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PubMedDate not supplied

[Lectins of Dryopteris Adans fern species].

Lectin activity of three ferns species (Dryopteris bushiana Fom., D. laeta (Kom.) C. Chr, D. pseudomas (Wollaston) Holub et Pouzar) has been studied. We used hemagglutination reaction albumin and globulin fractions of fronds and rhizomes extracts with rat erythrocytes. The frond extract of D. pseudomas have shown higher activity as compared with other extracts. The lectin activity of D. laeta leaves was absent. The rhizomes of all three fern species could be characterized as high activity. Based on lectin activity the species were placed as follows order: D. buschiana > D. pseudomas > D. laeta. The dependence with lectin activity and elements (Mn, Fe, Cu, Ni, Zn, Pb, Rb, Sr) content were not found.

Animals↗

PubMed2000

SEM studies on vessels in ferns. 17. Psilotaceae.

Perforation plates are reported in aerial and subaerial axes of Psilotum nudum and in aerial axes of Tmesipteris obliqua. In Psilotum, both perforations lacking pit membranes and perforations with pit membrane remnants were observed. Perforation plates in Psilotum may consist wholly of one type or the other. In Tmespteris, perforations have threadlike pit membranes or consist of porose pit membranes. Wide perforations alternating with narrow pits, a conformation observed in various ferns, were observed in Psilotum (subaerial axes). In Psilotum, perforations are more common in metaxylem than in protoxylem; perforations in protoxylem consist of primary wall areas containing small circular porosities or relatively large circular to oval perforations. There are no modifications in the secondary wall framework of protoxylem or metaxylem in Psilotum or Tmesipteris that would permit one to distinguish presence of perforations or perforation plates with light microscopy, and scanning electron microscopy (SEM) is required for demonstration of porose walls or perforations. The tracheary elements of the Psilotaceae studied have no features not also observed in other ferns with SEM.

Journal Article↗

PubMed2001

Distribution and dynamics of two ferns: Dennstaedtia punctilobula (Dennstaedtiaceae) and Thelypteris noveboracensis (Thelypteridaceae) in a Northeast mixed hardwoods-hemlock forest.

Dennstaedtia punctilobula and Thelypteris noveboracensis are two native species that often arrest forest succession and reduce understory diversity. As part of a project to examine the feedback between forest understory and canopy dynamics, we studied the patterns of distribution and dynamics of these two fern species in an oak-transition hardwoods-hemlock forest. Dennstaedtia was least abundant under shade-tolerant tree species and most abundant in small (1-2 trees) canopy gaps, but did not show any distinct patterns across the sampled moisture regime. The light response was verified using light manipulation experiments and examination of plant size-abundance patterns across light environments. Thelypteris tended to be most prevalent under maple canopies and appeared to be more sensitive to soil moisture regime being restricted to more mesic sites than Dennstaedtia. Seasonal and year-to-year changes in abundance of established clones of both fern species were small, suggesting that once established, both species can maintain a strong hold on a site. Further work on the niche requirements of the two species is warranted, but any event that maintains or promotes canopy openness (tree death by disease or windthrow, forest harvesting, or the elimination of a shrub layer by browsing) will promote persistence of Dennstaedtia.

Journal Article↗

PubMed2001

rbcL data reveal two monophyletic groups of filmy ferns (Filicopsida: Hymenophyllaceae).

The "filmy fern" family, Hymenophyllaceae, is traditionally partitioned into two principal genera, Trichomanes s.l. (sensu lato) and Hymenophyllum s.l., based upon sorus shape characters. This basic split in the family has been widely debated this past century and hence was evaluated here by using rbcL nucleotide sequence data in a phylogenetic study of 26 filmy ferns and nine outgroup taxa. Our results confirm the monophyly of the family and provide robust support for two monophyletic groups that correspond to the two classical genera. In addition, we show that some taxa of uncertain affinity, such as the monotypic genera Cardiomanes and Serpyllopsis, and at least one species of Microtrichomanes, are convincingly included within Hymenophyllum s.l. The tubular- or conical-based sorus that typifies Trichomanes s.l. and Cardiomanes, the most basal member of Hymenophyllum s.l., is a plesiomorphic character state for the family. Tubular-based sori occurring in other members of Hymenophyllum s.l. are most likely derived independently and more than one time. While rbcL data are able to provide a well-supported phylogenetic estimate within Trichomanes s.l., they are inadequate for resolving relationships within Hymenophyllum s.l., which will require data from additional sources. This disparity in resolution reflects differential rates of evolution for rbcL within Hymenophyllaceae.

