Seed production and seed quality in a calcareous grassland in elevated CO2

In diverse plant communities the relative contribution of species to community biomass may change considerably in response to elevated CO₂. Along with species‐specific biomass responses, reproduction is likely to change as well with increasing CO₂ and might further accelerate shifts in species composition. Here, we ask if, after 5 years of CO₂ exposure, seed production and seed quality in natural nutrient‐poor calcareous grassland are affected by elevated CO₂ (650 μ L L^?1 vs 360 μ L L^?1) and how this might affect long‐term community dynamics. The effect of elevated CO₂ on the number of flowering shoots (+ 24%, P < 0.01) and seeds (+ 29%, P = 0.06) at the community level was similar to above ground biomass responses in this year, suggesting that the overall allocation to sexual reproduction remained unchanged. Compared among functional groups of species we found a 42% increase in seed number (P < 0.01) of graminoids, a 33% increase (P = 0.07) in forbs, and no significant change in legumes (? 38%, n.s.) under elevated CO₂. Large responses particularly of two graminoid species and smaller responses of many forb species summed up to the significant or marginally significant increase in seed number of graminoids and forbs, respectively. In several species the increase in seed number resulted both from an increase in flowering shoots and an increase in inflorescence size. In most species, seeds tended to be heavier (+ 12%, P < 0.01), and N‐concentration of seeds was significantly reduced in eight out of 13 species. The fraction of germinating seeds did not differ between seeds produced in ambient and elevated CO₂, but time to germination was significantly shortened in two species and prolonged in one species when seeds had been produced in elevated CO₂. Results suggest that species specific increases in seed number and changes in seed quality will exert substantial cumulative effects on community composition in the long run.     

Temperature effects on forest herbs assessed by warming and transplant experiments along a latitudinal gradient

Slow‐colonizing forest understorey plants are probably not able to rapidly adjust their distribution range following large‐scale climate change. Therefore, the acclimation potential to climate change within their actual occupied habitats will likely be key for their short‐ and long‐term persistence. We combined transplant experiments along a latitudinal gradient with open‐top chambers to assess the effects of temperature on phenology, growth and reproductive performance of multiple populations of slow‐colonizing understorey plants, using the spring flowering geophytic forb Anemone nemorosa and the early summer flowering grass Milium effusum as study species. In both species, emergence time and start of flowering clearly advanced with increasing temperatures. Vegetative growth (plant height, aboveground biomass) and reproductive success (seed mass, seed germination and germinable seed output) of A. nemorosa benefited from higher temperatures. Climate warming may thus increase future competitive ability and colonization rates of this species. Apart from the effects on phenology, growth and reproductive performance of M. effusum generally decreased when transplanted southwards (e.g., plant size and number of individuals decreased towards the south) and was probably more limited by light availability in the south. Specific leaf area of both species increased when transplanted southwards, but decreased with open‐top chamber installation in A. nemorosa. In general, individuals of both species transplanted at the home site performed best, suggesting local adaptation. We conclude that contrasting understorey plants may display divergent plasticity in response to changing temperatures which may alter future understorey community dynamics.     

Seasonal variations in fat content and fatty acid composition of male and female coregonid' bondella' from Lake Maggiore and landlocked shad from Lake Como (Northern Italy)

The Lake Maggiore bondella Coregonus macrophthalmus use perivisceral adipose tissue for gonadal development (with particular evidence in females), and muscle fat as an energy source. Females use mainly saturated fatty acids (SFA) for energy purposes, while males use monounsaturates (MUFA) also. During vitellogenesis, females can also mobilize fatty acid precursors of gonadal highly unsaturated fatty acids of the ω3 family from muscle tissue, but in both sexes specific retention of docosahexaenoic acid (DHA=22: 6ω3) in muscle is evident. Landlocked shad, unlike several freshwater fishes, can utilize the liver as well as body cavity and muscle as a fat reserve depot. The perivisceral fat stored during the feeding period appears to be utilized mainly for winter energy maintenance requirements. Lipid reserves from liver and muscle are also mobilized to meet the requirements resulting from gonadal development. In particular, females seem to use liver reserves, especially 18: 1ω9, more than males, to meet the demands of ovogenesis. In the muscle, SFA are used mainly for energy purposes. During gonadal development, specific muscular and hepatic ω3 highly unsaturated fatty acids (ω3 HUFA=20: 5 + 22: 5 + 22: 6) and ω6 HUFA (20: 4+22: 4+22: 5) retention is evident in both sexes, while fatty acid precursors of ω3 and ω6 HUFA are mobilized, especially from muscle tissue.     

The kinase activity of PKR represses inflammasome activity

The protein kinase R (PKR) functions in the antiviral response by controlling protein translation and inflammatory cell signaling pathways. We generated a transgenic, knock-in mouse in which the endogenous PKR is expressed with a point mutation that ablates its kinase activity. This novel animal allows us to probe the kinase-dependent and -independent functions of PKR. We used this animal together with a previously generated transgenic mouse that is ablated for PKR expression to determine the role of PKR in regulating the activity of the cryopyrin inflammasome. Our data demonstrate that, in contradiction to earlier reports, PKR represses cryopyrin inflammasome activity. We demonstrate that this control is mediated through the established function of PKR to inhibit protein translation of constituents of the inflammasome to prevent initial priming during innate immune signaling. These findings identify an important role for PKR to dampen inflammation during the innate immune response and caution against the previously proposed therapeutic strategy to inhibit PKR to treat inflammation.     

