The influence of drought stress (DS) upon whole-plant water content, water relations, photosynthesis, and water-use efficiency of Hibiscus rosa-sinensis cv. Leprechaun (Hibiscus) plants at three levels of potassium (K) nutritional status were determined after a 21-d gradually imposed DS treatment. Compared to K-deficient plants, adequate K supply improved the leaf water content (LWC) and leaf water relations of Hibiscus by decreasing the Ψ π, and generally sustained rates of net photosynthesis (PN) and transpiration (E), and stomatal conductance (gs), both in DS and non-DS plants. In K-deficient Hibiscus, LWC, turgor potential (Ψ P), and PN, E, and gs as well as instantaneous water-use efficiency, WUE (PN/E) were consistently lower, compared to K-sufficient plants. Carbon isotope discrimination (Δ) was lower (i.e. longterm WUE was greatest) in DS than non-DS plants, but K had no effect on Δ during the 21-d drought treatment period under glasshouse conditions. However, the trend in the Δ value of DS plants suggests that Δ could be a useful index of the response of Hibiscus to DS under glasshouse growing conditions. Thus the incorporation of a properly controlled fertilization regime involving sufficient levels of K can improve the acclimation of PN to low Ψleaf, increase PN/E of Hibiscus, and may have potential benefit for other woody plants species. and J. N. Egilla, F. T. Davies Jr., T. W. Boutton.
We investigated the strategies of four co-occurring evergreen woody species Quercus ilex, Quercus coccifera, Pinus halepensis, and Juniperus phoenicea to cope with Mediterranean field conditions. For that purpose, stem water potential, gas exchange, chlorophyll (Chl) fluorescence, and Chl and carotenoid (Car) contents were examined. We recognized two stress periods along the year, winter with low precipitation and low temperatures that led to chronic photoinhibition, and summer, when drought coincided with high radiation, leading to an increase of dynamic photoinhibition and a decrease of pigment content. Summer photoprotection was related to non-photochemical energy dissipation, electron flow to alternative sinks other than photosynthesis, decrease of Chl content, and proportional increase of Car content. Water potential of trees with deep vertical roots (Q. coccifera, Q. ilex, and P. halepensis) mainly depended on precipitation, whereas water potential of trees with shallow roots (J. phoenicea) depended not only on precipitation but also on ambient temperature. and F. J. Baquedano, F. J. Castillo.
Apple rootstock seedling M.9-T337 was selected to explore the effect of drought stress. The findings indicated that the relative water content of both the leaf and soil gradually decreased with an increase in drought stress. The water-use efficiency of the leaves increased gradually but decreased sharply after 20 d of drought. Changes in the gas-exchange parameters and chlorophyll fluorescence parameters reflected the gradual decrease in the photosynthetic capacity of the plants with drought stress duration. Infrared thermal imaging showed significant temperature differences between the drought-stressed and control plants after 15 d of drought treatment. When irreversible damage occurred under drought stress, the crop water-stress index and relative water content of the leaf and soil were 0.7, 60.5, and 17.8%, respectively. Based on the results, we formulated a drought stress-grade standard. Further, we established that the best time for irrigation is when drought stress reaches grade 3., D. T. Gao, C. Y. Shi, Q. L. Li, Z. F. Wei, L. Liu, J. R. Feng., and Obsahuje bibliografické odkazy
Our previous studies have shown that the combined administration of drugs elevating extracellular adenosine, i.e. dipyridamole (DP) and adenosine monophosphate (AMP), enhances murine hematopoiesis and potentiates the action of granulocyte colony-stimulating factor (G-CSF). In this study, colony-stimulating activity (CSA) of blood serum of mice treated with DP+AMP, G-CSF or all these drugs in combination, i.e. the ability of the sera to stimulate the growth of GM-CFC colonies, was assayed in vitro. Furthermore, the concentration of GM-CSF and IL-6 in the sera was determined. Administration of DP+AMP was found to enhance significantly serum CSA at all time intervals of serum sampling including 24 h after the last injection of the tested drugs. Additive effects of DP+AMP and G-CSF on serum CSA were noted at early intervals after administration of the drugs. Furthermore, IL-6 levels were significantly elevated in the sera of mice which were administered DP+AMP either alone or in combination with G-CSF. Our results show that the effects of DP+AMP are indirect, mediated through the induction of some cytokine(s) and/or growth factor(s) and that extracellular adenosine can act in cooperation with G-CSF. These findings contribute to the further elucidation of the role of adenosine in hematopoiesis., L. Weiterová, M. Hofer, M. Pospíšil, V. Znojil, D. Štreitová., and Obsahuje bibliografii a bibliografické odkazy
Drug abuse during pregnancy is a growing problem in all developed countries all over the world. The drugs easily cross the placental barrier into the fetal body and are present also in the maternal milk. Therefore, it may affect the development of the child pre- as well as postnatally. The effects of prenatal drug exposure are long-lasting and persist until adulthood. The present review summarizes the clinical and experimental evidence showing how opioids and psychostimulants can affect maternal behavior of drug-abusing mother and the development of their offspring., R. Šlamberová., and Obsahuje seznam literatury
In the final decade of the 20th century, reproductive behaviour in the Czech Republic underwent significant changes, which were manifested in, among other things, a decline in the birth rate. Views on the ideal number of children in a family have, conversely, remained consistent in the population over time, and the ideal of the two-child model has been repeatedly identified in sociological studies over the long term. Given the currently very low fertility rate and the continued postponement of childbirth to a later age, it is important to ask whether the proclaimed aspirations for a two-child family will be fulfilled and whether the tendency will be for women to actually have a second child. This article focuses on values associated with children and especially selected factors connected with the decision to have a second child, including an evaluation of the factors that women take into consideration when deciding to have more children. The analysis is based on data from the survey Men and Women in the Czech Republic: Life Courses and Inter-generational Relationships (GGS: Generations and Gender Survey), the first wave of which was conducted in the Czech Republic in 2005, and for the analysis focusing on a second child in the family selected generations of women were chosen.
Nedávné molekulárně biologické studie scinků (Scincidae) severní Afriky, Kanárských ostrovů, jižní Evropy a Blízkého východu ukazují, že Maroko lze považovat za centrum vzniku předků většiny druhů z oblasti Středomoří a Sahary a že má mezi těmito zeměmi druhově nejbohatší zastoupení scinků. Navíc v rámci marocké herpetofauny jde o jednu z nejpočetnějších skupin plazů, a to s nejvyšší mírou endemismu z 20–24 druhů a poddruhů je 9–11 endemických. and Recent molecular studies in skinks (Scincidae) of North Africa, the Canary Islands, southern Europe and the Middle East have shown that Morocco can be considered the centre of origin for most Mediterranean and Saharan species. It is the country with the highest skink species richness in the entire region. In addition, in Morocco, skinks are one of the most numerous reptile groups, with the highest endemism.