Rejskovití hmyzožravci (čeleď Soricidae) jsou drobní savci, kterých si v přírodě často sotva všimneme. Vyznačují se však mnoha zajímavostmi, díky kterým rozhodně stojí za naši pozornost. K těmto zajímavostem lze zařadit i schopnost echolokace, tj. schopnost orientovat se v prostoru za pomoci ozvěn cvakání, které vydávají. Kromě cvakání se během pohybu prostředím patrně orientují i pomocí štěbetavých hlasů. Bělozubky hnědé (Suncus murinus) při pohybu v neznámém prostředí také „duní“. Zda se i toto dunění uplatňuje při orientaci v prostoru není zatím jasné. Bělozubky pouštní (Diplomesodon pulchellum) zase při přechodu mezi různými typy substrátu vibrují, a tyto vibrace vytvářené celým tělem jim pravděpodobně pomáhají odhadnout vlastnosti substrátu a vyhnout se tak zbytečnému hrabání v hustém písku., Shrews (Soricidae) are small mammals that can be barely noticed in nature. However, there are many interesting facts that make them noteworthy, including echolocation - the ability to navigate with the help of echoes of the clicks they produce. Apart from the clicks, twitters are also probably used for navigation. The Asian House Shrew (Suncus murinus) moving through an unfamiliar environment produces boom, but it is not yet clear whether this sound is used for navigation. The Piebald Shrew (Diplomesodon pulchellum) produces body vibrations in response to a change in the substrate under their feet. These vibrations may be used for exploration of substrate density to avoid digging in dense sand., and Irena Schneiderová.
Rejskovití hmyzožravci (Soricidae) vydávají v nejrůznějších situacích mnoho typů hlasů. Dospělí jedinci se ozývají, pokud jsou v nebezpečí nebo se dostanou do potyčky s jiným jedincem svého druhu, během námluv a páření nebo při kontaktu s potomky. Také mláďata vydávají nejrůznější hlasy, jimiž se často snaží upozornit na své strádání nebo udržet kontakt s matkou a sourozenci. Přestože v poslední době přibývá publikací zabývajících se problematikou akustické komunikace rejskovitých, je to stále poměrně neprobádaná oblast. Mnohé otázky by mohly být zodpovězeny studiem bělozubky hnědé (Suncus murinus), která dobře prospívá i v péči člověka., Shrews (Soricidae) utter many types of vocalization in various situations. Adult individuals emit vocalizations when they are in danger or in a fight with conspecifics, during courtship and mating or when they keep contact with their offspring. Juveniles utter variable vocalizations mostly to prevent their discomfort and to keep contact with their mother and siblings. Although the number of publications has increased recently, acoustic communication among shrews still remains a quite unexplored field. Our knowledge might be significantly expanded by studying the Asian House Shrew (Suncus murinus), a species that can be successfully kept and bred in captivity., and Irena Schneiderová.
Rove beetles (Staphylinidae) are used to explore the forces that shaped the terrestrial fauna on Læsø, a young ca. 3000 year old Danish oceanic island located in the Kattegat strait between mainland Denmark and Sweden. We compile a detailed list of species of rove beetles for Læsø (328 species) and the surrounding Danish and Swedish regions (altogether 1075 species), which includes a standardized inventory of their body sizes, and the habitat and microhabitat preference of each species. The composition of the fauna on Læsø and adjacent mainland regions points to North-Eastern Jutland as the main source of the rove beetles on Læsø. Although large beetles are more active and likely to disperse than small beetles, there is no bias towards large species on the island indicating that the sea separating Læsø from the mainland has not been a barrier for rove beetle dispersal. The statistical analysis of the habitat and microhabitat preferences of the species of the entire system studied has shown that Læsø, compared to the mainland areas, is distinctly more dominated by ecological generalists, especially by species adapted to ephemeral, temporary humid microhabitats. Presumably, the mosaic of mostly dry open habitats available on Læsø filters for species, that are able to populate these suboptimal habitats via patches of humid but ephemeral microhabitats. A comprehensive eco-faunistic dataset for the Staphylinidae compiled for this study is the first modern account of the rove beetle fauna on the Danish island of Læsø., Aslak K. Hansen, Mathias J. Justesen, Sebastian Kepfer-Rojas, David B. Byriel, Jan Pedersen, Alexey Solodovnikov., and Obsahuje bibliografii