Journal Article↗

PubMed2001

[Evaluation of saliva ferning test in diagnosis of Sjögren's syndrome].

OBJECTIVE: To evaluate saliva ferning test in (SFT) diagnosis of xerostomia in patients with Sjögren's syndrome (SS). METHODS: Dried samples of freshly produced saliva from 78 patients diagnosed as SS according to european community criteria and 80 healthy controls were examined by light microscopy. The crystallization was classified into 4 types according to the ferning phenomenon: uniformity, branching, spreading and integrity (type I normal and type II, III, IV abnormal). Then, the 78 patients underwent labial salivary gland biopsy. According to Tarpley's classification of labial gland biopsy, > or = 2+ was considered positive. RESULTS: (a) The sensitivity and specificity of SFT were 89.74% (70/78) and 83.75% (67/80) respectively. (b) Abnormal SFT was observed in 70/78 (89.74%) of SS and in 13/80 (16.25%) of normal controls. The differences of SFT in SS patients versus normal controls were significant (P < 0.01). (c) The sensitivity of SFT and labial gland biopsy had no significant differences (P > 0.05) as diagnostic tests in SS. CONCLUSIONS: SFT was valuable as a diagnostic test in patients suspective of SS.

Adolescent↗

PubMed1989

The fingerprint, a false-positive fern test.

Microscope slides were prepared to confirm the presence of ferning from a 32-week gestation with possible premature rupture of the membranes. Although no amniotic fluid was seen in the vagina, an atypical ferning pattern was produced and was again reproducible with fingerprints on the glass slide. Guidelines to recognize and avoid this source of error are outlined.

Adult↗

PubMed1986

The role of electrical phenomena in tip growth, with special reference to the developmental plasticity of filamentous fern gametophytes.

Cell expansion in many plant structures, including algal rhizoids, fungal hyphae, root hairs, and pollen tubes, is restricted to their apical tips. Endogenous electric fields are seen to accompany polarized growth in all tip-growing cells studied to date. The extensive studies on absorptive tip-growing structures have established that positive currents enter their elongating tips, with a portion of the entry current being carried by a localized calcium influx into the extreme tip. The resulting tip-to-base gradient in calcium concentration appears to be responsible for maintaining polarized growth in these systems, although it is uncertain whether this calcium effect is mediated via either electrophoretic or cytoskeletal mechanisms. In contrast, the few electrical measurements made on photosynthetic cells suggest that the orientation of their transcellular fields is transiently or permanently reversed relative to the fields in absorptive structures. In darkness, microelectrode measurements indicate that the apical tip of the fern filament is 5 mV electronegative relative to the base of the apical cell. This cellular dipole is perceived with the vibrating probe as a focused outward current that departs from the tip region and a more diffuse inward current that enters the lateral sides of the apical cell. The tip current is predominantly composed of protons, as can be identified with various cation-selective electrodes. This proton current is thought to help maintain localized wall expansion in the filament tip. Blue light mediates the major morphogenetic transition in fern gametophytes, i.e. the transition from the tip-growing filament to the planar prothallus. All the above electrical and ionic parameters change in the few minutes of irradiation before the filament tip starts lateral swelling. The plasma membrane at the extreme tip begins to hyperpolarize within 3 s, while the basal region shows a delayed, but greater response. The cellular dipole that had existed in darkness is thus abolished in 10 to 15 min after the start of irradiation. With the vibrating probe a more diffuse pattern of positive currents is observed to emerge from the tip as well as the subapical regions of the apical cell. Simultaneously, proton efflux increases in the subapical region; the resulting decrease in cell wall pH should help plasticize the lateral walls, which may, in turn, facilitate the process of lateral swelling over the next few hours.(ABSTRACT TRUNCATED AT 400 WORDS)

Electric Conductivity↗

PubMed1987

Induction of tumors in rats by bracken fern (Pteridium aquilinum) from Ouro Preto (Minas Gerais, Brazil).

