Large Fronds Research Articles

Habitat traits and predation interact to drive abundance and body size patterns in associated fauna.

Habitat-forming organisms provide three-dimensional structure that supports abundant and diverse communities. Variation in the morphological traits of habitat formers will therefore likely influence how they facilitate associated communities, either via food and habitat provisioning, or by altering predator-prey interactions. These mechanisms, however, are typically studied in isolation, and thus, we know little of how they interact to affect associated communities. In response to this, we used naturally occurring morphological variability in the alga Sargassum vestitum to create habitat units of distinct morphotypes to test whether variation in the morphological traits (frond size and thallus size) of S. vestitum or the interaction between these traits affects their value as habitat for associated communities in the presence and absence of predation. We found morphological traits did not interact, instead having independent effects on epifauna that were negligible in the absence of predation. However, when predators were present, habitat units with large fronds were found to host significantly lower epifaunal abundances than other morphotypes, suggesting that large frond alga provided low-value refuge from predators. The presence of predators also influenced the size structure of epifaunal communities from habitat units of differing frond size, suggesting that the refuge value of S. vestitum was also related to epifauna body size. This suggests that habitat formers may chiefly structure associated communities by mediating size-selective predation, and not through habitat provisioning. Furthermore, these results also highlight that habitat traits cannot be considered in isolation, for their interaction with biotic processes can have significant implications for associated communities.

Resurrection of Tectaria cadieri from T. ingens (Tectariaceae) Based on Morphological and Molecular Data

Abstract— We demonstrate that Tectaria cadieri (Tectariaceae) is a distinct species in Vietnam after long being placed under the synonymy of T. ingens. Morphologically, T. cadieri is similar to T. ingens, T. setulosa, and T. trichotoma in their large fronds (up to 0.8‐2 m long), 3-pinnate laminae, fully free veins, and sori in two rows on ultimate segments. However, our observations show that T. cadieri differs from these species in the presence of linear, membranaceous stipe scales. Our analyses of five plastid regions (atpB, ndhF plus ndhF-trnN, rbcL, rps16-matK plus matK, and trnL-trnF) show that T. cadieri is not closely related to T. ingens, T. setulosa, nor T. trichotoma. Rather, T. cadieri is closely related to T. multicaudata, a morphologically distinct species with anastomosing veins. Along with a detailed description and illustrations for T. cadieri, we provide morphological comparisons and comments on the relationships between T. cadieri and morphologically similar species.

Eco-evolutionary contributions to community trait change in floating aquatic plants.

An entire community of organisms may become modified when its environment changes. These modifications can happen through physiological processes (plasticity), evolutionary processes (adaptation) or shifts in species composition (sorting). The outcome of these three sources of change constitutes the community's phenotypic response, but how they combine to drive community trait dynamics is not currently well understood. We have conducted a community selection experiment in which communities of short-lived floating aquatic plants were grown in a range of stressful conditions, and measured changes in their body size. Determinants of phenotypic change were assessed with a full community reciprocal transplant which led to estimates of the contributions of plasticity, adaptation, and sorting. Species were modified during the experiment by both plasticity and adaptation, but in either case the magnitude and direction of change differed among species. Sorting and adaptation were of equal magnitude but tended to act in opposite directions: in conditions where species with large fronds prevailed, each species evolved smaller fronds, and vice versa. We conclude that community trait dynamics cannot be understood simply by extrapolating the adaptive response of any single species to the whole community.

Light intensity drives different growth strategies in two duckweed species: Lemna minor L. and Spirodela polyrhiza (L.) Schleiden.

