scholarly journals Moss phyllid morphology varies systematically with substrate slope

2021 ◽  
Vol 154 (3) ◽  
pp. 419-431
Author(s):  
Caleb M. Turberville ◽  
Jesualdo A. Fuentes-González ◽  
Sydney Rogers ◽  
Jason Pienaar
Keyword(s):  
Surface Area ◽  
Growth Form ◽  
Light Exposure ◽  
Complex Model ◽  
Information Criteria ◽  
Length Variation ◽  
Growth Forms ◽  
Nutrient Quality ◽  
Moss Species ◽  
Prostrate Growth

Background and aims – Tracheophyte leaf morphology is well studied but it is unclear if the findings generalize to poikilohydric plants. We tested combinations of hypotheses to determine if microhabitat characteristics, including light exposure, moisture availability, and substrate slope, controlled for morphological differences between upright and prostrate growth forms, affect phyllid surface area and costa length of mosses.Material and methods – We quantified mean phyllid surface-area and costa lengths for four replicates of 38 moss species from Alabama. Phylogenetic comparative methods that model adaptation were used to evaluate the relative evidence for each hypothesis using information criteria. To further explore mechanistic explanations involving substrate slope, we tested whether mosses on vertical substrates differed from those on horizontal substrates in the average amount of water-retaining, nutrient-rich litter they accumulated.Key results – Substrate slope and growth form combined were the best predictors of phyllid surface area. Mosses growing on vertical substrates exhibited smaller phyllid surface area for both growth forms. Although growth form and phyllid length best explained costa length variation, a more complex model including substrate slope performed nearly as well. Within the prostrate growth forms, species growing on vertical substrates exhibit longer relative costa than those on horizontal substrates. We also estimated rapid rates of adaptation for both traits.Conclusion – The smaller phyllid surface area of both upright and prostrate growth forms is possibly an adaptive response to reduced habitat moisture-retention or nutrient quality that vertical substrates offer. The longer costa lengths of prostrate mosses growing on vertical surfaces relative to prostrate mosses on horizontal surfaces, possibly make up for the decreased ability of smaller phyllids to rapidly reabsorb water when it is available. Further work is required to determine if it is truly substrate slope itself that matters or other variables associated with the differences in slope, and to determine how general this phenomenon is.

RESPONSE OF DIFFERENT GROWTH FORMS OF POA ANNUA L. (ANNUAL BLUEGRASS) TO HERBICIDES APPLIED BEFORE OR AFTER EMERGENCE

1980 ◽  
Vol 60 (3) ◽  
pp. 947-952 ◽  
Author(s):  
S. I. WARWICK ◽  
A. S. HAMILL ◽  
P. B. MARRIAGE
Keyword(s):  
Biomass Production ◽  
Growth Form ◽  
Dry Weight ◽  
Poa Annua ◽  
Total Biomass ◽  
Growth Forms ◽  
Herbicide Treatments ◽  
Treatment Interaction ◽  
Prostrate Growth ◽  
Vegetative Component

The response of erect/annual and prostrate/perennial strains of Poa annua to herbicides was examined by treating soil with bensulide or chlorthal-dimethyl prior to emergence and by treating immature and mature plants with endothal or linuron. Chlorthal-dimethyl gave better control than bensulide as measured by a greater reduction in the number of seedlings surviving and dry weight of the survivors. Linuron was more effective than endothal in reducing biomass production of both immature and mature plants. Differential response of the erect and prostrate growth forms was not apparent for either bensulide or chlorthal-dimethyl, or for total biomass production of immature and mature plants in response to endothal or linuron. However, a significant growth form by treatment interaction was obtained for the vegetative component of mature plants, with the prostrate plants showing a greater weight reduction than erect individuals relative to the control. The weight of the reproductive component was equally reduced in both growth forms. Percent dry weight allocated to reproductive growth, which was 35 and 15% for the erect and prostrate growth form, respectively, remained relatively constant for both growth forms for all herbicide treatments.

