponding article. and Jana Olivová.
The third and final season of excavation on Pod Hradem Cave (Moravian Karst) reached bedrock at a maximum depth of 3.5 metres, although the bedrock in this part of the cave represents a very steeply sloping wall rather than the cave floor. Radiocarbon dates indicate that the basal layers in this part of the cave were deposited during the late Middle Palaeolithic period. The finding of amber and shell in layer 11 represents a curious discovery, but there is a possibility that these objects represent an intrusion from a different archaeological context., Ladislav Nejman, Lukáš Kučera, Petr Škrdla, Lenka Lisá, Šárka Hladilová, Miroslav Králík, Rachel Wood, Miriam Nývltová Fišáková, Duncan Wright, Marjorie E. Sullivan, Philip Hughes., and Obsahuje seznam literatury
Brassinosteroids (BRs) and polyamines, well-established growth regulators, play a key role in abiotic stress response in plants. In the present study, we examined the role of 24-epibrassinolide (EBL, an active BR) and/or putrescine (Put) in the salt-induced stress in cucumber. The 15-d-old plants were exposed to 100 mM NaCl and they were subsequently treated by exogenous EBL and/or Put. The salt stress reduced significantly plant growth and gas-exchange parameters, and increased proline content and electrolyte leakage in the leaves. Toxic effects induced by salt stress were completely overcome by the combination of EBL and Put. EBL and/or Put treatments improved the growth parameters of the NaCl-treated plants, such as shoot length, root length, fresh and dry mass. Our data also indicated that applications of EBL and Put upregulated the activities of the antioxidant enzymes, such as catalase, peroxidase, and superoxide dismutase under salt stress., Q. Fariduddin, B. A. Mir, M. Yusuf, A. Ahmad., and Obsahuje bibliografii
Seedlings of the hypoxia-sensitive cucumber cultivar were hydroponically grown under hypoxia for 7 d in the presence or absence of 24-epibrassinolide (EBR, 2.1 nM). Hypoxia significantly inhibited growth, while EBR partially counteracted this inhibition. Leaf net photosynthetic rate (PN), stomatal conductance, transpiration rate, and water-use efficiency declined greatly, while the stomatal limitation value increased significantly. The maximum net photosynthetic rate was strongly reduced by hypoxia, indicating that stomatal limitation was not the only cause of the PN decrease. EBR markedly diminished the harmful effects of hypoxia on PN as well as on stomata openness. It also greatly stimulated CO2 fixation by the way of increasing the carboxylation capacity of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco), ribulose-1,5-bisphosphate regeneration, Rubisco activity, and the protection of Rubisco large subunit from degradation. Our data indicated that photosystem (PS) II was damaged by hypoxia, while EBR had the protective effect. EBR further increased nonphotochemical quenching that could reduce photodamage of the PSII reaction center. The proportion of absorbed light energy allocated for photochemical reaction (P) was reduced, while both nonphotochemical reaction dissipation of light energy and imbalanced partitioning of excitation energy between PSI and PSII increased. EBR increased P and alleviated this imbalance. The results suggest that both stomatal and nonstomatal factors limited the photosynthesis of cucumber seedlings under hypoxia. EBR alleviated the growth inhibition by improving CO2 asimilation and protecting leaves against PSII damage., Y. H. Ma, S. R. Guo., and Obsahuje bibliografii