Browsing by Subject "morphology"

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    Morphological and genetic differentiation of Patella granularis (Gastropoda: Patellidae): recognition of two sibling species along the coast of southern Africa.
    (Wiley, 1998) Ridgway, T; Stewart, B; Branch, G; Hodgson, A
    Morphological and isozyme variations between 13 populations of the species hitherto named Patella granularis were investigated to see whether differences in shell structure between the west coast versus the south and east coasts of southern Africa are supported by other morphological features or by genetic differences. The shells showed a de®nite decrease in size from west to east, but this is correlated with productivity and is of no diagnostic use in distinguishing between populations. Discriminant functions analysis based on shell morphometrics failed to separate populations from the three coastal regions. Shells from the northern east coast do, however, have shell nodules with a dark pigmentation, distinctly separating them from those further south and west. No differences in radular or soft part morphology were detected between the populations, but the four northernmost populations on the east coast have a signi®cantly shorter Z looping of the gut than the other populations along the coast. Signi®cant microstructural differences in the sperm were also detected between these two groups of populations. Electrophoretic analysis of 16 enzyme loci failed to detect any signi®cant differences between the west and south coast populations, but revealed a genetic identity (Nei) of 0.528 as well as four diagnostic alleles between the four northernmost populations from the east coast compared with those to the south and west. The two genetically distinct forms occurred sympatrically at one of the study sites on the east coast (Coffee Bay). It was concluded the two groupings were suf®ciently different to warrant the recognition of a separate species, which is centred in KwaZulu-Natal on the east coast and extends south to Coffee Bay, from where it is replaced by P. granularis. There is, however, no evidence at all that the west coast populations are in any way separable from the remaining populations of P. granularis on the south coast.
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    Morphological characterisation of yeast colony growth on solid media using image processing
    (Springer, 1998) Dickason, G; Robinson, A; Sadr-kazemi, N; Harrison, S T L
    To rapidly determine the effect of environmental factors on yeast growth, a cell counting and colony sizing image analysis method was developed to characterise colony growth on solid media. A digitised microscopic image of the yeast was analysed using the Watershed algorithm for cell number determination and a morphological edge detection for colony size determination. The influence of temperature and physiological stress on yeast growth was then investigated over 12.5 h and data extracted by the image analysis method.
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    Morphology, evolution and taxonomy of Wachendorfia (Haemodoraceae)
    (1992) Helme, N E; Linder, H P
    Wachendorfia Burm. is a small genus endemic to the Cape Floral Region. Pour species are recognised in this study. Two species were originally described by Burman in 1757 and these were followed by numerous other descriptions of what is essentially one very variable species  (W. paniculaia Burm.). This variation is discussed and reasons are given as to why the recognition of formal infraspecific taxa is inappropriate. Formal taxonomic descriptions, distribution maps and a key to the species are provided. Rhizome morphology, leaf anatomy and pollen and seed coat structures were investigated and illustrations are provided. A cladogram was inferred and this is consistent with an ecological speciation model for the genus. The two species with the most restricted distribution (W. brachyandra W.F. Barker and W. pamfiora W.F. Barker) are considered to be the most recently evolved. Features of systematic and ecological interest (e.g. floral enantiomorphy) are discussed.
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    An overview of the biology of the desiccation-tolerant resurrection plant Myrothamnus flabellifolia.