Duckweed species Lemna minor and Spirodela polyrhiza are clonal plants with vegetative organs reduced to a frond and a root in L. minor or a frond and several roots in S. polyrhiza. They reproduce vegetatively by relatively rapid multiplication of their fronds. The habit of S. polyrhiza (large fronds with up to 21 roots) makes it a strong competitor among representatives of the family Lemnaceae, probably due to different resource-use strategies compared to small duckweed. In our study, light was the resource that affected the plants before and during the laboratory experiment. We sampled the plants from natural habitats differing in light conditions (open and shady) and grew them for 16 days in a thermostatic growth room at 22 °C under a 16:8 photoperiod and three light intensities (125, 236, 459 µmol photons m–2 s–1) to investigate the trade-off between frond enlargement and multiplication. Both species from the open habitat had higher growth rates based on the frond numbers and on surface area of fronds compared to plants from the shady habitat. They adopted different species-specific strategies in response to the experimental light conditions. The species size affected the growth rates in L. minor and S. polyrhiza. Spirodela polyrhiza grew slower than L. minor, but both species grew fastest at medium light intensity (236 µmol m–2 s–1). Lemna minor maintained the growth rates at high light intensity, while S. polyrhiza slowed down. Spirodela polyrhiza responded to deteriorating light conditions by increasing its frond surface area, thus optimising light capture. Lemna minor from the shady habitat enhanced light harvest by increasing chlorophyll a concentration, but did not invest more in frond enlargement than L. minor from the open habitat. Under shady conditions, S. polyrhiza is likely to achieve an advantage over L. minor due to the larger frond size of the former. Our findings suggest the existence of a trade-off between size and number in duckweed.

The current rockweed, Ascophyllum nodosum, harvesting regime on the shores of Nova Scotia – a review

Ascophyllum nodosum is an ecologically and economically valuable species of brown seaweed found in Nova Scotia. The large fronds covered in airbladders create distinctive underwater canopy ecosystems in the intertidal zone. Ascophyllum is valuable as a soil supplement and fertilizer due to its biochemical composition. Commercial harvest of this wild resource began approximately sixty years ago and has been continuously exploited since. Careful management of Ascophyllum stocks is necessary to sustain the industry. In this literature review, the current harvesting regime of this seaweed in Nova Scotia is summarized and assessed in relation to harvesting regimes elsewhere and to the state of the intertidal marine ecosystem.Keywords: Ascophyllum nodosum, ecological impacts, intertidal ecology, resource management, rockweed harvesting, seaweed industry

Antrophyum nambanense, A New Vittarioid Fern (Pteridaceae; Polypodiales) From Vietnam

Abstract—A new species, Antrophyum nambanense, is described here based on the evidence from morphology and molecular phylogeny. Morphologically, short taeniform soral paraphyses and large fronds are the diagnostic characteristics of A. nambanense. Phylogenetically, it is most closely related to A. annamense, but can be readily distinguished from A. annamense by taeniform soral paraphyses (vs. filiform). We suggest A. nambanense is an allopolyploid of hybrid origin involving A. annamense and A. henryi, based on the evidence of morphology, phylogenetic position, chromosome number, and partially malformed spores. A description, photographs of key characters, distribution, conservation status, and ecology of the new species are presented. In addition, A. nambanense is also the first confirmed species with chlorophyllous spores in Antrophyum. Lastly, an updated key to all known Antrophyum species in Vietnam, including A. henryi as a new record for the country, is provided.

An emended and amplified description of Pecopteris apicalis Knight, a fern morphospecies of mid-Stephanian age from NW Spain

Extensive adpression material of the fern morphospecies Pectopteris apicalis Knight has been collected from overburden from opencast mining in the Paragido-Vallejo area oh the Barruelo Coalfield, close to the collection site of the holotype of the species. This has permitted a more detailed description of the key characteristics than was previously possible and an emended diagnosis. The large frond fragments demonstrate large pinnae of antepenultimate order, length in excess of 0.4 m, with apparent attachment to a very robust petiole in a tripinnate frond structure. Other diagnostic features of the species confirmed in this wide range of material cover the dimensions, acuminate shape, and terminal of last order pinnae, the range of dimensions and shape of pinnules and the characteristic consistently bifurcate venation. Fertile organs have been identified only on one specimen collected from another opencast working in the Barruelo Coalfield, at a lower level in the same stratigraphic unit. Although indistinct, the fertile organs comprise two rows of small circular sori on either side of the mid-vein, reminiscent of the genus Asterotheca, although the material does not permit reliable identification. Discussion of the possible systematic relationship of this species suggests the closet affiliation is with the cyatheoid group of pecopterid marattialean species. The Peragido-Vallejo material occurs within a low diversity flora which has undergone minimal transport from its site of growth, interpreted as in an interdistributary back-swamp area on a near-coastal alluvial plain

