We used space-for-time substitution to obtain a directed successional sequence for subalpine meadow vegetation in the Swiss National Park. Since human impacts (e.g., domestic animal grazing) ceased in 1914, the successional processes documented are assumed to be autogenic in nature. The data consist of 59 permanent plots spanning almost 90 years, and include many spatial replications. An initial inspection of the individual time series revealed the existence of a variety of response patterns, which are described in the literature as representing different successional types. However, a closer inspection suggested that many of these series can be superimposed, as they are part of a much longer deterministic series. Linking the individual time series proved to be challenging. A heuristic approach produced results that differed depending on initial starting conditions. We therefore derived a deterministic algorithm to produce a unique solution. The resulting sequence largely confirmed the heuristic interpretation, suggesting a trend from early successional (post-grazing) grassland to pine invasion spanning about 400 years. This timespan is valid only for the climatic conditions near the treeline, and for plant species specific to the study site. Our results suggest that the various species temporal response models described in the literature may be artifactual, representing portions of underlying Gaussian responses. The data also indicate that species assemblages may persist for several decades with only minor fluctuations, only to change suddenly for no apparent reason.
Authors:M. F. Vianna, S. Pelizza, M. L. Russo, S. Rodriguez, and A. C. Scorsetti
The diversity of fungal endophytes is poorly known and particularly in the case of Nicotiana tabacum, the literature is limited. The present study assessed and compared the diversity and distribution of endophytic fungi between different organs of tobacco plants. We calculated the relative frequency and rates of colonisation and of isolation of endophytic fungi in roots, stems and leaves, as well as the Shannon–Wiener and Simpson diversity indexes. Similarities between assemblages from the studied organs were also analysed. A total of 1588 endophytic fungal strains assigned to 31 morphospecies were isolated. The highest diversity of endophytes was found in leaves, being Fusarium graminearum and Alternaria botrytis the most common fungal species. This study provides information on the distribution of fungal endophytes inhabiting leaves, stems, and roots of N. tabacum and thus can serve as a starting point for increasing our comprehension on the interactions in which these fungi are involved.
Yuncker is recorded as a novum on the Palni Hills (India). The parasite occurs in great quantities along the edge of roads, agricultural fields (mostly coffee plantations) and along the bank of streams. The species parasitized every herbaceous plant which came into contact with it. In the examined herbaria every specimen that was collected from the hills under the name of
Lam. was reidentified as
. In addition, despite of the systematic field research there was not found any
specimen on the Palni Hills. In this study, several illustrations of
are collected and displayed, furthermore the international literature of the morphology and taxonomy of the species are reviewed.
191 species of hepatics are reported from the Dominican Republic, among these 138 first records; a considerable number of species (34) is new to the West Indies as a whole, eight species and one variety have been known in the West Indies only from the Lesser Antilles, 77 are new to Hispaniola, and 18 new to the Dominican Republic. Notes on ecology, altitudinal and geographical range are provided. 55 additional literature reports are included thus a preliminary first checklist of the hepatics of the Dominican Republic is provided. 246 species of hepatics and Anthocerotae are now known to occur in the Dominican Republic.
Pócs is described as new to science. One new combination,
(Hampe ex Lehm.) Váňa et Schäfer-Verwimp, is made.
The paper revises and re-discusses the literature dealing with the phytosociology of the Spiraea rock heath communities based on relevés collected in North Hungary (Northern Hungarian Mountain Range) and South Hungary (Mecsek and Villány Mts). The comparative analyses confirmed the separation of the formerly described two associations and added one new subassociation to each. These are Waldsteinio-Spiraeetum mediae filipenduletosum and Helleboro odori-Spiraeetum scilletosum. Differences between stands along the three possible ecological gradients (southwest-northeast, north-facing vs. south-facing and vertical) were also analysed. An obvious continentality trend is identified along a southwest-northeast gradient and obvious ecological differences are detected between the south-facing and north-facing Spiraea stands. In contrast, no ecological trend is recognisable along a vertical gradient.
Authors:R. Prasanna, A. Sood, A. Suresh, S. Nayak, and B. Kaushik
A wide variety of pigments, like chlorophyll, carotenoids and phycobiliproteins, which exhibit colours ranging from green, yellow, brown to red are present in algae. Increasing awareness of harmful effects of synthetic dyes and inclination of society towards the usage of natural products, such as plant / microbial based colours in food and cosmetics, has led to the exploitation of microalgae as a source of natural colours. Algal pigments have great commercial value as natural colorants in nutraceutical, cosmetics and pharmaceutical industry, besides their health benefits.
capsules are now commonly prescribed health foods for improving vitality and longevity of human beings. This review describes the distribution, structure of these pigments in algae, with emphasis on specific techniques for extraction and purification, along with different methods of biomass production and commercially feasible techniques documented in literature. An overview of the industrial applications of these natural colouring agents in diagnostics, food and cosmetics industry is also provided.
Important predictors of the species richness of vascular plants and epiphytic lichens on Populus spp in the Canadian aspen parkland were determined. Plants and lichens were sampled on three scales within 100 treed patches within an area of less than 4 km2 (patch-scale and two within-patch scales). Small-scale species richness within patches was positively related to the number of species in the surrounding patch and a few measured environmental variables. This suggests that, at this scale, the species richness of these communities is limited by the availability of species in addition to local environmental conditions and species habitat preferences. For plant species richness, environmental variables that were related to light availability were most important, whereas for epiphytic lichens, variables that were related to moisture availability on trees were most important. This study adds to a growing body of literature showing that both small-scale and larger-scale processes affect species richness within communities.
Mature barley (Hordeum vulgare cv. Zafer-160) embryos were cultured on callus induction medium (MS+ 4 mg l−1 Dicamba) for 30 days and embryogenic calli were transferred onto regeneration medium (MS+ 0.5 mg l−1 trans-zeatin riboside). Callus induction percentage was 67.2%; embryogenic callus induction percentage was 42.3% and their regeneration percentage was 63.8%. Retrotransposon movements and methylation alterations in 15-day-old, 30-day-old calli and 4-day-old barley seedling (control) were investigated with Inter-Retrotransposon Amplified Polymorphism (IRAP) and Methylation-Sensitive Restriction Fingerprinting (MSRF), respectively. IRAP patterns were quite monomorphic however MSRF indicated increase in cytosine methylation during callus formation. Changes in retroelement movements and methylation alterations were evaluated and discussed in the light of literature.
Authors:A. Wiater, J. Szczodrak, and M. Pleszczyńska
The strain Streptococcus sobrinus CCUG 21020 was found to produce water-insoluble and adhesive mutan. The factors influencing both stages of the mutan production, i.e. streptococcal cultures and glucan synthesis in post-culture supernatants were standardized. The application of optimized process parameters for mutan production on a larger scale made it possible to obtain approximately 2.2 g of water-insoluble glucan per 1 l of culture supernate - this productivity was higher than the best reported in the literature. It was shown that some of the tested beet sugars might be successfully utilized as substitutes for pure sucrose in the process of mutan synthesis. Nuclear magnetic resonance analyses confirmed that the insoluble biopolymer synthesized by a mixture of crude glucosyltransferases was a mixed-linkage (1?3), (1?6)-a?-D-glucan (the so-called mutan) with a greater proportion of 1,3 to 1,6 linkages.