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Botanical changes were examined on a ten-year-old semi-natural grassland established using mixtures with high species diversity. The mixtures contained seventeen wild flowers of natural origin together with two leguminous and seven grass species or varieties. Three different mixtures were arranged in three replications. The grassland management system was non-intensive (without nutrient supply or irrigation). A survey involving cover assessment revealed nine residual species from among the twenty-six originally sown. The main question addressed in the study was whether there was any connection between the ecological properties of the habitat and the ecological needs of the residual species and it was concluded that all the residual species had similar temperature, water balance and soil requirements. It could be seen that the present plant association gave a good reflection of the results of soil analysis. This suggests that soil analysis should be carried out before sowing new species-rich grasslands in order to compile a mixture suited to the nature of the habitat.
Endophytic fungi of three tissues (petiole, bark and leaf) of Alstonia scholaris were assessed. A total number of 1,152 endophytic fungi were isolated from 1,002 different plant segments of seven different localities of Paschim Medinipur, West Bengal, India. The isolated fungi belong to nineteen genera, including four unidentified fungi and yeast. Colletotrichum sp. (20.39%) and Sordaria sp. (29.68%) were most commonly isolated from this plant. Hyalopus sp., Fusarium sp. and Curvularia sp. were also isolated. The colonization frequency of endophytic fungi is much higher in leaves (44.66%) in comparison to petioles (32.16%) and barks (23.17%). The study provided evidence for tissue specificity of endophytic fungi. The endophytic fungal species diversity was higher in plant segments collected from Gopegarh and Khoirullahchak, while diversity was the lowest in Rice mill area. Screenings of antimicrobial activity of these isolated endophytic fungi were done. Eight endophytic fungi showed antimicrobial activity. Among them Curvularia sp., Aspergillus sp. and one unidentified fungus showed maximum activity against test pathogens.
Lake Hévíz is the largest natural warm water lake of Europe. The curative mud of the lake comprises volcanic and marsh components although their species composition is hardly known yet. The aim of the present study was to gain information about the distribution and species diversity of bacterial communities inhabiting the sediment of Lake Hévíz using cultivation-based and molecular cloning methods. Samples from two depths and locations were taken in 2004 and 2007. Representatives of the altogether 255 bacterial isolates were affiliated with the phyla Firmicutes, Actinobacteria, Proteobacteria and Bacteroidetes. The most abundant groups belonged to the genus Bacillus (Firmicutes). Many of Lake Hévíz isolates showed the highest sequence similarity to bacteria known to be plant associated or members of normal human microbiota as well as participating in decomposition of highly resistant organic materials. In the three clone libraries, phylotypes belonging to altogether different phyla (Firmicutes, Actinobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria, Chlorobi, Chloroflexi, Deferribacteres, Nitrospirae, Spirochaetes and Verrucomicrobia) were revealed from which members of Gammaproteobacteria and Cyanobacteria proved to be the most abundant. Regardless of the sampling times and methodology used, high spatial heterogeneities of bacterial community structures were characteristic of the sediment of Lake Hévíz.
Seasonal changes of nitrogen metabolites and Na + /K + ratio were detected in some wild species inhabiting the western desert of Egypt. Seasons, species and their interactions were important factors affecting the total free amino acids and soluble proteins at Dakhla oasis; however, species diversity is more effective variable in regulating such metabolites at Kharga region. Such plants may respond to their environment either by increasing their water binding molecules or by preventing the formation of amino acids into proteins. Some halophytes and xerophytes may adjust osmotically to stress by the contribution of nitrogen metabolites. On the other hand, Zygophyllum coccineum , the succulent plant, may adapt to environmental conditions through the accumulation of free amino acids. The correlation analysis between Na + /K + ratio with free amino acids, soluble proteins and water content in Balanites aegyptiaca, Salsola imbericata, Tamarix aphylla, Trichodesma africanum and Z. coccineum (Kharga) indicated such changes in ionic fraction or accumulating soluble organic compounds that presumably were osmotically active and contribute to osmotic adjustment. Positive correlation was also found between chlorophyll content with ionic and nitrogen metabolites. It is likely to suggest that Acacia nilotica, Suaeda monoica and Z. coccineum at Dakhla may have changed their soluble proteins or ionic ratio as a consequence of chlorophyll response to stress, while S. imbericata and T. aphylla may control cellular protein contents. On the other hand, the interaction of both nitrogen metabolites and ionic fraction may play an important role of osmoregulation in S. imbericata, Citrullus colocynthis and Z. coccineum at Kharga region.
