Autofluorescence of the fruiting body of the fungus <Emphasis Type="Italic">Macrolepiota rhacodes</Emphasis>

The autofluorescence (primary fluorescence, AF) of the freshly collected fruiting bodies of the fungus Macrolepiota rhacodes was studied in a Zeiss Jenalumar fluorescence microscope at a blue and a green excitation. The strongest yellow AF at blue excitation was displayed by irregular granules on the surface of the fungal pileus. A weaker yellow-green AF was exhibited by spherical cells and hyphae in the central part of the pileus while basidiospores emitted somewhat stronger AF. At green excitation, a considerable red AF was emitted only by basidiospores, other parts of the pileus showing a very weak red AF. M. rhacodes AF is much weaker than the AF of wood-rotting fungi, such as Fomes fomentarius, Daedalea quercina, Piptoporus betulinus, Fomitopsis pinicola and others.     

A glimpse at future forests: predicting the effects of <Emphasis Type="Italic">Phytophthora ramorum</Emphasis> on oak forests of southern Appalachia

The highly pathogenic Phytophthora ramorum, causal organism of sudden oak death (SOD), is established in forests of the Pacific Northwest (USA) and is threatening invasion of other regions. Given the breadth of its host range, with dozens of asymptomatic ornamental hosts and with oaks, Quercus spp., in the red oak (Erythrobalanus) subgenus particularly susceptible, we investigated the consequences of its invasion and establishment in oak-dominated deciduous forests of the eastern USA. We evaluated the nature and extent of pathogen invasion using vegetation assessments coupled with growth simulations. The woody plant community was assessed in three strata (upper, mid- and lower) and was used to characterize forest composition and structure. Using the Forest Vegetation Simulator (FVS), we then projected woody vegetation growth 50 years into the future with and without the effects of SOD. In forest simulations lacking pathogen invasion, little change in composition or structure is forecasted. Both red oaks and white oaks (subgenus Leucobalanus) increase slightly but significantly over the length of the simulation. In contrast, in SOD-affected forests our projections predict a significant loss of red oaks within 10 years of pathogen invasion. Basal area of white oaks and non-oaks is expected to increase more so in the absence of red oaks. The loss of red oaks to pathogen infection will result in greater increases in red maple, Acer rubrum, and yellow poplar, Liriodendron tulipifera, than in forests free of SOD. Loss of red oak represents a significant loss of hard mast, with potentially devastating consequences for wildlife. Red oak loss will also affect decomposition rates, nutrient cycling, forest structure, and timber values, with consequences for forest health and sustainability.     

Regulation of eye and jaw colouration in three‐spined stickleback Gasterosteus aculeatus

Fish can change their skin and eye colour for background matching and signalling. Males of Gasterosteus aculeatus develop ornamental blue eyes and a red jaw during the reproductive season, colours that are further enhanced during courtship. Here, the effects of different hormones on physiological colour changes in the eyes and jaws of male and female G. aculeatus were investigated in vitro. In an in vivo experiment, G. aculeatus were injected with a receptor blocker of a pivotal hormone (noradrenaline) that controls colour change. In males, noradrenaline had aggregating effects on melanophore and erythrophore pigments resulting in blue eyes and a pale jaw, whereas melanocyte‐concentrating hormone (MCH) and melatonin resulted in a pale jaw only. When noradrenalin was combined with melanocyte stimulating hormone (MSH) or prolactin, the jaw became red, while the eyes remained blue. In vivo injection of yohimbine, an alpha‐2 adrenoreceptor blocker, resulted in dispersion of melanophore pigment in the eyes and inhibited the blue colouration. Altogether, the data suggest that noradrenalin has a pivotal role in the short‐term enhancement of the ornamental colouration of male G. aculeatus, potentially together with MSH or prolactin. This study also found a sex difference in the response to MCH, prolactin and melatonin, which may result from different appearance strategies in males, versus the more cryptic females.     

