The occurrence of Phlyctidium bumilleriae on two growth forms of Staurastrum pinque and other Staurastrum spp., in Lake Manitoba

1971 ◽  
Vol 49 (9) ◽  
pp. 1637-1641 ◽  
Author(s):  
Margaret J. Masters
Keyword(s):  
Growth Form ◽  
The Other ◽  
Growth Forms ◽  
Intermediate Growth ◽  
Intermediate Cells

Phlyctidium bumilleriae Couch was observed attacking Staurastrum pinque, S. chaetoceros, S. muticum, and S. cuspidatum var. divergens in Lake Manitoba during the summers of 1965–1968. S. pinque, the host present in the greatest numbers in the phytoplankton, occurred in a three-radiate, a four-radiate, and an intermediate growth form with three radii on one semicell and four on the other. Both in 1966 and 1967 the four-radiate form was more heavily attacked by Phlyctidium than the three-radiate form although the latter was present in greater numbers. In July 1968, it was the four-radiate form which was more numerous but still it was this form which Phlyctidium most heavily attacked. Intermediate cells succumbed to the fungus in proportions similar to the four-radiate form.

Growth and vegetative spread of Schizachyrium scoparium var. littoralis (Poaceae) in sand dune microhabitats along a successional gradient

1999 ◽  
Vol 77 (2) ◽  
pp. 219-229
Author(s):  
Teresa Valverde ◽  
Irene Pisanty
Keyword(s):  
Phenotypic Plasticity ◽  
Clonal Growth ◽  
Sand Dune ◽  
Growth Form ◽  
The Other ◽  
Schizachyrium Scoparium ◽  
Growth Forms ◽  
La Mancha ◽  
Reciprocal Transplants ◽  
Vegetative Spread

The architecture resulting from the iteration of modules during plant growth affects resource capture. Phalanx and guerrilla growth forms have been described as ends of a continuum regarding the spacing of modules in plants. In this study we investigated the growth form of the perennial, tussock-forming grass Schizachyrium scoparium Michx. var. littoralis (Nash) Hitchc. in three dune microhabitats at El Morro de la Mancha, southeastern Mexico: a mobile, a semi-mobile, and a stabilized site. We followed the growth of 15 genets at each site for two consecutive years and found that daughter-tussock formation was more frequent in the stabilized than in the semi-mobile or the mobile sites. Individual tussocks had a higher number of tillers in the mobile site than in the other two. Tiller production occurred within parental tussocks in the mobile site and in the form of daughter tussocks in the stabilized site. Reciprocal transplants suggested that phenotypic plasticity was responsible for the differences observed. Fertilization enhanced tiller production within parental tussocks but did not affect daughter tussock formation. Clearing experiments resulted in enhanced tiller production within tussocks. In these experiments, daughter-tussock production did not occur directionally towards nutrient-rich microsites. It appears that S. scoparium tillers are spaced at longer distances when resources are scarce and intraclonal competition is severe.Key words: clonal growth, growth form, nutrient availability, phalanx-guerrilla continuum.

Community structure of a rhodolith bed from cold-temperate waters (southern Australia)

2008 ◽  
Vol 56 (5) ◽  
pp. 437 ◽  
Author(s):  
A. S. Harvey ◽  
F. L. Bird
Keyword(s):  
Community Structure ◽  
Red Algae ◽  
Growth Form ◽  
The Other ◽  
Growth Forms ◽  
Free Living ◽  
Coralline Red Algae ◽  
Reliable Identification

Rhodolith beds are aggregations of free-living non-geniculate coralline red algae (Corallinales, Rhodophyta), with a high biodiversity of associated organisms. This is the first detailed study of a rhodolith-bed community from the cold-temperate waters of southern Australia. This bed, located at 1–4-m depth in Western Port, Victoria, is composed of four rhodolith-forming species (Hydrolithon rupestre (Foslie) Penrose, Lithothamnion superpositum Foslie, Mesophyllum engelhartii (Foslie) Adey and Neogoniolithon brassica-florida (Harvey) Setchell & Mason). M. engelhartii has a foliose growth form and the other three species have fruticose growth forms. Detailed descriptions are provided for all species, allowing reliable identification. Comparisons with other rhodolith beds and reported rhodolith-forming species, both in Australia and worldwide, are also provided. The invertebrate cryptofaunal community was quantified for two rhodolith-forming species. The density of cryptofauna inhabiting foliose and fruticose rhodolith growth forms did not differ significantly and neither did abundance of individual phyla. Mean density of fauna was 0.4 invertebrates cm–3, the majority of which were polychaete worms. Comparisons of fauna associated with other rhodolith beds are also provided. A study of the vitality of the rhodolith bed showed dead rhodoliths are more abundant than live rhodoliths. Possible reasons for reduced bed vitality are explored.

