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Background Diabetic nephropathy (DN) is a serious consequence of diabetes mellitus (DM), and it is linked to higher morbidity and mortality in diabetic patients. The quest for cheap therapeutic strategy with lesser side effects remains a major health concern. However, Dryopteris dilatata is a commonly found flavonoid-rich plant with plethora of therapeutic potentials. This study investigated the effect of methanol extract of D. dilatata (MEDd) on streptozotocin-induced diabetic nephropathy in male Wistar rat. Methods Animals were randomly selected into five groups ( n  = 5) and were treated as follows; group 1 received distilled water (10 mL/kg), group 2 received only STZ (60 mg/kg), groups 3 and 4 received STZ then 400 and 800 mg/kg of MEDd, respectively, while group 5 received STZ then pioglitazone (10 mg/kg). Following 14 days of treatment, animals were euthanized, and blood as well as pancreas and kidney tissues were collected for further studies. Results Our results revealed that MEDd significantly reduced STZ-induced hyperglycemia in diabetic rats. Markers of oxidative injury (MDA, nitrite, and GSH) were also significantly ameliorated in the pancreas and kidney of the diabetic rats following treatment with MEDd. However, renal function markers (creatinine and urea) were significantly attenuated with marked decreased in organ weight in the diabetic rats after treatment with MEDd. Also, serum insulin and corticosterone levels were restored following MEDd treatment. Conclusion Methanol extract of D. dilatata demonstrated anti-diabetogenic and reno-protective potential by enhancing in vivo reno-pancreatic antioxidant defense system.

Wet N deposition comprises oxidised (nitrate) and reduced (ammonium) N forms in proportions that vary spatially with source and topography. Field evidence of long-term N form effects on seminatural ecosystems and how these are modified by phosphorus and potassium availability are lacking. This study describes cover changes for some key peatland species and litter chemistry from Sphagnum capillifolium, Calluna and Eriophorum vaginatum, and peat in response to 9 years of N treatment. Ammonium and nitrate as NH₄Cl or NaNO₃ were provided to replicate plots in rainwater spray at +8 (low) or +56 (high) kg N ha⁻¹ year, with and without PK via an automated system coupled to site meteorological conditions. Reduced N caused greater N accumulation in all key species than oxidised N, especially at higher doses, but cover declined more, though not significantly so, with oxidised than reduced N at the high N dose. Overall the detrimental effects of high N on Sphagnum and Calluna cover were significant but small. By comparison PK inclusion with 56 kg N ha⁻¹ year as oxidised N, not reduced N, had devastating effects on cover, causing both S. capillifolium and Calluna to decrease 3–5-fold, facilitating invasion and expansion of nitrophiles, non-characteristic bog plants e.g. Epilobium angustifolium, Epilobium palustre, Juncus effusus, Digitalis purpurea and Dryopteris dilatata. N form appears to be significant for peatlands because of its effects on pH. The significance of changes in plant cover for peat chemistry and decomposition for biogeochemistry is discussed.

We were interested in whether the contrasting regional distribution patterns of three congeneric, frequently co-occurring fern species (Dryopteris carthusiana, D. dilatata and D. expansa) could be explained by differential biomass allocation strategies and different phenotypic plasticities to light availability. The morphology and habitat preference of these ferns are known to be very similar, but in Estonia, their frequencies of occurrence differ sharply--Dryopteris carthusiana is common, D. expansa grows in scattered localities, and D. dilatata is rare. We grew the species under different levels of illumination (100, 50, 25 and 10% of full daylight) in an experimental garden to compare their autecological responses to shading. After one growing season there were clear interspecific differences in total plant biomass accumulation--D. carthusiana > D. expansa > D. dilatata--indicating the possible competitive inferiority of the latter at the young sporophyte stage. D. expansa was the least shade-tolerant, with biomass decreasing sharply under less than 50% illumination; D. dilatata was the most shade-tolerant, with similar growth at all illumination levels. In relative biomass allocation patterns, the most notable differences among species were in the relative shares of biomass stored in rhizomes. In D. carthusiana and D. expansa this share was nearly constant and independent of the illumination conditions. D. dilatata allocated very little biomass into rhizome in deep shade, but was able to increase this share more than twofold in 50% light. Dryopteris dilatata was clearly shown to be morphologically the most plastic of the three. In four traits--rhizome mass, frond: below-ground biomass ratio, stipe length and specific leaf area--its degree of ontogenetic plasticity to light was significantly higher than that of D. expansa and D. carthusiana. While the general performance (biomass production) of species in the experiment coincided with that observed in nature, the results of plasticity estimation were somewhat surprising--it is difficult to explain the inferior performance of a species (D. dilatata) through high morphological plasticity. Probably, the species is rare either because of certain climatic restrictions, or because it is presently expanding its distribution and is in the phase of invading Estonian understory communities.