The fluctuating world of a tundra predator guild: bottom‐up constraints overrule top‐down species interactions in winter

Global warming is predicted to change ecosystem functioning and structure in Arctic ecosystems by strengthening top‐down species interactions, i.e. predation pressure on small herbivores and interference between predators. Yet, previous research is biased towards the summer season. Due to greater abiotic constraints, Arctic ecosystem characteristics might be more pronounced in winter. Here we test the hypothesis that top‐down species interactions prevail over bottom‐up effects in Scandinavian mountain tundra (Northern Sweden) where effects of climate warming have been observed and top‐down interactions are expected to strengthen. But we test this ‘a priori’ hypothesis in winter and throughout the 3–4 yr rodent cycle, which imposes additional pulsed resource constraints. We used snowtracking data recorded in 12 winters (2004–2015) to analyse the spatial patterns of a tundra predator guild (arctic fox Vulpes lagopus, red fox Vulpes vulpes, wolverine Gulo gulo) and small prey (ptarmigan, Lagopus spp). The a priori top‐down hypothesis was then tested through structural equation modelling, for each phase of the rodent cycle. There was weak support for this hypothesis, with top‐down effects only discerned on arctic fox (weakly, by wolverine) and ptarmigan (by arctic fox) at intermediate and high rodent availability respectively. Overall, bottom‐up constraints appeared more influential on the winter community structure. Cold specialist predators (arctic fox and wolverine) showed variable landscape associations, while the boreal predator (red fox) appeared strongly dependent on productive habitats and ptarmigan abundance. Thus, we suggest that the unpredictability of food resources determines the winter ecology of the cold specialist predators, while the boreal predator relies on resource‐rich habitats. The constraints imposed by winters and temporary resource lows should therefore counteract productivity‐driven ecosystem change and have a stabilising effect on community structure. Hence, the interplay between summer and winter conditions should determine the rate of Arctic ecosystem change in the context of global warming.     

Trail system in red wood ants (<Emphasis Type="Italic">Formica rufa</Emphasis> Group) under recreation press

The influence of recreation press on the forager trail system in red wood ants was examined. The model settlement of these ants was situated in green moss-pine forest, comprising areas with a different degree of the recreation press. In 2007, trail systems of 36 anthills were mapped (a total of 136 trails). In 2009, two nests from each group at each digression stage were selected as model objects. These nests possessed close to average values of the cupola diameter (d) and the number of trophic trails (n _c ). In these 6 model nests, trail systems (a total of 33 trails) were re-mapped and the strength of columns was estimated. It had been found that the recreation press decreases the population number in families of red wood ants. Trophic trails become shorter, their structure is simplified, and the number of trees with aphid colonies decreases. When the size of the family decreases owing to irregular decrease in the population number of separate columns, columns possessing non-ramified (less “efficient”) trails disappear first. Weakening of the family decreases the mobility of the trail network; trees with aphid colonies become more important.     

Temperature increase and fluctuation induce phytoplankton biodiversity loss – Evidence from a multi‐seasonal mesocosm experiment

Global climate change scenarios predict lake water temperatures to increase up to 4°C and extreme weather events, including heat waves and large temperature fluctuations, to occur more frequently. Such changes may result in a reorganization of the plankton community structure, causing shifts in diversity and structure toward a community dominated by fewer species that are more adapted to endure warmer and irregular temperature conditions. We designed a long‐term (8 months) mesocosm experiment to explore how ambient water temperature (C: control), induced increased temperature (T: +4°C), and temperature fluctuations (F: ±4°C relative to T) change phytoplankton phenology, taxonomical diversity, and community structure, and how such changes affected zooplankton abundance and composition. Synthesis. Our results show that T and F relative to C significantly decreased phytoplankton diversity. Moreover, there was a clear effect of the temperature treatments (T and F) on phytoplankton size structure that resulted in a significantly lower growth of large species (i.e., large Chlorophyta) compared to C. Decreased diversity and evenness in the T and F treatments pushed the community toward the dominance of only a few phytoplankton taxa (mainly Cyanobacteria and Chlorophyta) that are better adapted to endure warmer and more irregular temperature conditions. The observed shift toward Cyanobacteria dominance may affect trophic energy transfer along the aquatic food web.     

