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At least 19 recordsLinked to original sources
PubMed2025

Harnessing fern stress adaptations: From evolution and ecophysiology to molecular biology.

Ferns are the second most diverse vascular plant lineage after angiosperms and have been a key ecological component of Earth's biodiversity for more than 380 million years. Importantly, ferns are sister to seed plants, providing a critical outgroup for understanding the evolution of seed plant features. Ferns are remarkably resilient to abiotic and biotic stresses due to a long evolutionary history with adaptations to diverse habitats, stresses, and herbivores. As a result, ferns produce a multitude of secondary metabolites with unique bioactivities; these chemicals are potentially linked to the adaptation of ferns to herbivory, various abiotic and biotic stresses, and changing environments. Assembled reference genomes and the identification of key metabolic compounds of multiple ferns have already made significant contributions to human health and well-being. Here, we review the recent scientific advances in fern research, including evolution, stress resistance, metabolites and medicinal utilization, and comparative multi-omics applications. We propose that integrated investigations involving ecological, physiological, and molecular techniques will facilitate the future research translation of fern resources in diverse areas including soil remediation, biopesticides, and medicine. Advances in our understanding of fern molecular biology will provide new insights into the evolution of land plants and promote the utilization of ferns for heightened environmental restoration, crop protection and human health.

Ferns↗
PubMed2026

Divergent trajectories of genome architecture and chromosome evolution in ferns and angiosperms.

Ferns and angiosperms represent the two largest vascular plant lineages but exhibit striking genomic and ecological contrasts. We investigated whether differences in genome size, chromosome architecture, GC content, and stomatal traits reveal divergent evolutionary trajectories between these lineages. We assembled the most comprehensive dataset to date, integrating genome size, chromosome number and size, GC content, and stomatal traits for over 1100 fern species and compared it with an extensive angiosperm dataset. Ferns exhibited markedly lower variability and c. 16-fold slower rates of chromosome size evolution than angiosperms. A persistent positive relationship between genome size and chromosome number in ferns suggests limited cytological post-polyploid diploidization. While ferns generally possess larger stomata, this difference disappears after accounting for genome size, indicating that nucleotypic constraints, rather than lineage-specific physiology, dictate stomatal dimensions. Both groups share a unimodal GC-genome size relationship peaking at c. 14 Gbp. Larger fern chromosomes imply lower genome-wide recombination rates, potentially limiting genetic reshuffling and adaptive potential. Our results highlight fundamentally divergent evolutionary trajectories, likely shaped by meiotic symmetry in ferns and meiotic asymmetry, possibly centromere drive, and post-polyploid diploidization in angiosperms, defining the functional and genomic landscapes of these lineages across deep evolutionary timescales.

Genome, Plant↗
PubMed1976

Identification of carcinogenic tannin isolated from Bracken fern (Pteridium aquilinum).

We attempted to isolate a carcinogenic substance from bracken fern (Pteridium aquilinum), a naturally occurring toxicant responsible for the production of chronic enzootic hematuria and urinary bladder cancer of cattle and carcinogenic for various target organs of several species. Hot methanol extracts of bracken fern were solubilized in water and extracted with chloroform followed by a mixture of n-butanol-butanone (1:1). That fraction was dried and triturated with ether-methanol (4:1), n-butanol, and finally absolute ethanol. The insoluble residue was dissolved in 10% aqueous methanol and passed through Dowex 1 OH-, Dowex 50 H+, or Dowex 1 OH- and then Dowex 50 H+ ion exchange resins. A condensed tannin, isolated from one ot the fractions, was identical to that isolated from bracken fern by the caffeine procedure used for the separation of tannins from other plant constituents. Three systems were used for bioassay; induction of bladder carcinoma by implantation of cholesterol pellets containing bracken fern fractions into the bladder lumens of mice; acute toxicity by ip injection of brachen fern fraction into mice; and growth inhibition of Escherichia coli. The following fractions induced significantly greater incidences of bladder carcinoma than did cholesterol pellets only: tannin, Dowex 50 H+, residue, n-butanol, and methanol. Tiliroside, a component of bracken fern fractions into the bladder lumens of mice; acute genic acid, and quercetin were not carcinogenic. Tannin was the most toxic (mean lethal dose: 0.16 mg/g) and carcinogenic. None of the carcinogenic fractions inhibited growth of E. coli.

Escherichia coli↗
PubMed1976

Naturally occurring and braken-fern-induced bovine urinary bladder tumors. Clinical and morphological characteristics.

