Accumulation des carbohydrates chez les sexués de plusieurs espèces de fourmis en relation avec l'existence ou l'absence d'un vol nuptial

The dispersal strategy of ants generally makes use of a nuptial flight to bring together the sexes. The energy necessary to accomplish this flight comes from stored carbohydrates. However, in some species, one of the sexes does not fly and mating occurs in the nest. This is the case in Iridomyrmex humilis and Cataglyphis cursor, in which the virgin queens possess wings but not leave the natal nest. We show in this work that the winged females of these two species accumulate very little carbohydrate during the maturation period occuring between emergence and mating: expressed as a percentage of dry weight at the time of mating, the total carbohydrates reach only 3.2% in I. humilis and 2.1% in C. cursor. In contrast, the males of these species which fly, possess three to four times more carbohydrates (13.0% and 6.2%, respectively). These latter values are very similar to those found for both sexes of species employing nuptial flights, such several species of wood ants (Formica rufa, F. polyctena, F. lugubris ), Lasius (L. niger , L. flavus ) or Myrmica scabrinodis also studied here. It appears that the absence of the mating flight is associated with reduced levels of carbohydrates, specially glycogen

Fourmis du Vallon de Nant - Premières données

Les auteurs ont procédé à un premier recensement de la diversité en fourmis du Vallon de Nant (Alpes vaudoises, Suisse) lors des premières Journées de la biodiversité organisées les 5 et 6 juillet 2008. Neuf espèces de fourmis ont été récoltées, entre 1240m et 1800m d'altitude. Formica lemani, Formica lugubris et Myrmica ruginodis représentent trois quarts des observations. Toutes les espèces recensées sont communes en montagne

Loss of mating flight and shift in the pattern of carbohydrate storage in sexuals of ants (Hymenoptera; Formicidae)

In ants, energy for flying is derived from carbohydrates (glycogen and free sugars). The amount of these substrates was compared in sexuals participating or not participating in mating flights. Results show that in participating females (Lasius niger, L. flavus, Myrmica scabrinodis, Formica rufa, F. polyctena, F. lugubris), the amount of carbohydrates, especially glycogen, was higher than in non-participating females (Cataglyphis cursor, Iridomyrmex humilis). Similarly, male C. cursor and I. humilis which fly, exhibit a much higher carbohydrate content than do the non-flying females of these species. Furthermore, the quantity of carbohydrates stored was generally higher in males than in females for each species. These results are discussed with regard to the loss of the nuptial flight by some species of ants.

Development of a scar marker for Pierce's Disease strains of Xylella fastidiosa

The objective of this research was to develop a primer for a polymerase chain reaction specific for Xylella fastidiosa strains that cause Pierce's Disease (PD) in grapes (Vitis vinifera). The DNA amplification of 23 different strains of X. fastidiosa, using a set of primers REP1-R (5'-IIIICGICGIATCCIGGC-3') and REP 2 (5'-ICGICTTATCIGGCCTAC-3') using the following program: 94 ºC/2 min; 35 X (94 ºC/1 min, 45 ºC/1 min and 72 ºC/1 min and 30 s) 72 ºC/5 min, produced a fragment of 630 bp that differentiated the strains that cause disease in grapes from the other strains. However, REP banding patterns could not be considered reliable for detection because the REP1-R and REP 2 primers correspond to repetitive sequences, which are found throughout the bacterial genome. The amplified product of 630 bp was eluted from the agarose gel, purified and sequenced. The nucleotide sequence information was used to identify and synthesize an specific oligonucleotide for X. fastidiosa strains that cause Pierce's Disease denominated Xf-1 (5'-CGGGGGTGTAGGAGGGGTTGT-3') which was used jointly with the REP-2 primer at the following conditions: 94 ºC/2 min; 35 X (94 ºC/1 min, 62 ºC/1 min; 72 ºC/1 min and 30 s) 72 ºC/10 min. The DNAs isolated from strains of X. fastidiosa from other hosts [almond (Prumus amygdalus), citrus (Citrus spp.), coffee (Coffea arabica), elm (Ulmus americana), mulberry (Morus rubra), oak (Quercus rubra), periwinkle wilt (Catharantus roseus), plums (Prunus salicina) and ragweed (Ambrosia artemisiifolia)] and also from other Gram negative and positive bacteria were submitted to amplification with a pair of primers Xf-1/REP 2 to verify its specificity. A fragment, about 350 bp, was amplified only when the DNA from strains of X. fastidiosa isolated from grapes was employed.