Indirect genetic effects in a sex‐limited trait: the case of breeding time in red‐billed gulls

Female reproductive performance can be strongly affected by male care, so that breeding time, a trait expressed only by females, can be seen as one trait determined by both male and female genotypes. Animal model analyses of a 46‐year study of red‐billed gulls (Larus novaehollandiae scopulinus) revealed that laying date was not heritable in females (h² = 0.001 ± 0.030), but significantly so in males (h² = 0.134 ± 0.029). Heritability of breeding time in males probably reflects genetic variability in some other trait such as courtship feeding ability. In line with predictions of evolutionary models incorporating indirect genetic effects, the strong and consistent directional selection for advanced breeding time has not resulted in detectable selection response in males. Our results demonstrate that a female trait is largely determined by genetic characteristics of its mate, and hence, any evolutionary change in red‐billed gull breeding time depends critically on genetic variation in males.     

Effects of Different Spectra from LED on the Growth,Development and Reproduction of <i>Arabidopsis thaliana</i>

Light is the major source of energy for plants and as such has a profound effect on plant growth and development. Red and blue lights have been considered to best drive photosynthetic metabolism and are beneficial for plant growth and development, and green light was seen as a signal to slow down or stop. In this study, Arabidopsis thaliana (Arabidopsis) was used to investigate the effects of red, blue and green lights on the growth and development of plants from seed germination to seeding. Results demonstrated that red light showed a promotion effect but blue light a prohibition one in most stages except for the flowering time in which the effect of each light was just reversed. When mixed with red or blue light, green light generally at least partially cancelled out the effects caused by each of them. Results also showed that the same number of photons the plant received could cause different effects and choosing the right combination of different color of lights is essential in both promoting the growth and development of plants and reducing the energy consumption of lighting in plant factory.     

Tooth replacement in the bowfin (Amia calva — Holostei)

The dissected tooth bearing bones of 20 specimens of Amia calva (Pisces:Holostei) ranging from the third to tenth season have been examined radiographically and in alizarin red S stained and cleared specimens. Although forms of alternate (1:1) tooth series replacement (sensu Edmund, '60) were frequently observed, even in the youngest, immature specimens, many examples of irregular replacement were recorded. In several bones, the maxillae in particular, series with every third (2:1) or fourth (3:1) tooth replacing were seen and possible patterns of 2:2, were recorded. It is concluded that these data are not consistent with the Zahnreihen concept but support a morphogenic field concept of tooth development.     

Short‐term effect of selectivity change in a trawling fishery in the Western Mediterranean

The change of mesh size or shape as a management measure to improve selectivity as proposed by the EU should be assessed using actual fishery data, despite being tested experimentally in previous studies. This work was conducted to evaluate the consequences of inserting either a 40‐mm square‐mesh or a 50‐mm diamond‐mesh (instead of the traditional 40‐mm diamond‐mesh) at codends in commercial Spanish trawlers. Landings in terms of biomass, income and catch composition were compared under commercial conditions. Four métiers were identified in the fishery: European hake (Merluccius merluccius), red mullet (Mullus barbatus), red shrimp (Aristeus antennatus) and Norway lobster (Nephrops norvegicus). No significant differences were observed in biomass or income owing to the new mesh in either European hake or red mullet. In contrast, the total biomass of the red shrimp métier and the biomass of the Norway lobster, Nephrops norvegicus, were significantly higher after the selectivity change. Regarding the catch composition, only the European hake métier showed slight – but not significant – changes after using the new mesh. Considering these results, there was no short‐term effect (substantial biological or economic loss) as previous studies had expected. This could possibly be related to a higher performance of the new gear that may compensate for the lower retention of small sizes.     

Late‐glacial recolonization and phylogeography of European red deer (Cervus elaphus L.)

The Pleistocene was an epoch of extreme climatic and environmental changes. How individual species responded to the repeated cycles of warm and cold stages is a major topic of debate. For the European fauna and flora, an expansion–contraction model has been suggested, whereby temperate species were restricted to southern refugia during glacial times and expanded northwards during interglacials, including the present interglacial (Holocene). Here, we test this model on the red deer (Cervus elaphus) a large and highly mobile herbivore, using both modern and ancient mitochondrial DNA from the entire European range of the species over the last c. 40 000 years. Our results indicate that this species was sensitive to the effects of climate change. Prior to the Last Glacial Maximum (LGM) haplogroups restricted today to South‐East Europe and Western Asia reached as far west as the UK. During the LGM, red deer was mainly restricted to southern refugia, in Iberia, the Balkans and possibly in Italy and South‐Western Asia. At the end of the LGM, red deer expanded from the Iberian refugium, to Central and Northern Europe, including the UK, Belgium, Scandinavia, Germany, Poland and Belarus. Ancient DNA data cannot rule out refugial survival of red deer in North‐West Europe through the LGM. Had such deer survived, though, they were replaced by deer migrating from Iberia at the end of the glacial. The Balkans served as a separate LGM refugium and were probably connected to Western Asia with genetic exchange between the two areas.     