Contributions towards whole-plant reconstructions of Dicroidium plants (Umkomasiaceae) from the Permian of Jordan

Four Dicroidium species and associated fertile organs are here described from the late Permian Umm Irna Formation (Dead Sea Region, Jordan). Dicroidium irnense, D. jordanense and D. robustum, which were so far only known from the Wadi Himara locality, are now reported from several other sites, some yielding nearly complete fronds and excellently preserved cuticles; D. hughesii, a species so far only known from the Triassic, is here reported from the upper Permian. The largest species, D. robustum emend. nov., can be correlated with the pollen organ Pteruchus lepidus sp. nov. and the cupulate structure Umkomasia aequatorialis sp. nov. based on repeated co-occurrences and striking similarities in cuticular features. Dicroidium irnense is associated with Pteruchus frenguellii sp. nov. based on consistent co-occurrence. Dispersed Umkomasia seeds are common in all localities where Dicroidium occurs. The here described material comprises some of the most completely reconstructed species of Umkomasiaceae known to date. All Dicroidium plants are characterized by comparatively large fronds and both Pteruchus species have strongly elongate, strap-shaped microsporophylls, similar to Triassic Umkomasiaceae growing under comparable, seasonally dry conditions. Dicroidium first appeared during the late Permian in the paleotropical regions, survived the end-Permian biotic crisis, colonized large parts of Gondwana during the Triassic, and persisted in southern high-latitude refugia into the Jurassic. Umkomasiaceae thus show a remarkable resilience as the group survived two of the most severe mass extinctions in Earth history.

Textile substrate seeding of Saccharina latissima sporophytes using a binder: An effective method for the aquaculture of kelp

The macroalga Saccharina latissima holds promise as a widespread crop in northern Europe. Currently, seeded lines are cultured for 1–2 months within a hatchery until they become ≥1 mm sporophytes, which are then outplanted to a farm. Textiles are being developed as a cultivation substrate for macroalgae, however due to their large surface area, these need either direct in-situ seeding at the farm or a very short, high turnover hatchery period. Two materials, Kuralon twine and non-woven textile, were seeded using three S. latissima developmental stages: meiospore, gametophyte or juvenile sporophyte. The gametophyte and sporophyte stages were applied using a binder solution to adhere them to the materials. These were outplanted at a seaweed farm in the Sound of Kerrera, UK. After 5 weeks, fronds were significantly larger (45 ± 25 mm) and more abundant (20 ± 8·20 cm−1) when seeded with sporophytes over gametophytes or meiospores (8 ± 10 mm and 2 ± 2·20 cm−1). This reflects the growth advantage of outplanting juvenile sporophytes, since they are larger and more developed when outplanted. Higher fouling of filamentous algae was seen on the non-woven textile but this did not appear to affect growth. After four months, sporophyte seeded materials had the largest fronds and the greatest fresh mass of 2.1 ± 0.8 kg·20 cm−1, equivalent to simultaneously deployed hatchery reared twine (2.0 ± 0.1 kg·20 cm−1). Gametophyte seeding achieved 0.8 ± 0.6 kg·20 cm−1 while meiospore seeding achieved only 0.1 ± 0.1 kg·20 cm−1. No difference was found between growth on Kuralon twine or non-woven textile (p > 0.05), showing that both are suitable growth substrates. Seeding of juvenile sporophytes onto textile using the binder is demonstrated to be a successful method for the cultivation of S. latissima, and may require only 1% of the hatchery tankage, once optimised. It is expected that this method is transferable to the cultivation of other kelp species.

Morphological analysis of the Grand’Eury 1890 large frond fragment attributed to Odontopteris reichiana, from the Late Pennsylvanian (Stephanian) of the Gard coalfield (SE of Massif Central, France). Erection of Cyrillopteris gen. nov.

Morphological analysis of the Grand’Eury 1890 large frond fragment attributed to Odontopteris reichiana, from the Late Pennsylvanian (Stephanian) of the Gard coalfield (SE of Massif Central, France). Erection of Cyrillopteris gen. nov.