Multivariate analysis of pollen frequency of the native species Escallonia pulverulenta (Saxifragaceae) in Chilean honeys

The aim of this work was the identification of geographic zones suitable for the production of honeys in which pollen grains of Escallonia pulverulenta (Ruiz & Pav.) Pers. (Saxifragaceae) can be detected. The analysis of botanical origin of 240 honey samples produced between La Serena and Puerto Mont (the IV and X Administrative Regions of Chile), allowed the detection of pollen grains of E. pulverulenta in 46 Chilean honeys. The geographic distribution of the honeys studied is presented together with their affinities, through factor analysis and frequency tables. The study was based on the presence of E. pulverulenta pollen. Escallonia pulverulenta pollen percentages oscillated between 0.24% and 78.5%. Seventeen of the studied samples were designated as unifloral - i.e. samples showing more than 45% pollen of a determined plant species. Two of these corresponded to E. pulverulenta (corontillo, madroño or barraco) honeys. The remaining unifloral honeys correspond to 8 samples of Lotus uliginosus Schkuhr (birdsfoot trefoil), 2 samples of Aristotelia chilensis (Molina) Stuntz (maqui) and 1 sample of Escallonia rubra (Ruiz & Pav.) Pers. (siete camisas), Eucryphia cordifolia Cav. (ulmo or muemo), Weinmannia trichosperma Cav. (tineo), Rubus ulmifolius Schott (blackberry) and Brassica rapa L. (turnip). Honeys with different percentages of E. pulverulenta pollen - statistically analyzed through correspondence analysis - could be associated and assigned to one of three geographic types, defined on the basis of this analysis. The geographical type areas defined were the Northern Mediterranean Zone (samples from the IV Region), Central Mediterranean Zone (samples from the V to the VIII regions including two samples of unifloral Escallonia pulverulenta honey), and Southern Mediterranean Zone (samples from the IX Region).

Microwave-assisted extraction of anthocyanin from Chinese bayberry and its effects on anthocyanin stability

AbstractAnthocyanins are present in high concentrations in Chinese bayberry, Myrica rubra Sieb. & Zucc. Herein, a microwave-assisted extraction was used to extract the anthocyanins from Chinese bayberry. The HPLC chromatogram of the extracts showed that the anthocyanin components were slightly hydrolysed during the extraction process. Further experiments confirmed that microwave irradiation slightly hydrolysed cyanidin-3-O-glucoside to cyanidin, but did not significantly influence the antioxidant activity of the extracts. Optimized extraction conditions for total anthocyanin content were a solid-to-liquid ratio, extraction temperature, and extraction time of 1:50, 80 °C, and 15 min, respectively. Under these conditions, the anthocyanin content was 2.95 ± 0.08 mg·g−1, and the antioxidant activity yield was 279.96 ± 0.1 μmol.·g−1 Trolox equivalent on a dry weight basis. These results indicated that microwave-assisted extraction was a highly efficient extraction method with reduced processing time. However, under some extraction conditions it could damage the anthocyanins. These results provide an important guide for the application of microwave extraction.

