Morphology of vaucheria

Vaucheria is a genus of yellow-green algae, the taxonomy of which is based on the morphology of antheridia and oogonia. Distribution of Vaucheria in New Zealand is poorly understood. Only two studies have investigated phylogenetic relationships in the genus world-wide and these omitted some of the diversity found in New Zealand. We identified seven species of Vaucheria based on morphology of their reproductive structures. Two were described as new species (V. aestuarii and V. edaphica), two were reported for the first time from New Zealand (V. erythrospora and V. litorea), one has been reported previously (V. bursata), and the identification of the remaining two was inconclusive (Vaucheria cf. borealis and Vaucheria cf. conifera). The genetic variation and phylogenetic position of these species were studied using phylogenetic analyses of rbcL sequences. These showed the existence of morphologically indistinguishable cryptic species complexes in sect. Corniculatae. Our results were mostly consistent with the current morphology-based sectional classification of the genus.

ADVERTISEMENTS: In this article we will discuss about the vegetative and sexual methods of reproduction that occur in the life cycle of vaucheria . 1. Vegetative Reproduction in Vaucheria: The vegetative reproduction takes place by fragmentation. The thallus can break into small fragments due to mechanical injury or insect bites etc. A septum develops at the place of breaking to seal the injury. The broken fragment develops thick wall and later on develops into Vaucheria thallus. 2. Asexual Reproduction in Vaucheria: The asexual reproduction takes place by formation of zoospores, aplanospores and akinetes ADVERTISEMENTS: The entire protoplasm of the zoosporangium contracts to form oval zoospore. Opposite to each nucleus two flagella are produced making zoospore a multi-flagellate structure. A terminal aperture develops in zoosporangium by gelatinization of wall. The zoospore is liberated through aperture in morning hours (Fig. 2 C, D). Each zoospore is large yellow green, oval structure. It has a central vacuole which has cell sap and may be traversed by cytoplasmic strands. The protoplasm outer to vacuole has many nuclei towards the walls and chromatophores towards vacuoles. Two flagella arise opposite to each nucleus. This part of cytoplasm can be regarded equivalent to one zoospore. Fritsch (1948) regarded this kind of zoospore as compound zoospore or synzoospore as a number of biflagellate zoospores have failed to separate from one another. According to Greenwood, Mant...

The effects of habitat complexity have been considered important factors for the evolution of morphological complexity in organisms. We assessed the possible relationship between hydraulic niche conditions and the morphological complexity of algal filaments by sampling four species of macroalgae inhabiting different hydraulic niches in two freshwater streams. These algal species exhibit different fractal dimensions, which were measured by applying a grid method. The results showed that morphological differences are a function of hydraulic niche for stream macroalgae. Algae with complex shape ( Nitella wrightii and Batrachosperum puiggarianum) were established in slower flows, while algae with simpler filament shape ( Vaucheria sp. and Oedogonium sp.) were more likely to occur in faster water currents. The sites where the species occurred are a reflection of their ability to hold position, which is ultimately driven by their morphology. The influence of flow in stream habitats is an important factor for lotic macroalgae settlement and its effects can be related to evolutionary adjustment of body shape in these environments. We suggest that the morphological structure (here as fractal dimension) of freshwater macroalgae can be considered an adaptation to the costs and benefits exhibited by different hydraulic niches. • Adami, C., 2002. What is complexity? BioEssays 24: 1085–1094. • Allan, J. D. & M. M. Castillo, 2007. Stream Ecology: Structure and Function of Running Waters,...

Two species of the genus Vaucheria, V. lii Rieth and V. racemosa (Vaucher) DC., are reported from Connecticut and New England for the first time. Despite sampling over 150 freshwater habitats in Connecticut, each species has been located only at a single site. Culture conditions in the laboratory stimulated growth and, after extended periods of time, the production of gametangia allowing for the identification of each species. Despite its worldwide distribution, V. lii is shown to be a rarely collected species throughout its range. The Northeastern Naturalist is a peer-reviewed interdisciplinary scientific journal with a regional focus on northeastern North America, including eastern Canada. It features research articles on terrestrial, fresh-water, and marine organisms, and their environments. It focuses on field ecology, biology, behavior, biogeography, wildlife and fisheries management, taxonomy, evolution, anatomy, physiology, geology, and related fields. It is co-published with the Southeastern Naturalist (ISSN # 1528-7092). Both journals are identical in focus, format, quality, and features, thus providing an integrated publishing and research resource for eastern North America. The Eagle Hill Institute (formerly the Humboldt Institute) is located on the eastern Maine coast and is perhaps best known for the advanced and professional-level natural history science field seminars it has offered since 1987. The Institute actively promotes collaboration in education, rese...