The Lerhamn drill core and its bearing for the graptolite biostratigraphy of the Ordovician Tøyen Shale in Scania,southern Sweden

Maletz, J. & Ahlberg, P. 2011: The Lerhamn drill core and its bearing for the graptolite biostratigraphy of the Ordovician Tøyen Shale in Scania, southern Sweden. Lethaia, Vol. 44, pp. 350–368. A drill core through the Lower Ordovician Tøyen Shale Formation at Lerhamn, NW Scania, southern Sweden, provides important new information for the precise biostratigraphic resolution of the Floian to lower Darriwilian time interval in southern Scandinavia. The Hunnegraptus copiosus, Tetragraptus phyllograptoides, Cymatograptus protobalticus (new), Baltograptus vacillans (new), Baltograptus sp. cf. Baltograptus deflexus (new), Baltograptus minutus (new), Isograptus victoriae, Undulograptus austrodentatus (Arienigraptus zhejiangensis and Undulograptus sinicus Subzones) and the (?)Corymbograptus retroflexus (new) biozones are differentiated in the core and their correlation in Scania is discussed. The Lerhamn drill core provides the most detailed graptolite record of the Floian Stage in Scandinavia. The interval is dominated by a number of species of the genus Baltograptus, endemic to the Atlantic Faunal realm and highly useful for regional biostratigraphic correlation. The biostratigraphic framework is based on endemic and pandemic faunal elements. The mixture of both elements in the drill core allows a more precise inter‐continental correlation of Lower to Middle Ordovician graptolite faunas and may – in the future – provide information as to the climatic history of regions dominated by Baltograptus faunas in the Floian. The (?)C. retroflexus Biozone is based on species originally described from Bohemia, but the record of the zone in the Lerhamn drill core indicates a wider distribution of its fauna. □Biostratigraphy, graptolites, Ordovician, Scania, Sweden.     

New snakeflies (Insecta: Raphidioptera) from the Lower Cretaceous of the UK,Spain and Brazil

Abstract: Several new taxa of snakeflies (Raphidioptera) are described from the Lower Cretaceous deposits of the Wealden, UK (Barremian), Montsec, Spain (Barremian) and the Crato Formation, Brazil (Aptian). Mesoraphidia ednae sp. nov. and M. hilli sp. nov. are described from the Wealden; Nanoraphidia lithographica sp. nov. and Iberoraphidia dividua gen. et sp. nov. are described from Montsec, and Baissoptera lisae sp. nov. is described from the Crato Formation. The geographical range of Nanoraphidia has potentially been extended.     

The identity of the Ordovician (Darriwilian) graptolite Fucoides dentatus Brongniart, 1828

Abstract: The biostratigraphically important Middle Ordovician (Darriwilian) biserial graptolite Fucoides dentatus Brongniart, 1828 is redescribed and illustrated from its type material and from additional specimens collected at the type locality – Lévis, Quebec, Canada. It is referred to Levisograptus gen. nov., which includes also the austrodentatus group of early axonophoran graptolites. The species has previously been confused with a younger, mid‐Darriwilian species, now referred to as Eoglyptograptus gerhardi sp. nov., and recognized as the type species of the genus Eoglyptograptus Mitchell. Both species can be differentiated easily by their respective proximal development types and show nonoverlapping biostratigraphical ranges. Levisograptus dentatus (Brongniart) is an important biostratigraphical index species in the early Darriwilian. Eoglyptograptus species are found in the higher Darriwilian and are biogeographically restricted to the Atlantic Faunal Realm.     

Phytoplankton patchiness in Winam Gulf,Lake Victoria: a study using principal component analysis of in situ fluorescent excitation spectra

1. In order to characterise phytoplankton patchiness at fine scales, a profiling multiwavelength fluorometer was cast at numerous locations throughout Winam Gulf in Lake Victoria to measure fluorescent excitation spectra, which are indicators of both phytoplankton diversity and coloured dissolved organic matter (CDOM). 2. Processing the spectral data with principal component analysis (PCA) revealed that linear combinations of four fundamental ‘base’ spectra could explain almost all of the variation in spectral measurements. Three of the base spectra were associated with spatially distinct patches of phytoplankton containing different species assemblages, while the fourth base spectrum was due to CDOM fluorescence. 3. The locations of the phytoplankton patches were traced to the south‐east of Winam Gulf, the western end of the Rusinga Channel and the open waters of Lake Victoria adjacent to Winam Gulf, respectively. The high CDOM fluorescence was traced mainly to relatively deep water in the Rusinga Channel. 4. The phytoplankton and CDOM patchiness were interpreted in the context of physical and chemical gradients that were measured at the site at the same scale as the spectral data. Strong relationships were found between the gradients in spectral data and other environmental variables, which suggested several underlying explanations for the phytoplankton and CDOM patchiness.