Influência de temperatura, substrato e luz na germinação de sementes de bertalha

Esse trabalho foi desenvolvido com o objetivo de avaliar os efeitos da temperatura, substrato e luz na germinação de sementes de bertalha. Inicialmente, foram desenvolvidos três experimentos, testando temperaturas constantes de 20, 25, 30, 35ºC e alternadas de 20-25, 20-30, 20-35, 25-30, 25-35 e 30-35ºC; quatro substratos: rolo de papel toalha, sobre papel de filtro, areia e vermiculita; luz monocromática, comprimentos de ondas do vermelho, vermelho extremo e ausência de luz, isoladamente. E, posteriormente, foi conduzido um quarto experimento, em ensaio fatorial 6x5, onde foram avaliados os substratos rolo de papel toalha RP), sobre papel de filtro, sobre areia, entre areia, sobre vermiculita e entre vermiculita e as temperaturas de 25 e 30ºC constantes e 20-25, 20-30 e 20-35ºC alternadas. O delineamento experimental foi o inteiramente ao acaso, com quatro repetições de 25 sementes. As sementes foram avaliadas quanto à porcentagem e velocidade de germinação. Os resultados evidenciam que as temperaturas de 30ºC constante e 20-30ºC alternadas e o substrato rolo de papel são as melhores condições para germinação das sementes de bertalha. As sementes de bertalha germinam tanto na presença como na ausência de luz, comportando-se como fotoblástica neutra.

Grass-endophyte coevolution and ploidy levels in fescues

ABSTRACT Fescues consist of wild and cultivated grasses that have adapted to a wide range of environmental conditions. They are an excellent model species for evolutionary ecology studies that investigate symbiosis and polyploidization and their effects on plant performance. First, they are frequently infected with symbiotic endophytic fungi known to affect a plant’s ability to cope with biotic and abiotic environmental factors. Second, fescue species have been reported to have substantial intraspecific variation in their ploidy level and morphology. In my thesis, I examined large-scale generalizations for frequency of polyploidy and endophyte infections and their effects on plant morphology. As a model species, I selected red (Festuca rubra) and viviparous sheep’s (F. vivipara) fescues. They are closely related, but they differ in terms of distribution and endophyte infection frequency. I investigated the biogeographic pattern and population biology of 29 red and 12 viviparous sheep’s fescue populations across ≈300 latitudes in Europe (400-690 N). To examine plant ploidy levels, I implemented time- and cost-efficient plate-based high throughput flow cytometric analysis. This efficient procedure enabled me to analyze over 1000 red fescue individuals. I found three ploidy levels among them: overall 84 %, 9 % and 7 % of the red fescue plants were hexaploid, tetraploid and octoploid, respectively. However, all viviparous sheep’s fescue plants were tetraploid. Ploidy level of red fescue appeared to some extent follow gradients in latitude and primary production as suggested by previous studies, but these results could be explained better by taking the sampling design and local adaptation into account. Three Spanish populations were mostly tetraploids and one high elevation population in northernmost Finland (Halti) was octoploid, while most other populations (25 sites) were dominated by hexaploids. Endophyte infection frequencies of wild fescue populations varied from 0 to 81 % in red fescue populations and from 0 to 30 % in viviparous sheep’s fescue populations. No gradients with latitude or primary production of the sites were detected. As taxonomy of red fescues is somewhat unclear, I also studied morphology, ploidy variation and endophyte status of proposed subspecies of European red fescues. Contrary to previous literature, different ploidy levels occurred in the same subspecies. In addition to wild fescues, I also used two agronomically important cultivars of meadow and tall fescue (Schedonorus phoenix and S. pratensis). As grass-legume mixtures have an agronomic advantage over monocultures in meadows, I carried out a mixture/competition experiment with fescues and red clover to find that species composition, nutrient availability and endophyte status together determined the total biomass yield that was higher in mixtures compared to monocultures. The results of this thesis demonstrate the importance of local biotic and abiotic factors such as grazing gradients and habitat types, rather than suggested general global geographical or environmental factors on grass polyploidization or its association with symbiotic endophytic fungi. I conclude that variation in endophyte infection frequencies and ploidy levels of wild fescues support the geographic mosaic theory of coevolution. Historical incidents, e.g., glaciation and present local factors, rather than ploidy or endophyte status, determine fescue morphology.