Clinical and morphological characteristics of 139 naturally occurring and 20 braken-fern-induced urinary bladder tumors of cows were studied. Hematuria was prominent and occurred as early as 60 days after braken fern feeding began. Anemia and changes in leukocytes were late manifestations. Papillomas appeared as early as 1 year, whereas invasive carcinomas did not develop until 2.6 years after initiation of feeding. Twenty of 30 cows fed braken fern developed bladder tumors within 5.3 years. None of eight untreated control cows that lived 4 years or six that lived 10 years developed neoplasms. Naturally occurring and fern-induced bladder tumors were epithelial (35%) or mixed epithelial and stromal (55%). Papillomas occurred in 24% and carcinomas in 61% of naturally occurring cases, whereas there were papillomas (40%) and carcinomas (50%) in fern-fed cows. Naturally occurring tumors were metastatic to regional lymph nodes and lung. No metastases were detected in fern-fed cows.

Adenoma↗
PubMed1978

Screening aquatic ecosystems for mutagens with fern bioassays.

Recent researches on the royal fern, Osmunda regalis, have documented a high incidence of post-zygotic mutational damage in a population growing in a river heavily polluted with paper processing wastes, whereas genetic studies of nearby populations in nonpolluted environments failed to detect mutational damage. Intensive genetic and cytogenetic studies of mutation in O. regalis indicates that natural populations of homosporous ferns may be useful in situ bioassay systems for monitoring the presence of mutagens in aquatic ecosystems. Since these organisms are long-lived perennials with an ontogenetic system which stores mutational damage, they can be manipulated to give an integrated estimate of mutational damage for specified blocks of time (in units of years). Thus, the fern bioassay may be an inexpensive means of detecting both chronic low dose and episodic high dose inputs of mutagenic pollutants into aquatic ecosystems. The fern mutagen bioassay is based upon the detection of numerous categories of post-zygotic mutation load in natural fern populations. The frequency of sporophytic and embryonic lethals, leaf or root mutations, auxotrophic gametophytic mutations as well as numerous phenotypic alterations of gametophyte morphology can be routinely detected and quantified. In addition, various two-break chromosome aberrations (paracentric inversions, reciprocal translocations and ring chromosomes) can be readily screened for in the spore mother cells of many homosporous ferns.

Biological Assay↗
PubMed1978

Occupational allergic contact dermatitis due to leatherleaf fern Arachniodes adiantiformis (Forst) Tindale.

Leatherleaf fern has been imported from the United States, Honduras and Puerto Rico to the Federal Republic of Germany since 1966 and cultivated in Germany since 1970/71. It is slowly displacing the floral arrangements with asparagus used until now as filler and background material. This change is due primarily to its better keeping quality. Continuous contact with the leatherleaf fern induced an allergic contact dermatitis of the palms and fingers in a female florist. Patch tests with the leaf revealed the allergic origin of the dermatitis. Five fractions of a chromatographically separated extract of the fern were tested on sensitized guinea-pigs and on the patient. Only the first fraction gave a positive patch test response. By further separation colourless crystals of the contact allergen could be obtained. Elucidation of the structure is in progress. The sensitizer could only be detected during sporogenesis of the fern, that means when sporecapsules are present on the surface of the leaves.

Adult↗
PubMed2026

Co-option of stomata in the convergent evolution of fern nectaries.

Understanding the origin of new structures is a central goal of evolutionary biology. In many instances, novel phenotypes arise through heterotopy: the expression of a structure in a new location. Using bracken fern (Pteridium aquilinum) as a model, we combine genomics, transcriptomics and metabolomics to begin to explore the origin and developmental routes in the convergent evolution of ant-enticing nectaries. We observe that P. aquilinum does not exclusively express flowering plant 'nectary genes' during nectary development. Rather, this fern builds nectaries through co-option of stomata. Specifically, P. aquilinum heterotopically expresses canonical angiosperm stomatal regulatory genes, leading to stomatal development in novel positions along the petiole. These non-laminar stomata were co-opted for nectar secretion through the expression of putative sugar transport genes, forming secretory nectarostomata. This work provides two advances in our understanding of nectary evolution and the origin of complex structures. First, heterotopic expression of stomata, and later exaptation, represents one realized developmental mechanism for the evolution of nectar glands. Second, while there are many routes to nectary evolution, nectarostomata development is a repeatable path that has evolved in ferns and flowering plants, representing an impressive case of convergent evolution through the same developmental mechanism, despite over 400 million years of divergent history.

Plant Stomata↗
PubMed1978

Examination and evaluation of germination and protonemal development for Onoclea sensibilis fern spores treated with aflatoxin B1.