Comparative leaf development of aerial and aquatic growth forms of Myriophyllum aquaticum

Botany ◽  
2013 ◽  
Vol 91 (7) ◽  
pp. 421-430 ◽  
Author(s):  
M.D. Shafiullah ◽  
Christian R. Lacroix
Keyword(s):  
Apical Meristem ◽  
Epidermal Cells ◽  
The Other ◽  
Developmental Study ◽  
Growth Forms ◽  
Myriophyllum Aquaticum ◽  
Stages Of Development ◽  
Qualitative And Quantitative ◽  
Early Stages ◽  
Other Hand

Myriophyllum aquaticum (Vell.) Verdc. produces two morphologically different forms of leaves based on whether they are aerial or aquatic. The objective of this study was to determine whether there are any similarities or differences between these two growth forms during their early stages of development. A comparative developmental study of aerial and aquatic growth forms of M. aquaticum was conducted from a qualitative and quantitative perspective using a scanning electron microscope. The pattern of leaf and lobe initiation such as their origin and shape were similar in both growth forms until the fourth plastochron (stage P4). Differences between the two growth forms became evident from stage P5 onward, where a larger shoot apical meristem (SAM), elongated epidermal cells, shorter and slightly more numerous lobes, as well as the presence of appendage-like structures characterized aquatic growth forms. On the other hand, aerial growth forms had smaller SAM, bulb-like epidermal cells, and longer and slightly less numerous leaf lobes. Significant differences between growth forms were noted for parameters such as volume of SAM, length of terminal, first, and middle lobes, as well as the length from first to last lobes. The volume of the SAM of aquatic shoot tips was always greater than aerial forms. On the other hand, lobes of aerial forms were always longer than the aquatic counterpart during early stages of development. This study on the development of M. aquaticum shows that the aerial and aquatic growth forms diverge from their early stages of development.

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.

Photographic Records of Living Oscular Tubes of Leucosolenia Variabilis II. Spicule Growth, form and Displacement

1964 ◽  
Vol 44 (2) ◽  
pp. 311-331 ◽  
Author(s):  
W. Clifford Jones
Keyword(s):  
Growth Form ◽  
The Other ◽  
Significant Movement ◽  
Photographic Records

When the oscular tube grows the spicules tend to separate from one another, but the separation is not uniform; local displacements of spicules occur with respect to other spicules in the vicinity. The same is found when the tube elongates while constricting, or changes shape in other ways. The spicule displacements reveal that the mesogloeal matrix is plastic. The spicules are probably anchored to the surface epithelia, the system of anchorage varying with time and from one spicule to another.Small growing spicules may rotate through considerable angles and move relative to the fully grown spicules in their vicinity. The relative movements are most frequently towards the osculum. They are attributed to displacements of either the mesogloeal matrix or the internal epithelium, each relative to the other. They are not likely to be caused by the concerted amoeboid activity of the founder calcoblasts.The monaxons tend to maintain their positions and orientations relative to the tri- and quadri-radiate spicules, apart from small localized displacements. Thus no significant movement of the pinacoderm relative to the rest of the wall could be deduced.Fragments of broken spicules likewise tend to retain their relative positions and orientations in the spicule arrangement, though some moved or rotated by quite considerable amounts.Spicules occasionally disappeared from the wall of some tubes. Monaxons were shed relatively easily, probably as a result of the spicule crowding associated with contraction of the tube. Some tri- and quadri-radiates were also shed through the pinacoderm. In some tubes spicule protrusion occurred at the oscular edge.

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.

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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