We studied seasonal changes in the understorey biomass of an oak-hornbeam forest association Galiosylvatici-Carpinetum betuli. Samples were collected weekly during the most dynamic period of herbaceous layer development (April-May 2010), and every two weeks for the remainder of the growing season (June-October). Samples were collected from 10 randomly selected localities of 0.36 m2 within the plant community. The plants harvested were separated by species, then oven-dried and weighed. There were statistically significant differences in aboveground understorey biomass during the time between harvests. For example, the lowest plant biomass (produced in 2010 and previous years) was found on April 3rd (37.2 kg/ha), whereas the two highest were on May 1st (308.1 kg/ha) and June 12th (337.6 kg/ha). The lowest biomass of plants produced in 2010 was on April 3rd (13.0 kg/ha) and the highest was on May 1st (259.8 kg/ha). When biomass of particular herbaceous plant species were analyzed, there was no one clearly dominant species. For example, from March 20th to May 22nd the biomass of Ficaria verna was the highest at ca. 36% of the total herbaceous layer plant biomass (range: 14.5-51.0%). During the next harvesting period (June-October), there were a few dominant herbaceous plant species, e.g. Geranium robertianum, Stachys sylvatica, Impatiens parviflora, Dryopteris dilatata, Dryopteris carthusiana, Dryopteris filix-mas, and Maianthemum bifolium.

Despite the large number of comparative studies on species with different distribution and abundance, no clear general pattern of attributes explaining species' rarity has yet been found. The relationship between different life-history traits of a species and abundance tend to be conditional and context dependent. We were interested in whether the local relative population density of three fern species in Estonia is related to post-emergence growth of their young sporophytes, i.e., that the locally abundant species, D. carthusiana, has the highest vegetative growth in its first growth periods and the two less abundant species, D. dilatata and D. expansa, have lower. We were also interested in differences between generative traits of young sporophytes of three species, specifically in the number of spores. We grew the species in a garden experiment for two vegetation periods, 2004–2005, until the first sporulation. The relative population density of the three Dryopteris species was related to the relative post-emergence growth of the species. The most abundant species D. carthusiana, exhibited the highest values of vegetative growth parameters in the first growth period. The less abundant D. dilatata and D. expansa both had shorter fronds, shorter intensive growth periods and lower leaf elongation rates. Dryopteris dilatata had a different vegetative growth strategy compared to the other two species; it differed in timing of intensive growth of frond length and increase of frond number and had the lowest values of generative parameters among the three species.

The research plots were established in damaged - by pollutants, fungi and bark beetle, and parallel damaged (control) spruce geobiocoenoses pertaining to company Forest of Spisská Nová Ves city Ltd. (locality Murán - 1,100 m asl, group of forest types Fageta abietino-piceosa, Skeli-Humic Podzol; locality Hliníky - 950 m asl, group of forest types Abieti-Fageta inferiora, very acid Dystric Cambisol). The higher mean shoot length, weight and energy content were found in populations of Dryopteris dilatata species growing on locality Hliniky and in damaged spruce stand on locality Murán. On the other hand the higher ash content was in shoots sampled on non-damaged plots. Content of risk elements ranged in following intervals (mg kg^sup -1^ of dry matter): Al (88.3-225.0), Pb (2.184-3.340), Ni (0.873-4.379), Cr (0.050-0.220), Cd (0.571-1.918), Hg (0.0312-0.0423). Limit value Hg (0.02 mg kg^sup -1^) was exceeded on all studied plots, while the normal value of Al (about 200 mg kg^sup -1^) only in case of population growing in damaged stand on locality Hliniky. [PUBLICATION ABSTRACT]

The relation of lenght, leaf area, phytomass and content of energy in selected herb species to different permanent ecological conditions of the 5 natural spruce ecosystems in the Bielovodska dolina valley (Vysoke Tatry Mts) was studied. The canopy of spruce stands and light conditions of phytocoenoses were dependent on content of skeleton and/or depth of podzolic soils. The differences in permanent ecological conditions were the most remarkably reflected in changes of energy content and length of the studied herb species individuals. Significant changes in energy content were primarily found in Oxalis acetosella (in 90% of cases), Dryopteris dilatata (70%) and Luzula sylvatica (70%), in the case of length in Vaccinium myrtillus (80%) and Homogyne alpina (50%). Among the life forms of the plant species, hemicryptophytes were dominant (67-73%), less abundant were geophytes (12-22%) and chamephytes (10-18%).