An Experimental Analysis of Macrophyte Growth Forms as Fish Foraging Habitat

1991 ◽  
Vol 48 (1) ◽  
pp. 123-131 ◽  
Author(s):  
Michele Dionne ◽  
Carol L. Folt
Keyword(s):  
Plant Growth ◽  
Growth Form ◽  
Plant Density ◽  
Prey Capture ◽  
Capture Rate ◽  
Habitat Associations ◽  
Growth Forms ◽  
Plant Growth Form ◽  
Macrophyte Growth ◽  
Capture Rates

In this laboratory study we measured the independent effects of macrophyte growth form, plant density, and prey abundance on the foraging rate of the pumpkinseed sunfish (Lepomis gibbosus). We demonstrate that macrophyte growth forms are not all similar in their effects on fish foraging. Prey capture rates of pumpkinseeds foraging among Scirpus validus (cylindrical stems) were 53 and 365% times greater than for Potamogeton amplifolius (leafy stems) for cladoceran (Sida crystallina) and larval damselfly (Coenagrionidae) prey, respectively. Plant growth form influenced prey capture rates more than charges in natural plant density. Plant density effects ranged from none on damselfly capture rates to a 29% decline in cladoceran capture rate over a twofold increase in plant density. Our results indicate that in plant-structured habitats, variation in plant growth form can be an important determinant of fish foraging and habitat associations.

scholarly journals Competitive interactions between corals and turf algae depend on coral colony form

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1984 ◽  
Author(s):  
Thomas Swierts ◽  
Mark JA Vermeij
Keyword(s):  
Coral Reefs ◽  
Positive Relationship ◽  
Growth Form ◽  
Coral Species ◽  
Competitive Interactions ◽  
General Nature ◽  
Benthic Organisms ◽  
Growth Forms ◽  
Coral Colony ◽  
Turf Algae

Turf algae are becoming more abundant on coral reefs worldwide, but their effects on other benthic organisms remain poorly described. To describe the general characteristics of competitive interactions between corals and turf algae, we determined the occurrence and outcomes of coral–turf algal interactions among different coral growth forms (branching, upright, massive, encrusting, plating, and solitary) on a shallow reef in Vietnam. In total, the amount of turf algal interaction, i.e., the proportion of the coral boundary directly bordering turf algae, was quantified for 1,276 coral colonies belonging to 27 genera and the putative outcome of each interaction was noted. The amount of turf algal interaction and the outcome of these interactions differed predictably among the six growth forms. Encrusting corals interacted most often with turf algae, but also competed most successfully against turf algae. The opposite was observed for branching corals, which rarely interacted with turf algae and rarely won these competitive interactions. Including all other growth forms, a positive relationship was found between the amount of competitive interactions with neighboring turf algae and the percentage of such interaction won by the coral. This growth form dependent ability to outcompete turf algae was not only observed among coral species, but also among different growth forms in morphologically plastic coral genera (Acropora, Favia, Favites, Montastrea, Montipora, Porites) illustrating the general nature of this relationship.

Skeletal microstructure and mode of attachment in Palaeacis species (Anthozoa: Tabulata) from the Mississippian and Pennsylvanian of northeastern Oklahoma and northwestern Arkansas

1993 ◽  
Vol 67 (2) ◽  
pp. 167-178 ◽  
Author(s):  
Gregory E. Webb
Keyword(s):  
Growth Form ◽  
Growth Habit ◽  
Distal Portion ◽  
Free Living ◽  
Exterior Surface ◽  
Mode Of Attachment ◽  
Prostrate Growth ◽  
External Ornamentation

Three species of the Paleozoic coral Palaeacis are described from northeastern Oklahoma and northwestern Arkansas. Included are the Chesterian species P. carinata Girty and P. snideri n. nom., a replacement name for the junior homonym P. cuneata Snider, and the Desmoinesian? species P. erecta n. sp. Coralla of each species exhibit two types of microstructure that characterize two skeletal zones. The outer skeletal zone is composed of numerous parallel trabeculae, mostly between 0.2 and 0.3 mm in diameter, that lie perpendicular to, and have their accretionary surfaces on, the exterior surface of the corallum. Trabeculae are closely spaced laterally and are not organized into rows except uncommonly on the distal portion of some coralla. Where trabeculae coalesce into parallel rows, ornamentation on the corallum exterior consists of parallel ridges or rows of small nodes. Where trabeculae are irregularly arranged, external ornamentation consists of irregularly disposed nodes. The inner skeletal zone consists of radially fibrous stereoplasm arranged into discrete septal spines that coalesce into irregularly developed septal ridges in each calice. In P. erecta, septal spines merge into continuous layers of fibro-normal stereoplasm in some places. On the basis of microstructure, corallum morphology, and external ornamentation P. carinata and P. snideri can be allied with P. axinoides Smyth and P. robusta Webb. Palaeacis erecta falls within the same group on the basis of microstructure and ornament, but has a unique corallum morphology.Two distinct types of skeletal attachment occur in these Palaeacis species. Palaeacis carinata and P. snideri exhibit an encrusting attachment surface that results in a prostrate growth habit wherein smaller substrates were entirely engulfed, producing free-living coralla. Palaeacis erecta exhibits a small, circular attachment surface and an erect growth habit wherein most skeletal accretion occurs perpendicular to, and away from, the substrate. The substrate is not engulfed and the corallum remains attached and sessile throughout astogeny. Palaeacis erecta is, to date, the only Palaeacis species known to possess this erect, sessile growth form.