1. The possible carcinogenicity of bracken fern (Pteridium aquilinum, common name: "Broto de Samambaia") which is used as food by the population of Ouro Preto (Minas Gerais, Brazil) and neighboring areas, was studied in rats. 2. Fifteen (6 female and 9 male) 45-day old Wistar rats were fed a diet containing dried bracken fern (5%, w/w) for up to 70 weeks. After death or sacrifice, the animals were carefully examined for tumors in the gastrointestinal tract, bladder, lungs, liver, and kidneys. 3. All experimental animals showed gastrointestinal tract tumors which were located mainly in the ileum. Most of the tumors were malignant lesions (adenocarcinomas and sarcomas), although benign adenomas were also present. One animal developed a lymphoma and none showed vesical tumors. 4. No tumors were detected in 11 control rats (5 female and 6 male). 5. These data clearly demonstrate that Pteridium aquilinum is carcinogenic for rats.

Animals↗

PubMedDate not supplied

[Effect of weightlessness on the water fern Azolla].

An exposure to 6-day weightlessness of the fern Azolla pinnata R. Br. symbiotically related to the nitrogen fixing alga Anabena azollae did not affect the main biological characteristics (growth, development and morphological structure) of both fern plants and algae. The exposure did not influence the growth rate or subsequent Azolla generations on the Earth.

Life Support Systems↗

PubMed1994

Concentration of ptaquiloside, a major carcinogen in bracken fern (Pteridium spp.), from eastern Australia and from a cultivated worldwide collection held in Sydney, Australia.

Two surveys of bracken fern for the concentration of the carcinogen ptaquiloside (PT) have been carried out, one of bracken fern from the eastern side of Australia and the other from a worldwide collection of bracken clones held in Sydney Australia. Bracken from eastern Australia contained concentrations of ptaquiloside ranging from 0 to 12,945 micrograms PT/g. From 91 samples 15% contained greater than 5,000 micrograms PT/g and 57% of samples contained more than 1,000 micrograms PT/g bracken on the dry weight basis. Ptaquiloside concentrations were highest in Pteridium revolutum and from P. esculentum from areas where bovine enzootic haematuria was known to occur. Bracken from the cultivated bracken clone collection from world-wide sources tended to have lower concentrations of ptaquiloside ranging from 0 to 9,776 micrograms PT/g. From 77 samples, 8% contained more than 5,000 micrograms PT/g and 35% contained more than 1,000 micrograms PT/g bracken. Samples from both the eastern Australia survey and the Australian representatives in the worldwide collection showed significantly higher concentrations of PT in the P. esculentum collected from the more southern states. In samples from the worldwide collection there were no statistical differences in the concentrations of PT in bracken between taxa.

Analysis of Variance↗

PubMed1976

Histogenesis of urinary bladder cancer induced in rats by bracken fern.

Histologic examination of the urinary bladders of albino rats fed bracken fern (Pteris aqulinum) showed epithelial hyperplasia in all test animals after 3 weeks of feeding and nuclear abnormalities at 4 to 6 weeks. Epithelial tumors were present in animals surviving more than 12 weeks, and invasion of subepithelial tissue occurred in animals sacrificed after this time. Carcinoma in situ, comparable to that in man, was not observed before invasive carcinoma, but was noted later in the surface epithelium adjacent to invasive carcinoma. Transitional cell carcinomas originated from hyperplastic epithelium, squamous cell carcinomas from metaplastic squamous epithelium, and papillary carcinomas from papillomas. Papillomas were preceded by epithelial hyperplasia. The results suggest that hyperplasia precedes bladder carcinoma in rats fed bracken fern.

Animals↗

PubMed2005

Drimanes and other terpenoids from the fern Thelypteris hispidula (Decne.) Reed.

