Occurrence and expression of β-galactosidase in dextran-producing Leuconostoc species

The occurrence and expression of -galactosidase among various dextran-producing Leuconostoc strains was determined. -Galactosidase was detected from four of twelve Leuconostoc strains tested. -Galactosidase in L. mesenteroides was induced by lactose and was repressed by glucose. Growth curves of L. mesenteroides on lactose indicated extended lag and late growth phases that were shortened when the inoculum was preexposed to lactose.     

Micropropagation and in vitro conservation of wild <Emphasis Type="Italic">Arachis</Emphasis> species

Wild species of Arachis constitute potential sources of novel genes for groundnut improvement programs and some of them are also considered as new agricultural usage. The majority of these species occur in regions under intensive human activity and their areas of distribution are being drastically reduced, thus requiring effective conservation measures. Conservation of Arachis germplasm is usually carried out in seed banks or as live plants. However, seed renewal can be impaired by loss of germinative potential, and plant multiplication under field conditions can be limited by specific soil and environmental requirements or by low seed yield. Therefore, complementary in vitro methodologies represent an important tool for ex situ conservation of Arachis germplasm. In this work, we analyse the state of art of micropropagation and the use of in vitro conservation methodologies for wild relatives of the groundnut.     

Distribution of diurnal primate species in Togo and Bénin

The Dahomey Gap, a strip of forest-savanna mosaic that interrupts the lowland rainforests of West Africa, is supposed to have acted as a natural barrier to the distribution of forest-dwelling mammals. However, few thorough mammal surveys have been conducted in this region. This study intended to gather distributional data and help clarify the distribution limits of diurnal primates occurring within this 'Gap'. Southern Togo and Bénin were surveyed between June and November 2003. The surveys consisted of interviews with hunters and guards from parks and reserves, and walking surveys of forests. As a result, seven diurnal primate species are listed for Togo and Bénin.     

Conservation <Emphasis Type="BoldItalic">in vitro</Emphasis> of rare and threatened ferns—case studies of biodiversity hotspot and island species

The importance of in vitro tools to complement other ex situ methods for saving plants from extinction is more relevant than ever before. More than 50% of the world’s plant species are endemic to the 34 global biodiversity hotspots (GBHs), each holding at least 1,500 endemic plant species. In addition, a large number of small islands hold a number of endemic species on the brink of extinction. Conservation support concentrating more on these hotspots and small islands would significantly reduce the loss of species that is currently occurring. In the majority of these cases, the resources are either locally scarce or difficult to access for in vitro conservation to support other ex situ measures. Most island countries are small, and their geographical position is a stumbling block to initiate active partnerships with other countries when they need to use in vitro tools to rescue plants that produce recalcitrant seeds/spores or propagate only by vegetative means. However, many biodiversity hotspot countries have facilities and expertise, and they concentrate on their own flora for in vitro conservation programmes. For decades, because of the grave threat these plants face, the Conservation Biotechnology Unit, previously known as the Micropropagation Unit, at Royal Botanic Gardens Kew (RBG Kew) has been at the forefront of assisting countries to save their valuable biodiversity through both in situ and ex situ methods. Approaches mentioned here highlight work on recalcitrant ferns from GBHs and small islands. Source materials from recalcitrant species, either spore or seed and in some cases vegetative material, need to be used immediately after collection for tangible results in vitro. This becomes more difficult when only a few plants or small populations are left in the wild. The task becomes harder when available material is small in quantity, and there is greater restriction on the use of available genetic diversity in the wild. This paper highlights the importance of proper collection measures, in vitro culture procedures and cryopreservation and methods for the integrated conservation of threatened ferns from both GBHs and small islands. The importance of international networking to achieve these conservation goals also will be discussed.     

Conservation and change in structural and 5′ flanking sequences of esterase 6 in siblingDrosophila species

Esterase 6 (Est-6/EST6) is the major β-carboxylesterase inD. melanogaster and its siblingsD. simulans andD. mauritiana. It is expressed in several tissues but its major site of expression is the sperm ejaculatory duct of the adult male. Although EST6 activity affects reproductive fitness, there are high levels of electrophoretic and activity polymorphism, at least withinD. melanogaster andD. simulans. Here we present the nucleotide sequences of anEst-6 allele and its flanking regions from each ofD. simulans andD. mauritiana and compare them with the publishedD. melanogaster sequences. As might be expected, replacement sites are significantly less divergent than exon silent sites in all comparisons, suggesting that selection is acting to maintain EST6 structure and function among the three species. Nevertheless, the ratio of the levels of replacement to silent site divergence is still much higher forEst-6 than for seven of ten other genes (including both isozyme-coding loci) for which comparable data have been published for these species. This is consistent with the high levels of EST6 electrophoretic polymorphism withinD. melanogaster andD. simulans and implies that selective constraints against amino acid change are relatively weak for EST6. By contrast, comparisons involving promotor sequences show that the level of divergence in the first 350bp 5′ of the gene is significantly lower than those for four of the six other loci for which comparable data have been published for these species. In particular, there are two perfectly conserved stretches (−1 to −158bp and −219 to −334bp) each over 100bp long included in this 350bp region. Thus the data suggest a relatively low level of selective constraint on the amino acid sequence of EST6 but a relatively high level of constraint on sequences affecting aspects of its expression.     