The calcareous brown alga Padina pavonica in southern Britain: population change and tenacity over 300years.

Understanding long-term persistence and variability in species populations can help to predict future survival, growth and distribution; however, sustained observations are exceedingly rare. We examine and interpret a remarkable record of the calcareous brown alga Padina pavonica (Phaeophyceae) at its northern limit on the south coast of England (50°N, 1–3°W) from 1680 to 2014, which is probably the longest compilation and review of any marine algal species. Over this period, which extends from the middle of the Little Ice Age to the present, there has been considerable variability in temperature and storminess. We identified a significant number of site extinctions in the second half of the nineteenth century, which coincided with cooler conditions and stormier weather. To interpret these changes, we measured recruitment, growth and production of tetraspores at sheltered and exposed sites in 2012–2014, years which had low and high spring temperatures. Potential spore production was greater at the sheltered site due to a longer growing period and survival of larger fronds. Delayed growth in the cooler spring resulted in smaller fronds and lower potential production of tetraspores by early summer. Yet in the warmer year, rapid initial growth caused higher sensitivity to damage and dislodgement by summer storms, which also limited potential spore production. Antagonistic responses to multiple stressors and disturbances make future predictions of survival and distribution difficult. Fronds of Padinapavonica are sensitive to both temperature and physical disturbances, yet vegetative perennation appears to have enabled population persistence and explained the longevity of remaining populations.Electronic supplementary materialThe online version of this article (doi:10.1007/s00227-015-2805-7) contains supplementary material, which is available to authorized users.

Ecology ofCodium fragileSubsp.FragilePopulations Within Salt Marsh Pannes in Southern Maine

Abstract The chloroplast haplotypes, ecology, growth, and reproduction of the introduced Japanese green alga Codium fragile were evaluated in four salt marsh pannes from Brave Boat Harbor, Kittery, Maine. All chloroplast haplotypes were identical and they matched the subsp. fragile delineated by Provan et al. Frond stature was seasonally variable and showed a pronounced increase in length from summer to early fall. Residual (i.e., overwintering) spring fronds were highly variable in stature compared to previous fall values, with some fronds only being ~ 0.5–1.0 cm. Frond stature and frequency patterns in the different pannes were related to their proximity to tidal channels, plus patterns of storm damage. Thus, one panne, which was closest to a tidal channel and had the lowest tidal level, exhibited the largest population frequency and smallest mean frond stature. The highest percent occurrence of gametangia occurred during late summer to early fall when the largest fronds were present. The reproductive p...

Cytotaxonomic Study of Hypodematium (Hypodematiaceae) from China

Chromosome numbers and reproductive biology of nine species of the fern genus Hypodematium (Hypodematiaceae) from China were investigated. The chromosome numbers of eight species are reported here for the first time: H. daochengensis n=41 (41 II); H. fordii n=40 (40 II), n=80 (40 II+40 I), 2n=120; H. glanduloso-pilosum n=41 (41 II), 2n=82, 2n=123; H. gracile n=41 (41 II); H. hirsutum n= 41 (41 II); H. microleptoides n=41 (41 II); H. sinense n= 40 (40 II) and H. squamuloso-pilosum n=41 (41 II). Two cytotypes, n=82 (41 II+41 I) and 2n=123 in H. crenatum, are reported for the first time. Our results showed that the species with these cytotypes are agamospermous triploids: H. crenatum n = 82 (41 II +41 I), H. glanduloso-pilosum n = 82 (41 II +41 I) and H. fordii n = 80 (40 II +40 I), based on the unequal size and presence of aborted spores in the sporangium, and the allotriploid hybrid chromosomes in the spore mother cell at the diakinesis stage of meiosis I. The remaining species are sexual diploids and tetraploids, based on the chromosome number n = 41 and n =82 at the diakinesis stage of meiosis I of spore mother cells. The relationships among habitat preferences, frond hairs and reproductive modes in Hypodematium are discussed and illustrated. It appears that plants with large fronds and sparse, thin hairs, living in humid and shady places undergo sexual reproduction, while small plants living in sunny and dry conditions with thick hairs undergo agamospermous reproduction. The distribution pattern and basic chromosome number all indicated the basic chromosome number x= 41 was plesiomorphic, whereas x=40 was apomorphic. Chromosome aneuploid changes occurred in this genus. The distribution of the sexual diploids and tetraploids and agamospermous triploids suggests that the genus might have originated in the Himalayas and dispersed from there to northeast Asia and Japan.

