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.

Structural positioning and orientational development in the vegetative organs of Poa pratensis with special reference to the rhizome axillary buds

1972 ◽  
Vol 50 (4) ◽  
pp. 743-750 ◽  
Author(s):  
John E. Fisher
Keyword(s):  
Apical Meristem ◽  
Poa Pratensis ◽  
Bilateral Symmetry ◽  
Main Stem ◽  
Axillary Bud ◽  
Initial Activity ◽  
Vegetative Organs ◽  
Initial Deviation ◽  
Lateral Bud ◽  
The Many

The apical meristem of P. pratensis is hemi-ellipsoidal, the plane of bilateral symmetry being readily recognizable. On each side of the apex a prominent pair of tiers of surface cells straddles the line of the plane of symmetry from the upper limit of the active promeristem and extends basipetally into the first and frequently second foliar primordia. Initiation of a new foliar primordium (phytomer) is centered in one or the other of the paired tiers. Occasionally, a single cell in a tier appears to undergo initial mitotic activity. The specific tier of initial activity determines the deviation from symmetry of the whole phytomer including that of the leaf at the top of the phytomer and of the lateral bud at its bottom. The subtending leaf does not determine the deviation from the plane of symmetry of the axillary bud. The first leaf of the axillary bud (not the prophyll) is positioned with its point of origin, hence its midrib, displaced away from the plane of symmetry of the main stem and with its larger semicircumference towards the main stem. Thus the deviation from bilateral symmetry of all the organs of the phytomer and the initial deviation from symmetry of the organs produced by the axillary bud are determined originally by the specific tier of cells in the promeristem of the main shoot that is stimulated into initial activity. This initial orientation of the axillary bud is the first of the many orientations that determines the pathway through the soil that the rhizome will ultimately follow.

Growth forms in the Alismatales. I. Alisma triviale and species of Sagittaria with upright vegetative axes

1979 ◽  
Vol 57 (21) ◽  
pp. 2325-2352 ◽  
Author(s):  
S. M. Lieu
Keyword(s):  
Seed Germination ◽  
Growth Form ◽  
Axillary Buds ◽  
Axillary Bud ◽  
Parent Plant ◽  
Growth Forms ◽  
Developmental Sequence ◽  
Sagittaria Latifolia ◽  
Different Populations ◽  
Vegetative Phases

Various aspects of the growth form of seven species of Alisma and Sagittaria were investigated. Of the four studied in detail, all have a short, upright stem which undergoes apical bifurcation to form the inflorescence and a continuation vegetative axis. Each season, three inflorescences are initiated in a distinct developmental sequence while phyllotaxy of the successive vegetative phases continues uninterrupted. The symmetry and development of both inflorescence and continuation growth are precise and similar in the species studied. There is greater variation in the pattern of development of axillary buds. This includes second-order axes attached directly to the parent plant (Alisma triviale), a new plant formed by each axillary stolon some distance away (Sagittaria latifolia and S. cuneata), or a whole sympodial system of stolon segments from each axillary bud as in Sagittaria subulata. Seed germination and seedling stages are very similar, and all show spiral phyllotaxy from the outset. The pattern of organization of each species remains relatively constant within and between different populations.

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.

Interaction of ecology, taxonomy and distribution in some Mesembryanthemaceae

Bothalia ◽  
1983 ◽  
Vol 14 (3/4) ◽  
pp. 653-659 ◽  
Author(s):  
H. E. K. Hartmann
Keyword(s):  
Plant Communities ◽  
Life Cycles ◽  
The Other ◽  
Distribution Data ◽  
Precipitation Data ◽  
Strong Correlations ◽  
Growth Forms ◽  
Structural Pattern ◽  
Arid Conditions ◽  
The Family

Many taxa of the family Mesembryanthemaceae show close correlations between distribution and environmental factors, e.g. occurrence on limestone or quartzite only, but few cases have been studied in detail. Recent investigations in anatomy, morphology, life cycles, physiology, and in energetic properties indicate that fundamentally different patterns are developed in adaptation to arid conditions, even in reaction to identical edaphic and climatic factors.On the other hand, little is known about the immediate influence of changes in the natural environment. Studies in populations of the subgenus Cephalophyllum of the genus  Cephalophyllum N.E. Br. show strong correlations between precipitation data and habit, which can superimpose genetic dispositions. In addition, growth forms are well adapted to certain types of plant communities, so that superficially, a diffuse structural pattern results.Long term studies, in the field and in the greenhouse, of growth forms in relation to time, to precipitation, and to associations, allow first suggestions for adaptive pathways in the evolution of the group, and the results form a basis for taxonomic decisions in this highly confused taxon. Finally, the example offers aspects for the better understanding of interaction between ecology and distribution data.