3,000 species and no end – species richness and community pattern of woodland macrofungi in Mecklenburg-Western Pomerania,Germany

In addition to newly generated and continuously growing datasets in mycological research, existing compilations are of high value to assess the fungi of a whole region. In the present study, a private database with ca. 65,000 entries of macromycetous fruit body observations in Mecklenburg-Western Pomerania, Germany, was analysed. Observed species richness of tree-associated mycorrhizal and saprobic fungi exceeded 3,000 taxa. The total fungal species richness could not be determined with confidence but will possibly exceed 4,000. Distinct species turnover with respect to host trees was observed. However, the rate of community overlap clearly differed between mycorrhizal and saprobic fungi and deciduous and coniferous trees. By separating the data into abundant core species and rare satellite taxa potential indicator species are presented, whose preservation will be beneficial to many other fungi and the entire ecosystems they live in.     

The role of the Weberian Reform in European Rubus research and the taxonomy of locally distributed species – which species should we describe?

After Sudre published his treatment of European Rubi in the early 20th century, Rubus taxonomy in Europe suffered from a scholastic phase and a longer period of stagnation. The so‐called ‘Weberian Reform’ initiated the necessary revival of European batology. It rests on four major pillars: 1) mapping projects over larger areas, 2) evaluation of type material, 3) visits to loci classici, and 4) evaluation of the status of species by means of their distribution areas. Subsequently, it has become widely accepted in European batology that only species with a distribution area over 50 km should be described. Although this pragmatic species concept has been useful in making a continent‐wide overview of brambles, we argue that it is lacking a scientific basis, and should thus be rejected. There are at least four distinctive problems when treating locally distributed brambles: 1) primary hybrids, 2) locally distributed stabilised apomicts, 3) intraspecific variation in species with a larger distribution range, and 4) unstabilised swarms of hybridogenic biotypes and the derivates thereof (mainly in the montane regions). When facing the problems in Rubus systematics, we argue that all independently evolving lineages should be described as species, including apomictic lineages with very small distribution ranges, both from the mountain‐dwelling glandular series and from the lowlands. Neither primary hybrids (which are not stabilised by apomixis), nor biotypes without an independent and coherent distribution area are independently evolving lineages, and should thus not be described as species. We advocate a restrained attitude when describing new species with limited distribution areas.     

Co-variation and indicators of species diversity: Can richness of forest-dwelling species be predicted in northern boreal forests?

Design and establishment of ecologically good networks of conservation areas often requires quick assessments of their biodiversity. Reliable indicators would be useful when doing such assessments. In order to explore the potential indicators for species richness in boreal forests, we studied (1) the co-variation of species richness and composition of species assemblages among beetles, polypores, birds and vascular plants, (2) the relationships between species richness and four boreal forest site types, (3) the relationship between species richness and forest physical structure and (4) the suitability of potential indicator groups within the four taxa to predict the species richness generally. The data show that there are probably not a single taxonomic or forest structural characteristic to be used as a general biodiversity indicator or surrogate for all the species. The correlations in species richness among the four taxa studied were low. However, group-specific indicators were obvious: forest site type was a good surrogate for vascular plant richness, and quantity and quality of dead wood predicted the species richness of polypores. The results support the view that different indicators shall be used for different forest types and taxonomic groups. These indicators should facilitate relatively rapid methods to assess biodiversity patterns at the forest stand level.     

Variation of δ<Superscript>13</Superscript>C of wood and foliage with canopy height differs between evergreen and deciduous species in a temperate forest