    (Oxford University Press, 2007) Moore, John P; Lindsey, George G; Farrant, Jill M; Brandt, Wolf F
    Myrothamnus flabellifolia (Welw.) is a relatively large resurrection plant, a woody shrub between 0.5 m and 1.5 m tall (Sherwin et al., 1998) that grows on rock inselbergs (Porembski and Barthlott, 2000) throughout southern Africa (Weimarck, 1936; Van Wyk et al., 1997; Glen et al., 1999). The plant was first recorded in 1859 by Friedrich Welwitsch, who named the plant Myrothamnus (myron meaning aromatic and thamnos meaning bush) flabellifolia (meaning fan-like leaves) (Puff, 1978a; Glen et al., 1999), the leaves having a balsamic-like odour (Puff, 1978a; Glen et al., 1999). Weiss (1906) was the first to note the ‘miraculous manner’ with which the desiccated plant revived when supplied with water (Fig. 1A, B). Myrothamnus flabellifolia occupies an important position in traditional African folklore and medicine (Watt and Breyer-Brandwijk, 1962; Hutchings, 1996; Van Wyk et al., 1997). The Zulu name for the plant is ‘uvukwaba- file’ (wakes from the dead). The reviving ability is believed to be passed on to the ill person during treatment (Hutchings, 1996; Van Wyk et al., 1997). The plant is a geophyte possessing an extensive root system which extends into the crevices of the rocky slopes upon which it grows (Child, 1960; Glen et al., 1999). Myrothamnus flabellifolia can dehydrate its vegetative tissue, in particular its leaves, to an air-dry state. In this state, the leaves and stem segments curl and change colour from green to dullbrown (Farrant et al., 1999; Glen et al., 1999). When water is provided to the roots the plant re-hydrates its desiccated tissue and returns to its original colour and shape (Glen et al., 1999; Farrant et al., 2003). Since the last review on M. flabellifolia was written many years ago (Puff, 1978a) and since considerable work has been published in the last decade, this review focuses on recent advances in the understanding of the physiology, biochemistry and chemistry of M. flabellifolia.
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    Sex-related variation in morphology of helmeted guineafowl (Numida meleagris) from the Riemland of the northeastern Free State, South Africa
    (Bureau for Scientific Publications, 2005) Prinsloo, HC; Harley, V; Reilly, BK; Crowe, T
    In the hope of developing a relatively simple, nondestructive way of sexing adult helmeted guineafowl (Numida meleagris), sexual differences in body mass and in the size of head adornments of adult helmeted guineafowl sampled during the winter months in the Riemland district of the northeastern Free State, South Africa, were investigated. Males have statistically significantly larger values for all attributes than do females. However, no single attribute, nor a combination of them, can be used to sex guineafowl unambiguously.
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    The greater Omentum - its Morphology and function
    (1946) Wilkie_William
    The omentum has, from time to time, provoked sporadic reports on various aspects and, occasionally, a series of reports on one in particular. Hitherto no comprehensive account of the omentum and its function has been given. This thesis was undertaken with a view to correlating the available information and, in addition, performing further investigations along lines that were indicated. The Anatomy and Comparative Anatomy has received scant attention and the question of independent movement by the omentum has not yet been satisfactorily settled. These subjects have, therefore, been investigated and reported on at some length. In addition, some experiments of other observers have been repeated and a few original observations have been made and their significance discussea.
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    The void galaxy survey: photometry, structure and identity of void galaxies
    (2017) Beygu, B; Peletier, R F; Hulst, J M van der; Jarrett, T H; Kreckel, K; Weygaert, R van de; van Gorkom, J H; Aragon-Calvo, M A
    We analyse photometry from deep B-band images of 59 void galaxies in the Void Galaxy Survey (VGS), together with their near-infrared 3.6 μm and 4.5 μm Spitzer photometry. The VGS galaxies constitute a sample of void galaxies that were selected by a geometric-topological procedure from the Sloan Digital Sky Survey Data Release 7 data release, and which populate the deep interior of voids. Our void galaxies span a range of absolute B-magnitude from MB = -15.5 to -20, while at the 3.6 μm band their magnitudes range from M3.6 = -18 to -24. Their B-[3.6] colour and structural parameters indicate these are star-forming galaxies. A good reflection of the old stellar population, the near-infrared band photometry also provide a robust estimate of the stellar mass, which for the VGS galaxies we confirm to be smaller than 3 × 1010 M⊙. In terms of the structural parameters and morphology, our findings align with other studies in that our VGS galaxy sample consists mostly of small late-type galaxies. Most of them are similar to Sd-Sm galaxies, although a few are irregularly shaped galaxies. The sample even includes two early-type galaxies, one of which is an AGN. Their Sérsic indices are nearly all smaller than n = 2 in both bands and they also have small half-light radii. In all, we conclude that the principal impact of the void environment on the galaxies populating them mostly concerns their low stellar mass and small size.