Experiments were designed to test the effects of aflatoxin B1 (AFB1) on germination and subsequent development of the gametophytes of the sensitive fern Onoclea sensibilis. AFB1 concentrations used were 0, 2.5, 5.0, 7.5, 10.0 and 12.5 muM. Preliminary studies indicated that, under all AFB1 concentrations tested, germination was maximum after 144 hrs. Additional studies revealed that during this time period protonemal growth was in the log phase. Percent germination was inhibited by increasing concentrations of AFB1; A 50% inhibition was noted at 12.5 muM. In addition, increasing concentrations of AFB1 caused a reduction in the total number of cells per protonema. Preliminary analysis indicated that this was caused by a reduction of the rate of cell production rather than total inhibition of cell division. A comparison of the dose-response curves for both of the above effects demonstrated that sensitivity to AFB1 starts at 2.5 muM. This may indicate that AFB1 is acting on a process common to both phenomena. The fern spore germination system could be a "simple" model system in which to study the site and mode of action of AFB1.

Aflatoxins↗
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↗
PubMed1977

Inhibition of carcinogenic effect of bracken fern (Pteridium aquilinum) by various chemicals.

The inhibitory effect of butylated hydroxyanosole (BHA), disulfiram, calcium chloride, and polyvinylpyrrolidone (PVP) on the intestinal and urothelial carcinogenicity of bracken fern (BF) was determined in albino rats. Of 10 groups of rats, one group received a normal diet, one received a BF-containing diet (one-third of diet by weight), four received a normal diet with one of the following supplements, and four received BF-containing diet with one of the following: BHA (5 mg/g diet); disulfiram (5 mg/g diet); PVP (50 mg/g diet); or calcium chloride (20 mg/g diet). At 12 months of the experiment, the following results were noted: in the BF-treated group, 30 rats (100%) exhibited intestinal tumors and 22 of 30 (73%) urinary bladder tumors. In the BF-BHA group, 15 of 20 rats (75%) showed intestinal tumors and 12 of 20 rats (60%) urinary bladder tumors. Of the 16 rats in the BF-disulfiram group, 12 (80%) had intestinal and 10 (62.5%) had urinary bladder tumors. In the BF-calcium chloride group, intestinal tumors arose in 16 of 23 rats (70%) and urinary bladder tumors in 4 of 23 rats (17%), while in the 28 BF-PVP rats, 26 (93%) exhibited tumors of the intestine and 5 (18%) tumors of the urinary bladder. Dietary BHA, disulfiram and calcium chloride decreased the incidence of intestinal tumors by about 25--30% (p less than 0.01). Similarly, PVP and calcium chloride inhibited BF-induced urinary bladder carcinogenesis by about 80% (p less than 0.001). No tumors were detected in groups receiving either normal diet or normal diet supplemented with BHA, disulfiram, calcium chloride or PVP.

Animals↗
PubMed1979

Demonstration of succinic dehydrogenase in mitochondria of fern egg cells at electron microscope level.

The use of ferricyanide in the presence of Cu++ to capture the ferrocyanide generated proved a reliable method for the location of succinic dehydrogenase in fern egg cells. The response of mitochondria-like nuclear evaginations was largely negative, but small patches of apparently authentic reaction product, absent in the controls, were occasionally encountered in their envelopes. From the point of view of deciding the nature of the nuclear evaginations the results were therefore equivocal.

Copper↗
PubMed1976

Thymidine phosphotransferase and nucleotide phosphohydrolase of the fern Asplenium nidus. General properties and inhibition by adenosine 3':5'-cyclic monophosphate.

1. Extracts of several plant species contained nucleoside-AMP phosphotransferase activity. The ratio of activity with thymidine to that with uridine as nucleoside substrate was essentially constant, both between species and throughout plant development. Evidence is presented that the total thymidine-AMP phosphotransferase activity of the leaves of Asplenium nidus (bird's-nest fern) and of Helianthus tuberosus (Jerusalem artichoke) increases during maturation. 2. Thymidine-AMP phosphotransferase was purified 22-fold from a very rich source of this activity, extracts of A. nidus. 3. A broad specificity towards both nucleoside and nucleoside 5'-monophosphate substrates is displayed by this preparation, and the evidence suggests that all could be due to a single enzyme. 4. Nucleosides that act as substrates will also inhibit phosphotransfer to other nucleosides, with Ki values close to the corresponding Km values found when utilized as substrates. 5. Ca2+-activated ATP phosphohydrolase was separated from the phosphotransferase by differential complexing to Blue Dextran in the presence of urea, whereas an AMP phosphohydrolase activity was closely associated with thymidine-AMP phosphotransferase through all separation techniques used. 6. Metal ions did not activate either of the latter two activities, and 1,10-phenanthroline was found to inhibit the phosphotransferase. 7. Km values for AMP for the respective activities were 0.11 mM (thymidine phosphotransferase) and 0.20 mM (AMP phosphohydrolase) and for thymidine (phosphotransferase only) 0.88 mM. 8. 3':5'-Cyclic AMP was found to inhibit both phosphotransferase and AMP phosphohydrolase activities, with Ki values of 0.056 mM and 0.15 mM respectively. It is suggested that this inhibitor would be of value in revealing the existence of thymidine kinase in plant extracts with high thymidine phosphotransferase activity.