Growth forms in the Alismatales. II. Two rhizomatous species: Sagittaria lancifolia and Butomus umbellatus

1979 ◽  
Vol 57 (21) ◽  
pp. 2353-2373 ◽  
Author(s):  
S. M. Lieu
Keyword(s):  
Morphological Study ◽  
Growth Form ◽  
Bilateral Symmetry ◽  
Life Cycles ◽  
Axillary Bud ◽  
Growth Forms ◽  
Sagittaria Lancifolia ◽  
Adult Form ◽  
Lateral Bud ◽  
Made In

A comparative morphological study of Sagittaria lancifolia and Butomus umbellatus over their life cycles was undertaken. The two are very similar in adult form, characterized by apical bifurcation to form inflorescence and continuation growth as in other members of the Alismatidae.and also by rhizomatous growth with a subterminal apex. Embryo and seedling stages in S. lancifolia are comparable to other members of the Alismataceae previously studied. Rhizomatous form and bilateral symmetry are secondarily acquired during ontogeny. The inflorescence is leaf opposed and S. lancifolia is organizationally similar to other species of Alismataceae with upright vegetative axes. From this, a sympodial interpretation of the rhizome may be made. In contrast, the bilaterally symmetric growth form in Butomus is manifested from the start. The leaf-subtended inflorescence and other features of organization suggest that it cannot easily be compared with S. lancifolia or other members of Alismataceae. Here, a stronger case may be made for a monopodial construction. Axillary bud distributions support these conclusions. In addition, both species branch by a relatively precocious lateral bud associated topographically with the inflorescence.

The moss flora of the Auckland Islands, New Zealand, with a consideration of habitats, origins, and adaptations

1979 ◽  
Vol 57 (20) ◽  
pp. 2226-2263 ◽  
Author(s):  
Dale H. Vitt
Keyword(s):  
Species Richness ◽  
New Zealand ◽  
Polar Regions ◽  
Growth Forms ◽  
Common Pattern ◽  
Moss Species ◽  
Tussock Grassland ◽  
History Of

The moss flora of the Auckland Islands (50°40′ S latitude and 166°00′ E longitude) consists of 145 species and seven varieties in 75 genera. A detailed description of the habitat of each taxon is given. The vegetation, climate, and history of the islands, as they pertain to bryology, are reviewed. Four broad vegetational zones are recognized: forest, scrub, tussock grassland, and tundra as well as areas of herbfields and mires. Phytogeographically, the most common pattern of distribution is Australasian with 29% of the moss species found in both New Zealand and Australia. Other patterns are common as well. Discussion is orientated toward species richness variability in polar regions. The origins and adaptations of mosses in subantarctic landscapes are reviewed and correlations drawn between particular growth forms and individual moss floras and habitats.

scholarly journals Anpassung eines Fixed Regression Modells für die tägliche Zunahme von Fleckviehbullen mit Hilfe von Informationskriterien

2007 ◽  
Vol 50 (1) ◽  
pp. 47-58
Author(s):  
N. Mielenz ◽  
H. Krejčová ◽  
J. Přibyl ◽  
L. Schüler
Keyword(s):  
Fixed Effects ◽  
Covariance Structure ◽  
Information Criterion ◽  
Complex Model ◽  
Second Order ◽  
Information Criteria ◽  
Covariance Structures ◽  
Expected Gain ◽  
Bayesian Criteria ◽  
Daily Gain

Abstract. Title of the paper: Fitting a fixed regression model for daily gain of bulls using information criterion In this study the model choice is demonstrated exemplarily on data of 6405 Czech Simmental bulls using information criterion. Per bull up to 8 observations were available for the trait daily gain. Because the animals showed different age on control day, the expected gain curves were described in the population and within the herd*year*season-classes by second, third or fourth order Legendre polynomials of age. For optimization of the fixed effects and to choice the covariance structure of the repeated records the information criteria of Akaike (AIC), the Bayesian criteria (BIC) and the ICOMP-criteria, developed mainly from Bozdogan, were used. Within and over all covariance structures AIC selected generally the most complex model. On the other hand, BIC and ICOMP favoured a model with second order polynomials of age nested within the head*year*seasonclasses. All criterion selected models with nested second order polynomials within the herd*year*season-classes in comparison to models with non-nested polynomials of age.