Comparison between <Emphasis Type="Italic">Compsopogon coeruleus</Emphasis> and <Emphasis Type="Italic">Porphyra yezoensis</Emphasis> in their O<Subscript>2</Subscript> evolution rates and phycobilisome composition

In order to investigate the possible effects of the ecological environment on photosynthetic activity and the major light harvesting complex, the oxygen evolution rates and composition of phycobilisome from marine red alga Porphyra yezoensis Ueda and freshwater red alga Compsopogon coeruleus (Balbis) Montagne, which could grow and reproduce under salinity up to 35 ppt, were studied. The results showed that the oxygen evolution rate of P. yezoensis in seawater was significantly higher than that of C. coeruleus in freshwater, and P. yezoensis tolerated inorganic ions at a relatively higher concentration than C. coeruleus. Moreover, the phycoerythrin (PE) of P. yezoensis was R-phycoerythrin containing α, β, and γ subunits comprised phycoerythrobilin and phycourobilin. In contrast, the PE from C. coeruleus consisted of α, β, and γ subunits comprised only phycoerythrobilin but not phycourobilin, suggesting that the PE from C. coeruleus was of a new type. This text was submitted by the authors in English.     

Phytoextraction of cadmium and physiological changes in <Emphasis Type="Italic">Solanum nigrum</Emphasis> as a novel cadmium hyperaccumulator

It is still difficult to fully understand the physiological, biochemical, and molecular mechanisms involved in metal hyperaccumulation and how plants adjust to an adverse environment. Solanum nigrum L. is a novel Cd-hyperaccumulator, which antioxidant defense and photosynthetic CO₂ fixation were investigated in this study. The results showed that the elevated heavy metal concentration, inhibiting S. nigrum growth, was accompanied by a decrease in the photosynthetic CO₂ fixation. The presence of heavy metal in soil led to disturbances in the antioxidant responses, especially in superoxide dismutase, malondialdehyde, phytochelatins, and total acid-soluble thiols, which indices in S. nigrum were significantly correlated with the elevated heavy metal concentration. Whereas peroxidase activity in S. nigrum showed a slight difference and irregular change, reduced glutathione significantly decreased with increasing culturing time and elevated Cd concentration. Thus, the manipulation of antioxidant enzyme activities increases tolerance, thereby potentially increasing the uptake capacity of an organism.     

Light Intensity Affects the Coloration and Structure of Chimeric Leaves of <i>Ananas comosus</i> var<i>. bracteatus</i>

Ananas comosus var. bracteatus is an important ornamental plant because of its green/white chimeric leaves. The accumulation of anthocyanin makes the leaf turn to red especially in the marginal part. However, the red fades away in summer and winter. Light intensity is one of the most important factors affecting leaf color along the seasons. In order to understand the effects of light intensity on the growth and coloration of the chimeric leaves, Ananas comosus var. bracteatus was grown under full sunlight, 50% shade and 75% shade for 75 days to evaluate the concentration of pigments, the color parameters (values L*, a*, b*) and the morpho-anatomical variations of chimeric leaves. The results showed that a high irradiance was beneficial to keep the chimeric leaves red. However, prolonged exposure to high irradiance caused a damage, some of the leaves wrinkled and even burned. Shading instead decreased the concentration of anthocyanin and increased the concentration of chlorophyll, especially in the white marginal part of the leaves. Numerous chloroplasts were observed in the mesophyll cells of the white marginal part of the chimeric leaves under shading for 75 days. The increase in chlorophyll concentration resulted in a better growth of plants. In order to balance the growth and coloration of the leaves, approximately 50% shade is suggested to be the optimum light irradiance condition for Ananas comosus var. bracteatus in summer.     