The drimane-type sesquiterpenoids (-)-polygodial (1), (-)-isopolygodial (4), drimenin (5), and isodrimenin (6) were isolated from a pungent Argentine collection of the fern Thelypteris hispidula, along with other terpenoids. As the mentioned drimanes have been previously found in liverworts, the present results strongly support the theory that Pteridophytes and Bryophytes share the same line of evolution. Our present investigations indicate that two chemotypes of T. hispidula are widespread in the northwest of Argentina. Plants belonging to the pungent chemotype contain drimanes, while nonpungent plants lack drimanes.

Ferns↗

PubMed2004

Population genetic structure and phylogeographical pattern of a relict tree fern, Alsophila spinulosa (Cyatheaceae), inferred from cpDNA atpB- rbcL intergenic spacers.

Sequences of chloroplast DNA (cpDNA) atpB- rbcL intergenic spacers of individuals of a tree fern species, Alsophila spinulosa, collected from ten relict populations distributed in the Hainan and Guangdong provinces, and the Guangxi Zhuang region in southern China, were determined. Sequence length varied from 724 bp to 731 bp, showing length polymorphism, and base composition was with high A+T content between 63.17% and 63.95%. Sequences were neutral in terms of evolution (Tajima's criterion D=-1.01899, P>0.10 and Fu and Li's test D*=-1.39008, P>0.10; F*=-1.49775, P>0.10). A total of 19 haplotypes were identified based on nucleotide variation. High levels of haplotype diversity (h=0.744) and nucleotide diversity (Dij=0.01130) were detected in A. spinulosa, probably associated with its long evolutionary history, which has allowed the accumulation of genetic variation within lineages. Both the minimum spanning network and neighbor-joining trees generated for haplotypes demonstrated that current populations of A. spinulosa existing in Hainan, Guangdong, and Guangxi were subdivided into two geographical groups. An analysis of molecular variance indicated that most of the genetic variation (93.49%, P<0.001) was partitioned among regions. Wright's isolation by distance model was not supported across extant populations. Reduced gene flow by the Qiongzhou Strait and inbreeding may result in the geographical subdivision between the Hainan and Guangdong + Guangxi populations (FST=0.95, Nm=0.03). Within each region, the star-like pattern of phylogeography of haplotypes implied a population expansion process during evolutionary history. Gene genealogies together with coalescent theory provided significant information for uncovering phylogeography of A. spinulosa.

Biological Evolution↗

PubMed2005

Characterization and expression of a metallothionein gene in the aquatic fern Azolla filiculoides under heavy metal stress.

A cDNA encoding a type 2 metallothionein (MT) was isolated from Azolla filiculoides, termed AzMT2, accession no. AF482470. The AzMT2 transcript was expressed in sterile A. filiculoides that were free of the cyanobiont Anabaena azollae after erythromycin treatment, proving that AzMT2 is encoded by the fern genome. AzMT2 RNA expression was enhanced by the addition of Cd(+2), Cu(+2), Zn(+2) and Ni(+2) to the growth medium. The transcript level of AzMT2 correlated with the metal content in the plants. Temporal analysis of AzMT2 expression demonstrated that Cd(2+) and Ni(2+) induction of AzMT2 RNA expression occurred within 48 h. AzMT2-enhanced expression responded more intensely to the toxic Cd and Ni ions in A. filiculoides suggesting that AzMT2 may participate in detoxification mechanism. The more moderate response of AzMT2 to Zn and Cu ions, which are essential micronutrients, suggest a role for AzMT2 in metal homeostasis.

Amino Acid Sequence↗

PubMed2004

Novel mutant phenotypes of a dark-germinating mutant dkg1 in the fern Ceratopteris richardii.

The mutant dark-germinating 1 ( dkg1) of the fern Ceratopteris richardii was originally characterized by two phenotypes, germination in the dark and inhibition of germination by light. In this work, we examined whether other phenotypes are present in the gametophytic generation of the dkg1 mutant. Although dkg1 prothalli grown in darkness were elongated as in the case of the wild type, some developmental processes were found to proceed even in complete darkness: (1) the apical and subapical zones developed largely by forming a lateral meristem; (2) asymmetric cell division for rhizoid differentiation occurred in the subapical elongation zone; (3) an archegonium was formed in the proximity of the meristem; and (4) chloroplast relocation could occur without de novo protein synthesis. Furthermore, these processes were shown to be under the control of phytochrome in the wild-type gametophytes on the basis of red/far-red reversibility. These results indicate that the DKG1 gene is pleiotropic and is involved in several phytochrome-mediated responses in the gametophyte development of C. richardii.