We investigated post-photosynthetic fractionation and carbon transfer mechanisms of different plant functional types growing under the same climatic conditions in North-eastern China. The variations in δ¹³C of trunk and branches were compared with leaf δ¹³C at different canopy heights of Pinus koraiensis (evergreen coniferous species), Larix gmelinii (deciduous coniferous species) and Quercus mongolica (deciduous broad-leaved species). Results showed that δ¹³C of leaves increased (became more enriched) with increasing canopy height for both coniferous species (P. koraiensis, L. gmelinii) but not for Q. mongolica (a deciduous broad-leaved species). δ¹³C of both trunk and branches also increased with sampling height for the evergreen conifer P. koraiensis but did not significantly vary for either of the deciduous species (L. gmelinii or Q. mongolica), except a significant increase in branch δ¹³C for L. gmelinii. Similarly, δ¹³C of trunk and branches were strongly correlated with leaf δ¹³C only in the evergreen conifer, P. koraiensis. ¹³C was consistently more enriched in trunk, branches, and roots compared to leaves in all three species. Our findings suggest that, even under the same climatic conditions, different plant functional types may exhibit different carbon transfer mechanisms. This is contrary to the previous hypothesis that different carbon transfer mechanisms operate in forests of different climatic zones, especially in tropical and temperate forests. Particularly, the differences occur predominantly between evergreen and deciduous trees rather than between coniferous and broad-leaved trees. The significant difference in δ¹³C between leaves and wood tissues confirms a previous post-photosynthetic isotope fractionation in temperate forests.     

The evolution of signal–reward correlations in bee- and hummingbird-pollinated species of Salvia

Within-individual variation in floral advertising and reward traits is a feature experienced by pollinators that visit different flowers of the same plant. Pollinators can use advertising traits to gather information about the quality and amount of rewards, leading to the evolution of signal–reward correlations. As long as plants differ in the reliability of their signals and pollinators base their foraging decisions on this information, natural selection should act on within-individual correlations between signals and rewards. Because birds and bees differ in their cognitive capabilities, and use different floral traits as signals, we tested the occurrence of adaptive divergence of the within-individual signal–reward correlations among Salvia species that are pollinated either by bees or by hummingbirds. They are expected to use different floral advertising traits: frontal traits in the case of bees and side traits in the case of hummingbirds. We confirmed this expectation as bee- and hummingbird-pollinated species differed in which specific traits are predominantly associated with nectar reward at the within-individual level. Our findings highlight the adaptive value of within-individual variation and covariation patterns, commonly disregarded as ‘environmental noise’, and are consistent with the hypothesis that pollinator-mediated selection affects the correlation pattern among floral traits.     

Do species evenness and plant density influence the magnitude of selection and complementarity effects in annual plant species mixtures?

Abstract Plant species richness influences primary productivity via mechanisms that (1) favour species with particular traits (selection effect) and (2) promote niche differentiation between species (complementarity). Influences of species evenness, plant density and other properties of plant communities on productivity are poorly defined, but may depend on whether selection or complementarity prevails in species mixtures. We predicted that selection effects are insensitive to species evenness but increase with plant density, and that the converse is true for complementarity. To test predictions, we grew three species of annuals in monocultures and in three‐species mixtures in which evenness of established plants was varied at each of three plant densities in a cultivated field in Texas, USA. Above‐ground biomass was smaller in mixtures than expected from monocultures because of negative ‘complementarity’ and a negative selection effect. Neither selection nor complementarity varied with species evenness, but selection effects increased at the greatest plant density as predicted.     

Survival and reproduction of plant species in the Qinghai–Tibet Plateau

The Qinghai–Tibet Plateau (QTP) is the highest and largest plateau in the world. It covers correspondingly wide geological, topographical, and climatic gradients, and thus hosts greater biodiversity than surrounding lowlands and other high elevation regions. Due to its extreme environmental and biological diversity, the QTP is an ideal region for studying adaptations of plant species under harsh environmental conditions at multiple evolutionary levels. Many recent ecological studies have revealed functions of distinctive morphological features of various plants in the region that improve their reproductive success. Examples include large and showy bracts, hairy inflorescences, and drooping flowers. Numerous other investigations have examined QTP plants' sexual systems, patterns of biomass allocations, and biotic interactions. This paper summarizes recent advances in understanding of morphological adaptations, plant–plant interactions, plant–pollinator interactions, floral color patterns, pollination adaptations, and resource allocation patterns of alpine plants of the QTP. The overall aim is to synthesize current knowledge of the general mechanisms of plant survival and reproduction in this fascinating region.     

Taxonomic composition and species diversity of insect assemblages in grass–shrub cover of peat bogs in Belarus

The species composition and diversity of insect assemblages in the grass–shrub cover has been studied. A total of 374 species from 10 orders have been revealed. Coleoptera, Diptera, Heteroptera, and Auchenorryncha prevailed. Each order was dominated by two to eight species. These species are Cixius similis Kirschbaum, 1868; Neophilaenus lineatus (Linnaeus, 1758); Lepyronia coleoptrata (Linnaeus, 1758) (Auchenorryncha); Lygus pratensis (Linnaeus, 1758); Kleidocerys resedae (Panzer, 1797); Stictopleurus crassicornis (Linnaeus, 1758) (Heteroptera); Lochmaea suturalis (Thomson, 1866); Cyphon padi (Linnaeus, 1758); Plateumaris discolor (Herbst, 1795) (Coleoptera); etc. The assemblages were characterized by low species diversity and distribution of species abundance. The most similar entomocomplexes were those in biotopes dominated by herbs, on the one hand, and dwarf shrubs, on the other. The regression analysis has shown a significant relation between the species richness and diversity of insects and the species composition of plants and their projective cover. The multivariate analysis with various methods (CCA and PCA) demonstrated the influence of these factors on the spatial distribution of certain species and their preferences to particular habitats.     