The control of red colour by a family of MYB transcription factors in octoploid strawberry (Fragaria × ananassa) fruits

Octoploid strawberry (Fragaria × ananassa Duch.) is a model plant for research and one of the most important non‐climacteric fruit crops throughout the world. The associations between regulatory networks and metabolite composition were explored for one of the most critical agricultural properties in octoploid strawberry, fruit colour. Differences in the levels of flavonoids are due to the differences in the expression of structural and regulatory genes involved in flavonoid biosynthesis. The molecular mechanisms underlying differences in fruit colour were compared between red and white octoploid strawberry varieties. FaMYB genes had combinatorial effects in determining the red colour of fruit through the regulation of flavonoid biosynthesis in response to the increase in endogenous ABA at the final stage of fruit development. Analysis of alleles of FaMYB10 and FaMYB1 in red and white strawberry varieties led to the discovery of a white‐specific variant allele of FaMYB10, FaMYB10‐2. Its coding sequence possessed an ACTTATAC insertion in the genomic region encoding the C‐terminus of the protein. This insertion introduced a predicted premature termination codon, which suggested the loss of intact FaMYB10 protein playing a critical role in the loss of red colour in white octoploid strawberry.     

Red And far‐red regulation of filament movement correlates with the expression of phytochrome and FHY1 genes in Spirogyra varians (Zygnematales,Streptophyta)1

Spirogyra filaments show unique photomovement that differs in response to blue, red, and far‐red light. Phototropins involved in the blue‐light movement have been characterized together with downstream signaling components, but the photoreceptors and mechanical effectors of red‐ and far‐red light movement are not yet characterized. The filaments of Spirogyra varians slowly bent and aggregated to form a tangled mass in red light. In far‐red light, the filaments unbent, stretched rapidly, and separated from each other. Mannitol and/or sorbitol treatment significantly inhibited this far‐red light movement suggesting that turgor pressure is the driving force of this movement. The bending and aggregating movements of filaments in red light were not affected by osmotic change. Three phytochrome homologues isolated from S. varians showed unique phylogenetic characteristics. Two canonical phytochromes, named SvPHY1 and SvPHY2, and a noncanonical phytochrome named SvPHYX2. SvPHY1 is the first PHY1 family phytochrome reported in zygnematalean algae. The gene involved in the transport of phytochromes into the nucleus was characterized, and its expression in response to red and far‐red light was measured using quantitative PCR. Our results suggest that the phytochromes and the genes involved in the transport system into the nucleus are well conserved in S. varians.     

Temporal pattern of floral color change and time retention of post‐change flowers in Weigela japonica var. sinica (Caprifoliaceae)

Abstract Floral color changes are common in Weigela and the retention of post‐change flowers has been interpreted as a mechanism to increase attractiveness from a long distance and shorten pollinators’ lingering time on the inflorescence(s) of individual plants. In the present study, we investigated the temporal pattern of floral color change and time required for pollen tube growth in the shrub Weigela japonica var. sinica. Over the 4‐day anthesis, the color of the corolla in this species changes from white to red and the color cue changes from yellow to purple. The duration of both the white phase and the intermediate phase is approximately 1 day and the duration of the red phase is approximately 2 days. Our studies showed that color change in Weigela japonica var. sinica is age‐dependent but independent of pollinator visits and flower pollination. Post‐change flowers lost most of both the male and female residual reproductive ability and retained no rewards for pollinators. It took at least 3 days for a pollen tube to grow to the ovules and achieve fertilization. Thus, retention of post‐change flowers is necessary for the completion of pollen tube growth. Our results indicate that the temporal pattern of color change and time requirement for pollen tube growth are most likely related events.     

Twofold effect of blue light on a circadian rhythm in Acetabularia

Abstract

The circadian chloroplast migration in Acetabularia mediterranea was monitored by continuously measuring the transmission of the cells near the apex. Under continuous red light the amplitude of the rhythm decreased rapidly within a few days. However, circadian changes of chloroplast density were still detectable even after 28 days of red light, indicating the persistence of the rhythm. When blue light was added after red light preirradiation of several days phase shifts were observed which were expressed as advances as well as delays. The period of the rhythm proved to be strongly dependent on the intensity of the continuous blue light which was given in addition to red light. Different red light intensities did not change the period. The occurrence of both effects indicates that the sensory transduction of blue light photoreception in Acetabularia works in two different ways: quanta counting processes and processes of light intensity measurement.