Adenosine Monophosphate↗
PubMed1977

Ultrastructural and immunological demonstration of the nodulation of the European Alnus glutinosa (L.) Gaertn. host plant by the North-American Alnus crispa var. mollis Fern. root nodule endophyte.

The inoculation of the European Alnus glutinosa (L.) Gaertn. host plant by a crushed-nodule inoculum, prepared with the North-American Alnus crispa var. mollis Fern. root nodule, was successful. Fluorescein- and ferritin-labelled antibodies, specific against the A. crispa var. mollis root nodule endophyte (Lalonde et al. 1975), demonstrated the idenity of this endophyte in the resulting nodules. The nodulation process of this abnormal host-endophyte system was studied by light and electron microscopy. An excretion of host blebs containing electron-dense polysaccharide material, resulting in the formation of exo-encapsulation threads containing presumptive endophytic bacterial cells, was associated with deformed root hairs. Originating from an exoencapsulation thread, the endophyte penetrates the root hair cell and then migrates as a hypha toward the cortical cells of the root. Its migration in the cortical cells of the primary nodule results in the induction of a lateral root which develops as the true nodule. The ultrastructure of the A. crispa var. mollis endophyte developing in the primary and true nodule of the abnormal A. glutinosa host was similar to the one induced inside its normal A. crispa var. mollis host. The actinomycetal intruder was a branched and septate hypha able to produce septate vesicles. The endophyte was always encapsulated in an electron-dense polysaccharide material surrounded by a host plasma membrane envelope. However, in this abnormal host-endophyte system, the number of primary nodules formed per root system was drastically reduced, and their appearance was delayed by 1 to 2 weeks. The delayed nodules were effective in fixing nitrogen and able to support satisfactory plant growth in a nitrogen-free medium.

Antigens, Bacterial↗
PubMed1978

The fine structure of fertilization in the fern Marsilea vestita.

The ultrastructural details of fertilization in the fern Marsilea vestita, including gamete approach and fusion, the fate of the spermatozoid organelles and the development of a possible block to polyspermy are described. The spermatozoid approaches the egg through layers of mucilage that surround the megaspores. It moves down the neck of the archegonium into the cavity above the egg. In order to reach the egg, it must move through a small hole in the thick wall that lies across the top of the egg. The fusion of the plasma membranes of the gametes results in an outflow of egg cytoplasm into the clear space under the sperm plasma membrane, creating a fertilization cone. All the organelles of the fertilizing spermatozoid, including nucleus, mitochondrion, microtubule ribbon, multilayered structure, and flagellar band, with approximately 150 flagella, enter the egg cytoplasm. The nucleus enters as a condensed rod of chromatin with no nuclear envelope. The chromatin begins to disperse immediately and a new nuclear envelope is formed around the chromatin by egg endoplasmic reticulum. The mitochondrion and the microtubules of the ribbon and flagella are broken down, but the fates of the flagellar band and the multilayered structure have not been determined. After spermatozoid penetration, a new extracellular layer appears above the surface of the egg, beginning in the region of sperm penetration and spreading across the top of the egg. This layer may be important in preventing other spermatozoids from fusing with the egg.

Cell Fusion↗
PubMed1978

Oral treatment of human taeniasis by ethereal extract of male-fern (aspidium) preceded by the administration of hypertonic solution of magnesium sulphate.

29 Patients of ages varying from 12 to 60 years were treated orally with doses of 0.07 g/kg body weight of ethereal extract of male-fern, preceded by the administration of hypertonic solution of magnesium sulphate (15 g in 200 ml of water). All of them were previously treated with other anthelminthics without success. 25 of the patients obtained total cure. One woman expelled 14 scoleces of T. solium. The species determination for the 29 cases of Taeniasis revealed 3 cases of T. solium (10.3%) and 26 cases of T. saginata (89.7%).

Administration, Oral↗