Dynamics and potential impact of ‘generalist’ phytoseiids in agroecosystems and possibilities for establishment of exotic species

Generalists, i.e. those species which consume a wide variety of foods, including some of plant origin such as pollen, are the dominant members of the phytoseiid mite fauna in some perennial crops. Biological attributes commonly evident in generalist in contrast to specialist phytoseiids include a lower reproductive potential on mite prey, close association with certain plant species, population increases in the absence of mite prey, and intraplant distribution unrelated to that of spider mites. Some studies are reviewed that suggest the ability of certain generalist phytoseiids to maintain tetranychid populations at low densities. Possible biological factors influencing the establishment of exotic generalist phytoseiids are considered. Some of the attributes usually considered important in effective phytoseiid predators may be of minor importance in more stable situations at low population densities.     

Biogeography of seeder and resprouter Erica species in the Cape Floristic Region—Where are the resprouters?

The genus Erica L., with more than 600 species, and a high number of endemics, represents the most remarkable example of floristic diversity in the Cape Floristic Region (CFR). It is largely confined to nutrient-poor, acidic, sandy soils, being one of the most characteristic element of fynbos. The ability to survive fires, resprouting from a lignotuber, is a common trait among Euro-mediterranean Erica species. In contrast, resprouting is fairly uncommon among ericas in the CFR (less than 10%). Most of them are killed by fire, regenerating only but readily by seed germination. An extensive survey on the resprouting ability of South African Erica species was carried out and the pattern of geographical distribution of resprouters and seeders in the CFR was determined. The geographical distribution of these two regeneration classes was related to a climatic gradient of seasonality along the CFR. A pattern of higher proportions of resprouter species towards the mediterranean, strongly seasonal northwestern CFR and the non-seasonal eastern CFR and summer rainfall area outside the CFR was identified. The number of resprouter species reaches a maximum in the eastern CFR and is lower in the southwestern CFR despite the overall higher concentration of species in this subregion. Summer drought strongly influences the effectiveness of post-fire regeneration and growth (i.e. new recruits plus survivors) of Erica species, and is the major selective force accounting for the pattern of distribution of seeders and resprouters in the CFR. A mild mediterranean climate with reliable autumn-winter rains and a short summer drought, typical of the mountain areas of the southwestern CFR, favours recruitment of seeders but hampers recruitment of resprouters. Resprouter species persist and become dominant under harsh conditions for recruitment (severe summer drought) and would coexist with seeders under situations of no summer stress. Diversification is associated with seeder lineages. Hence, number of seeder species will be higher than number of resprouters, especially in the southwestern CFR, where favourable conditions for recruitment allow a massive concentration of seeder species, many of them narrow endemics.     

The relative of species pools in determining plant species richness: an alternative explanation of species coexistence?

Explanations of the pattern of species have traditionally relied on small-scale, local processes occurring in ecological time. Differences in species richness have associated with different mechanisms avoiding competition, such as spatiotemporal heterogeneity (weaker competitors may find a more favourable place or time) or environmental stress (competition is assumed to be less intensive under difficult conditions). More recently, large-scale process have been taken into account, raising such questions as: which plant species may potentially grow in a certain community? Are evolutionary processes and species dispersal responsible for the differences between communities? The species-pool theory attempts to answer these general questions, and information about species pools is needed for the design of experiments where the number of species in a community is manipulated.     

Spatial–temporal patterns of flowering asynchrony and pollinator fidelity in hybridizing species of Narcissus

Speciation requires the evolution of reproductive barriers to achieve isolation between species. In this paper, we examine the role of two major pre-zygotic barriers in reducing the chance of F₁ hybrid formation between two pairs of Narcissus species. Field experiments were performed over 5?years in eight natural populations to determine whether flowering phenology and pollinator fidelity could act as reproductive isolation barriers in Narcissus. Our results show that reproductive isolation due to flowering phenology is highly variable and asymmetric. In some populations, pollinator fidelity was so strong that the quantification of reproductive isolation was complete and a strong negative correlation was found between the strength of this barrier and the abundance of hybrids. Nevertheless, the degree of pollinator fidelity was quite variable among populations indicating that reproductive isolation varies geographically but very consistent across years indicating that plant-pollinator interactions are well established. In fact, the finding that hybrid formation between these species occurs only in sites where pollinator fidelity is incomplete suggests that hybrid formation also varies geographically and that divergent evolutionary outcomes may occur in different sympatric populations of Narcissus.