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.

Development of Paw Preference in Rats following Unilateral Cortical Ablations in Infancy

1975 ◽  
Vol 40 (1) ◽  
pp. 211-214 ◽  
Author(s):  
William G. Webster ◽  
Kristina Shoup
Keyword(s):  
Bilateral Symmetry ◽  
Cortical Lesions ◽  
Posterior Cortex ◽  
Paw Preference ◽  
Left And Right ◽  
Made In

Rats which received unilateral anterior cortical lesions in infancy manifested a preference for the paw contralateral to the intact hemisphere when tested at 5 wk. and at 10 wk. of age. That this effect was locus specific and was not due to a change in the over-all balance of activity between the hemispheres was indicated by the fact that similar lesions made in the posterior cortex did not influence which paw the animals subsequently preferred. The posterior lesions, however, may have lowered the frequency of ambidexterity, a finding interpreted in terms of theoretical arguments concerning bilateral symmetry and the discrimination and memory of left and right.

SIMULATION OF ENVIRONMENTALLY INDUCED GROWTH FORMS IN MARINE SESSILE ORGANISMS

Fractals ◽  
1993 ◽  
Vol 01 (03) ◽  
pp. 375-379 ◽  
Author(s):  
JAAP A. KAANDORP
Keyword(s):  
Light Intensity ◽  
Growth Process ◽  
Intensity Function ◽  
Growth Stages ◽  
Growth Forms ◽  
Filter Feeding ◽  
Stony Corals ◽  
New Material ◽  
Sessile Organisms ◽  
Made In

In marine sessile organisms (e.g. sponges and stony-corals), a distinction can be made in organisms that use filter-feeding, light or a combination of both, as a source of energy. In many of these organisms, growth takes place by the addition of layers of new material on top of the preceding growth stages that remain unchanged. The growth process of an organism that uses exclusively light and one that uses only filter-feeding for energy intake, are simulated using an iterative geometric construction in combination with, respectively, a light intensity function and a diffusion equation.

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.

scholarly journals Spontaneous Left Cardiac Isomerism in Chick Embryos: Case Report, Review of the Literature, and Possible Significance for the Understanding of Ventricular Non-Compaction Cardiomyopathy in the Setting of Human Heterotaxy Syndromes

2019 ◽  
Author(s):  
Jörg Männer
Keyword(s):  
Present Report ◽  
Bilateral Symmetry ◽  
Normal Function ◽  
Special Importance ◽  
Left Isomerism ◽  
Inner Organs ◽  
Cardiovascular Defects ◽  
Right Isomerism ◽  
Heterotaxy Syndromes ◽  
Made In

Except for a few species, the outer shape of vertebrates normally is characterized by bilateral symmetry. The inner organs, on the other hand, normally are arranged in bilaterally asymmetric patterns, which are of special importance for the normal function of the cardiovascular system of lung-breathing vertebrates. Deviations from the normal organ asymmetry can occur in the form of mirror imagery of the normal arrangement (situs inversus), or in the form of arrangements that have the tendency for development of bilateral symmetry, either in a pattern of bilateral left-sideness (left isomerism) or bilateral right-sidedness (right isomerism). The latter two forms of visceral situs anomalies are called &ldquo;heterotaxy syndromes&rdquo;. During the past 30 years, remarkable progress has been made in uncovering of the genetic etiology of heterotaxy syndromes. However, the pathogenetic mechanisms causing the spectrum of cardiovascular defects found in these syndromes remain poorly understood. In the present report, a spontaneous case of left cardiac isomerism found in a HH-stage 23 chick embryo is described. The observations made in this case suggest that hearts with left cardiac isomerism may have the tendency for development of a non-compaction cardiomyopathy caused by defective development of the proepicardium.

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