Eight Hymenopteran parasitoids: Itoplectis alternans (Grav.), Itoplectis maculator (F.), Pimpla spuria Grav., Diadegma apostata (Grav.), D. longicaudata Horst., D. tenuipes (Thoms.), D. holopyga (Thoms.) and Dibrachys cavus (Walk.), and one hyperparasitoid Gelis areator (Panz.) have been reared from the larvae and pupae of the grape moth Lobesia botrana (Denis et Schiffermüller), collected between 1996 and 2003 in two wineyards of southern Romania. Nine host-parasitoid relationships have been recorded, from which seven are new for Romania and the other two new to science. The role played by these parasitoids in the regulation of the host populations is 12.3%. Diadegma longicaudata Horst. is the most important member of this parasitoid complex with a parasitizing ratio of 7.75%. The parasitism of hibernating stages is more important than the summer ones, both in percentage (24.2/8.94%), and in species diversity (6/1). The small number of species and the low values of aestival and hibernal parasitizing are the effect of intensive chemical treatments in these vineyards.
This study identifies the long lasting impacts of former cultivation on soils, seed banks and above-ground vegetation of limestone grasslands. We compared the resilience of three crop fields cultivated in the 19th century and abandoned (Abandoned Fields) with three grasslands which have never been cultivated (Old Grasslands). Grasslands were located in the Nature reserve of Grand-Pierre and Vitain valleys in France. Sites were identified using historical sources. Chemical and physical soil properties, above-ground vegetation and soil seed bank (0–10 cm and 10–20 cm) were studied. Data were analysed using a multivariate and univariate analyses to detect the effects/impacts of ancient cultivation. Our results clearly show that soil properties (e.g., calcium, carbonate, clay contents), above-ground vegetation (species diversity, moss and lichen cover) and seed bank (floristic composition, species-richness and diversity) are still impacted more than one century after their abandonment. Species richness of both above ground vegetation and seed bank are higher in old grasslands than in formerly cultivated fields. In the seed bank of the formerly cultivated soils we also found the presence of a very rare arable weed species (Althaea hirsuta) which has not been inventoried for a long time in the above-ground vegetation of the nature reserve. The resilience of formerly cultivated limestone grasslands might be influenced by the present management regime (site effect). Nevertheless, the resilience period of limestone grasslands is very long-more than one century-and return to an initial state might be difficult or impossible to reach.
Abstract
The present work aimed to study the yeast communities of whole crop corn silages (CS) that were previously contaminated with aflatoxin-producing Aspergillus flavus (CSCA). In addition, the effect of lactic acid bacterium (LAB) inoculation on the aflatoxin B1 (AFB1) content, genotoxicity, yeast load, and diversity of yeast communities were also investigated. In A. flavus contaminated silages, after two months, the AFB1 content was 40% lower with LAB inoculation, also a lower level of genotoxicity was determined. The number of yeasts cultured from the initial mixture of chopped whole crop corn was 4.8 × 107 CFU g−1 wet mass, while only 2.4 × 106 CFU g−1 from the CSCA and 7.1 × 105 CFU g−1 from the LAB-inoculated CSCA could be cultured. Based on 144 randomly isolated strains, the yeast community of the initial mixture consisted of 8 species. In contrast, the yeast community of CSCA consisted only of 4 species determined by 132 randomly selected isolates. LAB-inoculated CSCA consisted also of 4 species based on 158 randomly isolated strains. Saccharomyces cerevisiae and Pichia kudriavzevii proved to be predominant in the CSCA, while S. cerevisiae and Meyerozyma guilliermondii were the most abundant in the LAB-inoculated CSCA. The species richness was also confirmed by alpha diversity values (1.827, 1.188, and 1.123 as Shannon's indices for CS, CSCA, and LAB-inoculated CSCA, respectively). In response to LAB inoculation, the species diversity decreased considerably.
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