The new Dutch forest monitoring network is a policy-guided, multiple-use, GIS-oriented forest monitoring network. It is designed to provide the Dutch government, on a cyclic 8-year basis, with actual information about Dutch forests. Variables that reflect the information needs of policy makers and interest groups were selected by means of interviews and workshops. High-ranking variables are: wood stock, ownership, stand age, management status, biodiversity, carbon stock, and recreational use. These and other variables are being measured in 3622 forest sites, selected according to an unaligned systematic sampling design. The data are stored in an ORACLE data base, made accessible through the internet. The Dutch forest area approximates a total of 360 000 ha; 46% is owned by private owners and organisations for nature conservation. Coniferous forests dominate (60%). Most forests were planted in 1940-1980. The total above ground volume of living trunk wood amounts to 56.3 million m3. The most common tree species are Quercus robur, Pinus sylvestris, and Betula pendula, the most common shrubs are Sorbus aucuparia, Prunus serotina, and Rhamnus frangula; while the most common other plant species are Deschampsia flexuosa, Rubus fruticosus s.l., and Dryopteris dilatata.

The understories of 71 small stands strongly dominated by hemlock (Tsuga canadensis [L.] Carr.) were sampled in a transect from northern Wisconsin to Nova Scotia. Stands selected for sampling were at least 100 yr old and had homogeneous overstories composed of at least 75% hemlock. Stand area varied from 0.04 to 2.4 ha, with most stands between 0.2 and 0.8 ha. All stands were local areas of strong hemlock dominance within a much larger mixed forest. The hemlock understories, as a group, are not a distinctive community type with respect to composition (vascular plants). There are no species relatively abundant in the hemlock stands that are not also abundant in other types of mesophytic forest. Presence and coverage of species vary greatly from stand to stand, even on similar soils and topography, suggesting that community organization is haphazard. However, a few species are almost ubiquitous (Tsuga canadensis, Acer rubrum, Maianthemum canadense, Dryopteris austriaca), and others consistently attain high coverage when present (e.g., Taxus canadensis, Oxalis montana). Also, the mean association (Cole's index) between pairs of common species (50-69% presence) significantly exceeds the mean association in stands not strongly dominated by a single overstory species (i.e., mixed hardwood forests with varying proportions of sugar maple and basswood in the overstory). Half of the 66 understory species that are at least moderately common in non-hemlock forest throughout the study area are rare or absent under hemlock in some parts of the transect, yet common in other parts. Regional differences in composition, however, are not discrete. Regional differences in understory composition are poorly correlated with regional differences in the potential hemlock forest flora (i.e., plants observed growing in hemlock forests). Community transitions also correspond poorly to certain climatic differences between regions, such as the length of the freeze-free period.

Question: Do different competitive abilities of three fern species explain their different regional abundances? Location: Estonia, Europe. Methods: The factorial pot experiment, in which single individuals of three fern species were grown in natural soil with 0, 2, 4, and 8 neighbouring individuals of Deschampsia flexuosa. Results: The response patterns of different biomass fractions and morphological parameters of fern species were similar to each other. The diploid D. expansa was the most vulnerable to competition, while tetraploid D. carthusiana and D. dilatata were more tolerant. D. carthusiana allocated relatively more to below-ground parts than the other two species and allocation to roots increased when neighbour density increased. For D. expansa and D. dilatata, allocation to below-ground parts decreased at high neighbour density, while in D. dilatata also the relative length of the stipe increased. Thus, the response of D. carthusiana corresponds to a ‘persistence type’ and that of D. dilatata to a ‘foraging type’. Conclusions: Lower vulnerability of D. carthusiana to competition, compared to D. expansa, may explain the higher regional and local abundance of the former. The rarity of D. dilatata in Estonia, however, could rather be explained by the impact of climatic factors, since this species is near its northeastern distribution limit in Estonia. Nomenclature: Fraser-Jenkins (1993).