Distribution spatiale des racines fines, disponibilité de la lumière et rendement dans un système de culture intercalaire avec arbres feuillus en zone tempérée

Les distributions spatiales des racines fines de Quercus rubra L. (CHR), Populus deltoides x nigra (DN3570) (PEH) et d’une culture fourragère (FOUR) ont été étudiées dans un système agroforestier de culture intercalaire (SCI) du sud du Québec (Canada). L’étude ne révèle pas d’enracinement plus profond des arbres en SCI, mais des profils superficiels à l’instar de nombreuses espèces d’arbres en plantations ou en milieu naturel. Une séparation spatiale existe entre les systèmes racinaires du FOUR et des CHR dont la densité relative selon la profondeur est plus faible que celle de la culture de 0 à 10 cm, mais plus élevée de 10 à 30 cm. Les PEH ne présentent pas d’adaptation racinaire et les hautes valeurs de densités de longueur racinaires (FRLD) de surface près du tronc entraînent une diminution de 45 % de la densité racinaire de surface du fourrage, suggérant une forte compétition pour les ressources du sol. L’étude du rendement agricole a d’ailleurs révélé des réductions de biomasse fourragère particulièrement près des PEH. Cependant, les résultats d’une analyse à composantes principales suggèrent un impact secondaire de la compétition racinaire sur le rendement agricole, et une plus grande importance de la compétition pour la lumière. L’impact des PEH à croissance rapide sur la culture est plus grand que celui du CHR. Cependant, ils seront récoltés plus rapidement et l’espace libéré favorisera la croissance de la culture intercalaire. Cet aspect dynamique des SCI les rapproche des écosystèmes naturels et devrait être réfléchi et approfondi pour leur succès futur.

Plants growing on contaminated and brownfield sites appropriate for use in Organisation for Economic Co-operation and Development terrestrial plant growth test

The Organisation for Economic Co-operation and Development (OECD) Terrestrial plant test is often used for the ecological risk assessment of contaminated land. However, its origins in plant protection product testing mean that the species recommended in the OECD guidelines are unlikely to occur on contaminated land. Six alternative species were tested on contaminated soils from a former Zn smelter and a metal fragmentizer with elevated concentrations of Cd, Cu, Pb, and Zn. The response of the alternative species was compared to two species recommended by the OECD; Lolium perenne (perennial ryegrass) and Trifolium pratense (red clover). Urtica dioica (stinging nettle) and Poa annua (annual meadow-grass) had low emergence rates in the control soil so may be considered unsuitable. Festuca rubra (chewings fescue), Holcus lanatus (Yorkshire fog), Senecio vulgaris (common groundsel), and Verbascum thapsus (great mullein) offer good alternatives to the OECD species. In particular, H. lanatus and S. vulgaris were more sensitive to the soils with moderate concentrations of Cd, Cu, Pb, and Zn than the OECD species.

The influence of biostimulants on growth and vitality of three urban tree species following transplanting

Four commercially available, biostimulants sold under the trade names ‘Generate’, ‘Crop Set’, ‘Fulcrum’ and ‘Redicrop 2000’ were applied either as a root drench or foliar spray to three transplant-sensitive tree species, red oak(Quercus rubra), birch(Betula pendula) and beech (Fagus sylvatica) post transplanting. The short and long-term efficacy of the biostimulants on growth was quantified by recording root and shoot vigour at week 8 and 20. In addition, improvements in tree vitality were assessed by measurement of a chlorophyll a performance index based on leaf chlorophyll fluorescence emissions. Irrespective of species, no significant effect of mode of application (foliar spray versus root drench) was recorded on growth and vitality. The biostimulants Generate and Fulcrum increased growth of all three tree species. No significant effects on growth and chlorophyll fluorescence of birch and beech were recorded following applications of the biostimulants Crop Set and Redicrop 2000, however, significant increase in growth of red oak was recorded. Only the biostimulant Generate increased chlorophyll fluorescence values of all test species. Results show use of biostimulants can improve root and shoot vigour following transplanting. However, selection of an appropriate biostimulant is critical as effects on growth and vitality can vary widely between tree species possibly as a result of the differing active ingredient used in the formulation of the product.

Disposition of two names in Almeidea (Rutaceae)

(Disposition of two names in Almeidea (Rutaceae)). Examination of type specimens at the P herbarium showed that Almeidea longifolia A. St.-Hil. (Rutaceae) is an illegitimate substitute name for A. affinis A. St.-Hil. The latter name is proposed here as a heterotypic synonym of A. rubra A. St.-Hil.