Velia currens (Fabricius, 1794) and V. gridellii Tamanini, 1947 are two South European species of Veliidae, whose ecology and behaviour are poorly known. The aims of this study were to investigate their life histories, quantify occurrence of wing polymorphism and gather information on their degree of co-occurrence. Nine different populations were regularly surveyed from April to November 2010. Furthermore, a dataset containing information on the occurrence of the two species and the presence of winged morphs at 294 sites was compiled from museum collections, private collections and published literature. No evidence for multivoltinism was detected in either species. However, oviposition and and/or hatching were protracted in time so that early-instar nymphs and adults co-occurred up to midsummer. Although their distributional ranges completely overlap at a large spatial scale, the two species co-occurred only rarely at the same sites and the degree of co-occurrence was lower than expected by chance. Winged specimens were rarely recorded. At least in V. gridellii, the numbers of winged individuals were inversely related to the altitudes of the sites. During the summer, when some of the streams surveyed dried up, several specimens were found in an apparent state of lethargy, under stones. It is hypothesized that the ability to aestivate, coupled with the ability to walk from one site to another may reduce the advantage associated with producing winged forms and account for the low rate of occurrence of macropterism in these species., Fabio Cianferoni and Giacomo Santini., and Obsahuje seznam literatury
Plant density, planting time, harvest timing, and nitrogen influence on short-term gas-exchange properties of carrot cultivars, Topcut and Sugarsnax (Daucus carota L.) were investigated under field conditions. Net photosynthetic rate (PN), stomatal conductance
(gs), and transpiration rate (E) differed significantly with the cultivars studied. Both planting and harvest timing changed the midday PN rates. P N increased as harvest timing advanced regardless of planting time. Late planting combined with late harvesting registered the maximum P N rates (4.5 μmol m-2 s-1). The water-use efficiency (WUE) was altered by temperature at different harvest timings along with the choice of cultivar. Early harvested Sugarsnax had a higher WUE (2.29 mmol mol-1) than TopCut (1.64 mmol mol-1) as Sugarsnax exhibited more stomatal conductance than TopCut. These changes were principally governed by fluctuations observed with air temperature and photosynthetic photon flux density (PPFD) and altered by the sensitivity of the cultivars to ecological factors. Plant density did not affect the photosynthetic gas-exchange parameters. Our results suggest that carrots manage high population density solely through morphological adaptations with no photosynthetic adjustments. Carrot leaves responded to N application in a curvilinear fashion in both cultivars. N did not alter gs, E, or WUE in carrots. N, applied at a rate of 150 kg N ha-1, increased foliar N up to 2.98%. We conclude that 2.98% of foliar N is sufficient to achieve the maximum photosynthetic rates in processing carrots., A. Thiagarajan, R. Lada, A. Adams., and Obsahuje bibliografii
Phosphorus (P) is one of the limiting mineral nutrient elements in the typical steppe of Inner Mongolia, China. In order to find out the adaptive strategy of Caragana microphylla to low soil P status, we grew plants in P-deficient soil in April 2009 and gave a gradient of P addition ranging from 0 to 60 mg(P) kg-1(soil) from May 2010. Leaf traits were measured in September 2010. Both leaf growth and light-saturated photosynthetic rate (P max) were similar among different groups. Leaf nitrogen (N):P ratio indicated that the growth of C. microphylla was not P-limited in most of the Inner Mongolia typical steppe, which had an average soil available P content equal to 3.61 mg kg-1. The optimal P addition was 20 mg(P) kg-1(soil) for two-year-old plants of C. microphylla. Leaf mass area (LMA) and leaf dry matter content (LDMC) were enhanced with low P, and significantly negatively correlated with photosynthetic N-use efficiency (PNUE). Photosynthetic P-use efficiency (PPUE) increased with decreasing soil P and increasing leaf inorganic
P (Pi): organic P (Po) ratio, and showed no significant negative correlation with LMA or LDMC. P max of C. microphylla did not decline so sharply as it was anticipated. The reason for this phenomenon might be due to the increased PPUE through regulating the leaf total P allocation. C. microphylla had high P-use efficiency via both high PPUE and long P-retention time at low-P supply. The adaptation of C. microphylla to low-P supply provided a new explanation for the increased distribution of the species in the degraded natural grassland in Inner Mongolia, China., T. T. Zhao, N. X. Zhao, Y. B. Gao., and Obsahuje bibliografii