scholarly journals Maximum Caliber can build and infer models of oscillation in a three-gene feedback network

2018 ◽  
Author(s):  
Taylor Firman ◽  
Anar Amgalan ◽  
Kingshuk Ghosh
Keyword(s):  
Gene Expression ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Theoretical Models ◽  
Complex Model ◽  
Information Criteria ◽  
Cell Protein ◽  
Protein Species ◽  
Feedback Network ◽  
Protein Number

AbstractSingle-cell protein expression time trajectories provide rich temporal data quantifying cellular variability and its role in dictating fitness. However, theoretical models to analyze and fully extract information from these measurements remain limited for three reasons: i) gene expression profiles are noisy, rendering models of averages inapplicable, ii) experiments typically measure only a few protein species while leaving other molecular actors – necessary to build traditional bottom-up models – unnoticed, and iii) measured data is in fluorescence, not particle number. We have recently addressed these challenges in an alternate top-down approach using the principle of Maximum Caliber (MaxCal) to model genetic switches with one and two protein species. In the present work we address scalability and broader applicability of MaxCal by extending to a three-gene (A, B, C) feedback network that exhibits oscillation, commonly known as the repressilator. We test MaxCal’s inferential power by using synthetic data of noisy protein number time traces – serving as a proxy for experimental data – generated from a known underlying model. We notice that the minimal MaxCal model – accounting for production, degradation, and only one type of symmetric coupling between all three species – reasonably infers several underlying features of the circuit such as the effective production rate, degradation rate, frequency of oscillation, and protein number distribution. Next, we build models of higher complexity including different levels of coupling between A, B, and C and rigorously assess their relative performance. While the minimal model (with four parameters) performs remarkably well, we note that the most complex model (with six parameters) allowing all possible forms of crosstalk between A, B, and C slightly improves prediction of rates, but avoids ad-hoc assumption of all the other models. It is also the model of choice based on Bayesian Information Criteria. We further analyzed time trajectories in arbitrary fluorescence (using synthetic trajectories) to mimic realistic data. We conclude that even with a three-protein system including both fluorescence noise and intrinsic gene expression fluctuations, MaxCal can faithfully infer underlying details of the network, opening up future directions to model other network motifs with many species.

scholarly journals Post-fire changes in plant growth form composition in Andean páramo grassland

2020 ◽  
Author(s):  
Maya A. Zomer ◽  
Paul M. Ramsay
Keyword(s):  
Plant Growth ◽  
Relative Abundance ◽  
Growth Form ◽  
Fire Suppression ◽  
Fire Regimes ◽  
Growth Forms ◽  
Vegetation Height ◽  
Plant Growth Form ◽  
Soil Temperatures ◽  
Three Phases

AbstractQuestionsFire suppression policies have been widely adopted in the páramo grasslands of the northern Andes to protect their biodiversity and ecosystem services. Páramos have been regularly burned for many years, and it is not clear how páramo vegetation will respond to significant changes in their fire regimes. This study investigates differences in plant growth form composition, light levels and soil temperatures in páramo plots representing a range of recovery times since the last fire.LocationReserva Ecológica El Ángel and La Bretaña Nature Reserve, Carchi, Northern Ecuador.MethodsWe assessed the frequency of ten páramo growth forms, vegetation height, soil temperature, and light intensity in fifteen fire sites with historical records of fire (<1 – 15 years since fire), and one recently unburned site (at least 40 years since fire). A chronosquence of sites was used to assess potential changes in plant community composition in post-fire succession of páramo.ResultsThe recovery of páramo vegetation after fire comprised three phases: initial recruitment with high growth form diversity, followed by reduced diversity, light and soil temperatures in dense tussock vegetation, and ultimately canopy height stratification with a return of diversity. All but one plant growth forms were represented in each of the three phases, and the changes reflected differences in relative abundance.ConclusionsPost-fire páramo succession is characterized by clear shifts in the relative abundance of plant growth forms, ending with (co-)dominance of upright shrubs. The long-term consequences of such shifts for biodiversity and ecosystem function, given the widespread adoption of fire suppression policies in the páramo need careful, evidence-based consideration.

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