Cell Division↗

PubMed2006

Independent origins of tetraploid cryptic species in the fern Ceratopteris thalictroides.

Ceratopteris thalictroides (L.) Brongn is a tetraploid fern species that contains at least three cryptic species, the south, the north and the third type. In this study we combined data from both chloroplast DNA (cpDNA) and nuclear DNA sequences of three diploid species and three cryptic species of C. thalictroides to unravel the origin of the cryptic species, particularly of the reticulate relationships among the diploid and tetraploid taxa in the genus Ceratopteris. Of the three diploid species examined, C. cornuta had cpDNA identical to that of the tetraploid third type plants, and this diploid species is a possible maternal ancestor of the tetraploid third type. Analysis of the homologue of the Arabidopsis thaliana LEAFY gene (CLFY1) identified ten alleles in the genus Ceratopteris, with six alleles found in C. thalictroides. The unrooted tree of the CLFY1 gene revealed four clusters. Each cryptic species showed fixed heterozygosity at the CLFY1 locus and had two alleles from different clusters of the CLFY1 tree. Consideration of the cpDNA sequences, CLFY1 genotypes of the cryptic species and CLFY1 gene tree in concert suggested that the cryptic species of C. thalictroides had originated through independent allopolyploidization events involving C. cornuta and two unknown hypothetical diploid species.

Base Sequence↗

PubMedDate not supplied

Lead accumulation in the aquatic fern Azolla filiculoides.

In this study, we characterized lead (Pb2+) accumulation and storage by the aquatic fern Azolla filiculoides. Lead precipitates were detected in the vacuoles of mesophyll cells of Azolla plants cultured for 6 d in rich growth medium containing 20 mg l(-1) Pb2+. Energy dispersive spectroscopy (EDS) analysis of the relative element content of leaves collected from these plants revealed a 100% increase in the levels of P, S, Na and Ca and a 40% decrease in Mg and Cl compared to the untreated plants. Both Azolla whole plants and isolated apoplasts were incubated for 6 d in 20 mg l(-1) Pb2+. Lead content in the whole plant composed 0.37%, 2.3% and 1.8% of the dry weight after 2, 4 and 6 d of growth, respectively, while the isolated Azolla apoplast contained 0.125%, 1.22% and 1.4% Pb2+, respectively. Lead content in Azolla whole plant increase by 200%, 100% and 22% after 2, 4 and 6 d of growth, respectively, when compared to Azolla apoplast. Dark, electron dense deposits of lead were observed in light and transmission electron microscope in leaf cells treated with lead. All the observed lead deposits were localized in vacuoles while larger lead deposits were found in mature leaves than in young leaves. No lead deposits were found in cells of the cyanobiont Anabaena when the plants were exposed to similar conditions. Activity and content of V-H+-ATPase were studied in Azolla plants grown in the presence of 20, 40 and 80 mg l(-1) of lead for a period of 4 d. Activity of V-H+-ATPase was increased by 190%, 210% and 220%, respectively, but the content of V-H+-ATPase was reduced by all lead concentrations.

Biological Transport↗

PubMed2006

Arsenic uptake by common marsh fern Thelypteris palustris and its potential for phytoremediation.

Hydroponic and soil cultivations of Thelypteris palustris, the common marsh fern, were used to investigate its potential for use in phytoremediation of arsenic (As) contaminated water or soil. ICP-MS analyses indicate that both roots and fronds accumulated arsenic in levels up to 100 times the concentration of treatment solutions of 250 microg/L and 500 mug/L arsenic, but values varied widely and there was no significant difference in concentrations in fronds between the control (no arsenic) and treatments. Plants exposed to 500 microg/L exhibited necrosis in their fronds, suggesting that Thelypteris palustris is not a good candidate for phyotoremediation of arsenic-contaminated sites.

Arsenic↗