نتایج جستجو برای: maidenhair fern
تعداد نتایج: 2574 فیلتر نتایج به سال:
An affine transformation on the plane is a mapping T that preserves collinearity and ratios of distances: given two points A and B, if C is the middle of the segment [A,B] then T (C) is the middle of the segment [T (A), T (B)]. Translations, contractions, expansions, reflections, rotations, are all particular cases of affine transformations. In general, an affine transformation T maps a point (...
Pteridophytes are not as well characterized at the molecular and biochemical level as some higher plants. However, to aid conservation efforts (4), there is growing interest in understanding the population biology of many fern species that are under threat. DNAbased studies offer excellent tools for such work, but are hampered in ferns by difficulties in obtaining good-quality DNA from sufficie...
Mechanisms of uptake of rare earth elements (REEs) were investigated, particularly those by REE accumulator species (autumn fern). Rare earth elements are practically insoluble under natural conditions, suggesting some unknown mechanism in REE accumulator species. In the present investigation, two notable phenomena were observed. (I) Concerning the ionic-radius dependence of REE uptake by leave...
This study reports the analyses of the rhizospheric microbiome of the terrestrial mangrove fern Acrostichum aureum Linn. from the Indian Sunderbans. Samples were collected using standard protocols and 16S rRNA gene V3-V4 region amplicon sequencing was performed to identify the microbial communities prevalent in the rhizosphere. A total of 1,931,252 quality checked reads were assembled into 204,...
The name Doronicum thibetanum Cavill. has been inadvertently applied in herbarium labels to designate a species distributed in central China (provinces of Gansu and Sichuan). However, the study of the type specimen reveals that it is actually a species of Aster. The central Asian species of Doronicum has no available name and is thus here described as D. cavillieri Álv. Fern. & Nieto Fel. This ...
Ferns are the only major lineage of vascular plants not represented by a sequenced nuclear genome. This lack of genome sequence information significantly impedes our ability to understand and reconstruct genome evolution not only in ferns, but across all land plants. Azolla and Ceratopteris are ideal and complementary candidates to be the first ferns to have their nuclear genomes sequenced. The...
Chronic ingestion of bracken fern (Pteridium spp.) by cattle produces upper alimentary tract and urinary bladder tumours causing a syndrome called bovine enzootic haematuria (BEH). Previous studies demonstrated ptaquiloside-DNA adducts and mutations in the h-ras gene in ileal epithelial cells of bracken fern-fed calves. Systematic inspection of the bladder mucosa of grazing cattle (n=126) from ...
The maintenance of genetic diversity and stochastic losses of diversity during periods of small population size have become major points of concern in conservation biology. However, empirical research on random evolutionary processes in natural plant populations is still scarce and is reviewed here in comparison to our case study on Dryopteris cristata. Detailed recent population histories of t...
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