Filogenia molecular de fungos gasteroides das ordens Phallales e Geastrales (Phallomycetidae)

Gasteroids fungi are characterized by the basidiospores maturation inside the basidioma, from which spores liberation occurs in a passive manner. These fungi were once seen as a well definite class of Basidiomycota, but nowadays they are considered an artificial assemblage, because the organisms have independent evolutionary histories forming a polyphyletic group with a vast morphological variety. Despite their diversity, studies with this group in the tropics are incipient, and the phylogenetic relationships of the species from temperate climate remain unknown. Thus, this work aimed to elucidate the phylogenetic relationships of gasteroids fungi from the Geastrales and Phallales orders, with the inclusion of tropical and temperate species, and with these analyses suggest a systematic position of species like Aseroë floriformis and Phallus roseus, as well as to verify if the lignicolous habit can indicate parental relationship in the Geastrum genus. For this, basidiomata were collected at Atlantic rain forest areas, during the rainy season, and the specimen identification followed specific literature for gasteroid fungi. The phylogenetic analyses were performed with Maximum Parsimony and Bayesian Analysis, making use of RPB2 and 28S nuclear genes and atp6 mitochondrial gene. It could be observed on the Phallales dendogram, that Aseroë floriformis did not cluster with A. rubra, and that it has an anterior divergence from all others species of the family Clathraceae used in this analysis, assuming a basal position in the clade. Phallus roseus, which once was recognized as Itajahya, has previous divergence from the group formed by Phallus species. At the Geastrales dendogram, in the group corresponding to Geastrum genus, it could be observed that species with lignicolous habitat clustered in a clade with high support values. So, the results suggest the creation of a new genus to accommodate A. floriformis, and the revalidation of Itajahya, as well as it can be affirmed that the lignicolous habitat on the Geastrum genus in fact indicates parental relationships, and that it has arised only once at the evolutionary history of the genus

Development of a scar marker for Pierce's Disease strains of Xylella fastidiosa

O objetivo deste trabalho foi desenvolver um oligonucleotídeo iniciador para reação em cadeia da polimerase (PCR) específico para as estirpes de Xylella fastidiosa que causam o mal de Pierce (PD) em videira (Vitis vinifera). Amplificações de DNA de 23 diferentes hospedeiros, usando o conjunto de oligonucleotídeos REP1-R (5'-IIIICGICGIATCCIGGC-3') e REP 2 (5'-ICGICTTATCI GGCCTAC-3') utilizando o programa: 94 ºC/2 min; 35 X (94 ºC/1 min, 45 ºC/1 min; 72 ºC/1 min and 30 s) 72 ºC/5 min, produziu um fragmento de 630 pb que diferenciou as estirpes de videiras dos demais. Entretanto, padrões de bandeamento REP não são considerados confiáveis para detecção devido ao par de oligonucleotídeos REP 1 e REP 2 corresponderem a seqüências repetitivas encontradas por todo o genoma bacteriano. Desse modo, o produto amplificado de 630 pb foi eluído do gel de agarose, purificado e seqüenciado. A informação da seqüência nucleotídica foi usada para identificar e sintetizar um oligonucleotídeo específico para o isolado de X. fastidiosa causadora do mal de Pierce denominado Xf-1 (5'-CGGGGGTGTAGGAGGGGTTGT-3'), que foi utilizado juntamente com o oligonucleotídeo REP-2 nas condições 94 ºC/2 min; 35 X (94 ºC/1 min, 62 ºC/1 min; 72 ºC/1 min and 30 s) 72 ºC/10 min. Os DNAs das estirpes de X. fastidiosa de outros hospedeiros [amêndoa (Prumus amygdalus), citros (Citrus spp.), café (Coffea arabica), olmo (Ulmus americana), amora (Morus rubra), carvalho (Quercus rubra), vinca (Catharantus roseus), ameixa (Prunus salicina) e ragweed (Ambrosia artemisiifolia)] e de bactérias Gram negativas e positivas foram submetidos a amplificação com o conjunto de oligonucleotídeos Xf-1/REP 2. Um fragmento, de aproximadamente 350 pb, foi amplificado apenas com o DNA de X. fastidiosa isolada de videira.