Botany Studies Botany Studies – Botany is the study of plants and here you can get full educational definition and complete information related to botany. we provide full information about Plant Physiology, Plant Morphology, Plant Ecology, Plant Diversity, Plant Families, Photosynthesis And Botanical classification of plants vaucheria General structure of Vaucheria Vegetative structure:The thallus is filamentous. The filament is cylindrical, branched, tubular, erect coenocytic. The filament is attached to the substratum by hepteron. Hepteron is colourless branched rhizoid like structure. Filament increases in length by apical growth. Cross walls are absent. Cell structure: The cell wall is thin. It consists of inner layer of cellulose and an outer layer of pectic substances. The filaments are coenocytic. Septa is absent between the cells. Septum is present only at the base of reproductive structure. The cell has peripheral layer of cytoplasm. Cytoplasm surrounds a large central vacuole. Vacuole is filled with cell sap. Many small nuclei are embedded in the cytoplasm. Cytoplasm also contains small discoid chloroplast. Chloroplasts are small, oval, circular or elliptical. The pigments are chlorophyll a, chlorophyll e, beta-carotene and xanthophylls. Nanthophylls are dominant pigment. Its gives the thallus yellow-green colour. Pyrenoids are absent. The reserve food material is oil drops. General structure of Vaucheria Germination of spore, E- germination of sporangium Reprodu...

Authors • Abishek Muralidhar School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand • PAUL A. BROADY School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand • DUNCAN P. MACINTYRE School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand • MICHAEL D. WILCOX Auckland Museum, Auckland, New Zealand • ASHLEY GARRILL School of Biological Sciences, University of Canterbury, Private Bag 4800, Christchurch, New Zealand • PHIL M. NOVIS Allan Herbarium, Landcare Research, P.O. Box 69040, Lincoln 7640, New Zealand DOI: Keywords: Vaucheria, Xanthophyceae, rbcL, New Zealand, Canterbury Abstract Vaucheria is a genus of yellow-green algae, the taxonomy of which is based on the morphology of antheridia and oogonia. Distribution of Vaucheria in New Zealand is poorly understood. Only two studies have investigated phylogenetic relationships in the genus world-wide and these omitted some of the diversity found in New Zealand. We identified seven species of Vaucheria based on morphology of their reproductive structures. Two were described as new species ( V. aestuarii and V. edaphica), two were reported for the first time from New Zealand ( V. erythrospora and V. litorea), one has been reported previously ( V. bursata), and the identification of the remaining two was inconclusive ( Vaucheria cf. borealis and Vaucheria cf. conifera). The genetic variation and phyl...

ADVERTISEMENTS: Order: Siphonales Family: Vaucheriaceae Genus : Vaucheria Occurrence of Vaucheria : Vaucheria is represented by 54 species of which about 19 species are found in India. Vaucheria is found mostly in fresh water but about six species are marine and some are terrestrial found on moist soil. ADVERTISEMENTS: The terrestrial species like V. sessilis and V. terrestris form green mats on moist soil in shady places in green houses. V. amphibia is amphibous. V. jonesii was reported by Prescott (1938) in winter ice in U.S.A. The common Indian species of Vaucheria are V. amphibia, V. geminata, V. polysperma, V. sessilis and V. uncinata etc. Thallus : The thallus is made of long, cylindrical well branched filaments. The filament is aseptate, coenocytic structure. The thallus is attached to substratum by means of branched rhizoids or branched holdfast called the haptera. The thallus of V. mayyanadensis is differentiated in subterranean branched rhizoidal system and an erect aerial system. The filaments are rough, interwoven and appear as dark green felt like structure. Some species like V. debaryana show calcium carbonate incrustations. The branching may be lateral or dichotomous. The filaments are non-septate, the protoplasm with many nuclei is continuous along the entire length of thallus thus the coenocytic Vaucheria thallus makes siphonaceous structure (Fig. 1A, B). The septa formation occurs only during reproduction or in Gongrosira condition or for sealing of an in...