Population ecology of Palmaria palmata (Palmariales, Rhodophyta) from harvested and non-harvested shores on Digby Neck, Nova Scotia, Canada

Population ecology of Palmaria palmata is described from the intertidal zone of Digby Neck and adjacent islands of Nova Scotia. The primary objectives were: to evaluate the difference in habitat specialization and population structure of P. palmata between harvest and non-harvest shores, and to characterize differences in thallus structure and frond sizes between epilithic and epiphytic populations. Harvest shores were gently sloping boulder fields with boulders typically about 0.5-1.0 m with dense cover of P. palmata on many of the rocks. Non-harvest shores (with or without P. palmata) consisted of boulders that were smaller or larger than harvest shores, or bedrock; when P. palmata was present on nonharvest sites it was typically epiphytic on other algae (e.g., Fucus spp., Mastocarpus stellatus, Devaleraea ramentacea). Harvestable epiphytic populations occurred only in high current areas. While there was little difference in average cover of P. palmata harvest and non-harvest shores ( vs. , mean standard deviation [SD]), the cover of P. palmata on harvest shores was highly skewed such that individual boulders often had >90% cover while adjacent rocks had little. Frond length of large fronds was greater on harvested shores, and mean frond density () was three times higher than the mean density on the non-harvested shores. Frond lengths of entire epiphytic and epilithic frond complements of 119 thalli from harvest beaches showed no difference in mean size of the largest fronds, and no difference in frond number per holdfast when epiphytic and epilithic thalli were compared.

QUANTIFYING GROWTH AND CALCIUM CARBONATE DEPOSITION OF CALLIARTHRON CHEILOSPORIOIDES (CORALLINALES, RHODOPHYTA) IN THE FIELD USING A PERSISTENT VITAL STAIN1

Growth and calcium carbonate deposition rates of the coralline alga Calliarthron cheilosporioides Manza were quantified by monitoring fronds in the intertidal zone that had been chemically labeled with the nontoxic fluorescent brightener Calcofluor white. This vital stain effectively labeled apical meristems of coralline thalli in the field: fronds exposed for only 5 min had detectable chemical marks at least 1.5 years later. By distinguishing portions of thalli that developed before and after exposure, this methodology permitted accurate measurement of growth and calcium carbonate deposition at each meristem. In Calliarthron, meristematic activity declined with increasing frond size. However, because growing fronds dichotomize, the total number of meristems and the deposition rate of new calcified tissue both increased with frond size. Growth rates reported here suggest that large fronds may not be as old as previously estimated. The Calcofluor white method may improve demographic studies of corallines by resolving growth and age of fronds in the field and may facilitate studies of climate change on calcium carbonate deposition in these ecologically important, calcifying algae.

Respiratory Epithelial Adenomatoid Hamartoma in a Dog

A 6-month-old, intact, male Weimaraner dog presented to the veterinary teaching hospital for bilateral mucopurulent ocular and nasal discharge that began at approximately 10 weeks of age. A computed tomography scan showed an expansile soft-tissue mass involving both frontal sinuses, the ethmoid regions, and nasal cavities with lysis of the maxillary turbinates and hyperostosis of the walls of the frontal sinus. The dog was euthanized after complications during a trephination and biopsy procedure. At necropsy, a large, tan, papillary, gelatinous mass filled the entire nasal cavity and frontal sinus. The mass was composed of large fronds of loose fibrovascular stroma covered by a single layer of pseudostratified, columnar, ciliated epithelium and intermixed goblet cells. The cells occasionally formed glandular structures that were continuous with the surface epithelium. The mass was diagnosed as a respiratory epithelial adenomatoid hamartoma based on the morphologic appearance.