Caragana korshinskii Kom. is a perennial xerophytic shrub, well known for its ability to resist drought. In order to study ecophysiological responses of C. korshinskii under extreme drought stress and subsequent rehydration, diurnal patterns of gas exchange and chlorophyll (Chl) fluorescence parameters of photosystem II as well as Chl content were analyzed. Plant responses to extreme drought included (1) leaf abscission and using stem for photosynthesis, (2) improved instantaneous water-use efficiency, (3) decreased photosynthetic rate and partly closed stomata owing to leaf abscission and low water status, (4) decreased maximum photochemical efficiency of photosystem II (PSII) (variable to maximum fluorescence ratio, Fv/Fm), quantum efficiency of noncyclic electron transport of PSII, and Chl a and Chl b. Four days after rehydration, new leaves budded from stems. In the rewatered plants, the chloroplast function was restored, the gas exchange and Chl fluorescence returned to a similar level as control plant. The above result indicated that maintaining an active stem system after leaf abscission during extreme drought stress may be the foundation which engenders these mechanisms rapid regrowth for C. korshinskii in arid environment., D. H. Xu ... [et al.]., and Obsahuje bibliografii
Warming winter and atmospheric nitrogen (N) deposition are expected to have effects on net primary production (NPP) of Chinese fir (Cunninghamia lanceolata) plantation and implications for plantation carbon sequestration. The effects of nongrowing-season warming on plant morphological and physiological traits were investigated in a greenhouse experiment with two-year-old C. lanceolata seedlings. Elevated temperature (ET) during the nongrowing season significantly increased the net photosynthetic characteristics. The strongest effects occurred during warming period from 1 December 2014 to 1 February 2015 (W1). Moreover, the carbohydrate concentration was elevated due to the warming during W1, but it declined during four months of the warming (from 1 December 2014 to 1 April 2015, W2). The seedlings kept under N deposition (CN) showed a positive effect in all the above-mentioned parameters except δ13C. Significant interactions between ET and N deposition were observed in most parameters tested. At the end of the experiment (W2), the seedlings exposed to a combined ET and N deposition treatment exhibited the highest carbon contents. Our results showed that N deposition might ameliorate the negative effects of the winter warming on the carbon content., L. Yu, T. F. Dong, Y. B. Lu, M. Y. Song, B. L. Duan., and Obsahuje bibliografii
Arsenic is a critical contaminant that is released into the environment through geochemical processes and anthropic actions. Two independent hydroponic experiments were performed to evaluate the ecophysiological responses of water hyacinth [Eichhornia crassipes (Mart.) Solms] to As under various stress conditions. In experiment 1, water hyacinth was exposed to As5+ at concentrations of 0, 0.2, 2.0, and 20 mg L-1 for 0, 2, and 4 d; in experiment 2, water hyacinth was exposed at concentrations of 0, 0.025, 0.05, and 0.1 mg L-1 for 0, 10, and 20 d. In both experiments, As accumulation in plant tissue was proportional to its increase in the nutrient solution; As concentrations were higher in roots than in shoots. Detrimental effects of As on gas exchange were observed and were more pronounced in experiment 1. In experiment 1, at the beginning on the second day of exposure, significant decreases of maximum photochemical efficiency of PSII (Fv/Fm), variable chlorophyll fluorescence (Fv/F0), and photosynthetic pigment contents were observed in plants exposed to 2.0 and 20 mg(As5+) L-1. It indicated that damage to the photosynthetic apparatus had occurred. No changes in Fv/Fm, Fv/F0, and contents of photosynthetic pigments were observed in the plants grown in the presence of 0.2 mg(As5+) L-1 (in experiment 1) or after any of the treatments in experiment 2, indicating plant tolerance. Elevated nonphotochemical quenching was observed in experiment 2 after 20 d of exposure to As; it was as a part of protection mechanisms of the photosynthetic apparatus in these plants. The results obtained here indicate that the use of water hyacinth for As5+ removal from highly impacted environments is limited but that it is effective in remediating sites with a low contamination., A. C. Meneguelli-Souza, A. P. Vitória, T. O. Vieira, M. S. O. Degli-Esposti, C. M. M. Souza., and Obsahuje seznam literatury