Retinal Vasculopathy in Fanconi Anemia

The authors present a case of Fanconi anemia with bilateral rapid onset retinal neovascularization and vitreous hemorrhage. The patient developed branch retinal vein occlusion in the left eye complicated by vitreous hemorrhage and was treated conservatively with intravitreal hyaluronidase injection. He declined vitrectomy and his visual acuity deteriorated to no perception of light. On follow-up, the right eye was noted to have clinical and angiographic evidence of sheathed vessels, an isolated large frond of neovascularization associated with areas of capillary nonperfusion. Panretinal photocoagulation and vitrectomy were performed with stabilization of vasculopathy and visual acuity. This case illustrates rapid onset peripheral occlusive vasculopathy with an atypical large isolated frond of neovascularization in a patient with Fanconi anemia resulting in blindness in one eye. Patients with Fanconi anemia would benefit from close and regular ophthalmological review.

RETINAL NEOVASCULARIZATION ASSOCIATED WITH A RETINAL ARTERIAL MACROANEURYSM

This case report describes an uncommon presence of a retinal arterial macroaneurysm complicated by retinal neovascularization. This is a case history of a 49-year-old woman presenting with preretinal, intraretinal, and subretinal hemorrhage with an adjacent retinal arterial macroaneurysm complicated by the development of retinal neovascularization. The neovascularization, intraretinal lipid, and retinal and preretinal hemorrhage resolved after laser photocoagulation, topical steroids, and nonsteroidal antiinflammatory agent treatment. The rapid development of a large frond of neovascularization is atypical for retinal arterial macular aneurysms and has not been previously reported.

Using Elevated Carbon Dioxide to Enhance Copper Accumulation in Pteridium Revolutum, a Copper-Tolerant Plant, Under Experimental Conditions

In our survey in the copper (Cu) mining area of China, a sun fern (Pteridium revolutum) was found to accumulate 30–567 mg Cu kg−1 DW (33 samples) in its fronds with a large frond biomass. Cu translocation factors in the plants varied from 0.09 to 3.88. In a greenhouse pot experiment, the effect of an elevated CO2 concentration (700 μL L−1) on Cu accumulation in plants was studied using three fern species (P. revolutum, Pteridium aquilinum, and Pteris vittata) grown in the Cu-contaminated soil. P. revolutum showed a higher Cu tolerance but its Cu translocation factor was lower than 1. At the elevated CO2 concentration, frond biomass of all species was significantly increased, as was the total Cu content in the fronds of P. revolutum and P. aquilinum. Our study suggests that P. revolutum could serve as a good candidate for phytoextraction of Cu-contaminated soils and that doubling the ambient CO2 concentration will facilitate its use in phytoextraction.

SELF-THINNING AND SIZE INEQUALITY DYNAMICS IN A CLONAL SEAWEED (SARGASSUM LAPAZEANUM, PHAEOPHYCEAE)(1).

Fronds of clonal seaweeds with extensive holdfasts relative to frond size are known not to self-thin during growth, even in crowded stands. We tested whether frond self-thinning would occur for such a seaweed since these traits are more similar to those of unitary seaweeds, which do self-thin in crowded conditions. We used Sargassum lapazeanum Setch. et N. L. Gardner (Fucales, Phaeophyceae) from the Pacific coast of Mexico, for which we first confirmed its clonal nature by performing a regeneration experiment in culture tanks. During the growth season (winter to late spring), S.lapazeanum stand biomass increased, while frond density and size inequality (Gini coefficient for frond biomass) decreased. These results indicate that self-thinning occurred at the frond level. We propose a conceptual model for frond dynamics for clonal seaweeds in general. In stands of clonal species with small fronds and relatively extensive holdfasts (particularly when holdfasts are perennial), frond dynamics would be determined mostly by intraclonal regulation, which seems to prevent excessive crowding from occurring. Such species display a positive biomass-density relationship during the growth season. On the contrary, in stands of clonal species with large fronds relative to holdfast size, frond dynamics would be determined mostly by interactions among genets. For such species, self-thinning may be detected at the frond level in crowded stands, resulting in a negative biomass-density relationship during growth.