Seed Morphology (seed + morphology)

Distribution by Scientific Domains

Selected Abstracts

Seed morphology of some species of Convolvulaceae from Egypt (Identification of species and systematic significance)

K. Abdel Khalik
Seed morphology of 31 taxa belong to six genera of Convolvulaceae from Egypt were examined by using light and scanning electron microscopy. Macro- and micromorphological characters, including seed shape, colour, size, surface, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and relief of outer cell walls, are presented. Three types of basic anticlinal cell wall boundaries and three types of relief outer cell walls are recognized and four different shapes of the outer periclinal cell wall are described. A key for the identification of the investigated taxa based on seed characters is provided. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Morphologie der Samen einiger Arten der Convolvulaceae aus Ägypten (Bestimmung von Arten und systematische Bedeutung) Unter Anwendung von Licht- und Elektronenmikroskopie wurde die Morphologie der Samen von 31 Arten aus sechs Gattungen der Convolvulaceae untersucht. Berücksichtigt wurden die makro- und mikromorphologischen Merkmale der Samen umfassend äußere Form, Farbe, Größe, Oberfläche, Form der Epidermiszellen, antiklinale und periklinale Zellwände und Relief der äußeren Zellwände. Drei Typen basaler antiklinaler Zellwände und drei Typen des Reliefs der äußeren Zellwände wurden nachgewiesen; ferner werden vier Formen der äußeren periklinalen Zellwände beschrieben. Ein Schlüssel zur Bestimmung der untersuchten Taxa auf der Basis der Merkmale der Samen wird vorgelegt. [source]

Seed morphology of Cuscuta L. (Convolvulaceae) in Egypt and its systematic significance

K. N. Abdel Khalik
The seed morphology of eight taxa of Cuscuta from Egypt has been studied using light and scanning electron microscopy, to determine the significance of seed coat features as taxonomic characters. Macro- and micromorphological characters, including seed shape, colour, size, epidermal cell shape, anticlinal boundaries, outer periclinal cell wall and relief of outer cell walls are presented. Three types of anticlinal cell wall boundaries are recognized and two different shapes of outer periclinal cell wall are described. The secondary sculpture of the cell wall varies from striate to micro-reticulate, and smooth to fine folds. A key for the identification of the investigated taxa based on seed characters is provided. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) Samenmorphologie von Cuscuta L. (Convolvulaceae) in Ägypten und ihre systematische Bedeutung Die Morphologie des Samens von acht ägyptischen Cuscuta -Taxa wurde mittels Licht- und Elektronenmikroskopie untersucht, um die Bedeutung der Merkmale der Samenschale für die Taxonomie zu ermitteln. Makro- und mikromorphologische Merkmale einschließlich Samengestalt, Farbe, Größe, Form der Epidermiszellen, antiklinale Zellwände, äußere Periklinal-Zellwände und Relief der äußeren Zellwände umfassend, wurden untersucht. Drei Typen antiklinaler Zellwand-Umrisse und zwei unterschiedliche Formen der äußeren Periklinal-Zellwände werden beschrieben. Die sekundäre Skulptur der Zellwände variiert von striat bis mikro-reticulat, und von glatt zu leicht gefaltet. Ein Bestimmungsschlüssel basierend auf den Samenmerkmalen der untersuchten Sippen wird vorgelegt. [source]

Seed morphology of Linaria species from eastern Spain: identification of species and taxonomic implications

Seed morphology of 15 taxa of Linaria from eastern Spain has been studied using stereoscopic and scanning electron microscopy. Four different morphological types are described according to features of the seed-coat surface. The type that includes winged seeded taxa is divided into three subtypes. Seed morphology of each type and subtype is described, compared, illustrated and discussed according to its taxonomic and biological implications. A key to identify the different species or groups of species is also supplied. 2001 The Linnean Society of London [source]

Differences in endozoochorous dispersal between aquatic plant species, with reference to plant population persistence in rivers

Summary 1. In river ecosystems, populations are continuously subjected to unidirectional downstream currents resulting in a downstream movement of populations. To ensure long-term population persistence in rivers, organisms must have a mechanism for upstream dispersal, which allows them to re-colonise upstream areas. 2. In this study we assessed differences in the potential for endozoochorous seed dispersal of Sparganium emersum and Sagittaria sagittifolia, two aquatic plant species with different seed morphologies, by mallard (Anas platyrhynchos) and teal (Anas crecca), two duck species with different body weights. 3. We found no significant differences in seed retrieval (the proportion of ingested seeds retrieved after gut passage) and seed retention time (time between seed ingestion and retrieval), between mallard and teal, despite the difference in body weights. We did find a significantly higher germination (%) over retention time of S. emersum seeds retrieved from teal compared with mallard, most likely related to a more efficient removal of the seed coat during passage through the gut of teal. 4. There were large differences between S. emersum versus S. sagittifolia in: (i) seed retrieval (22.65 ± 20.8% versus 1.60 ± 2.4%, respectively); (ii) seed retention time in duck gut, with a maximum of 60 h versus 12 h; (iii) the effect of gut passage on seed germination, with an increase of approximately 35% versus a decrease of 25%; and (iv) the effect of gut passage on seed germination rate, with an acceleration of 10 days versus a delay of 3 days on average. The results show that S. emersum has a higher potential for endozoochorous dispersal by ducks and postdispersal establishment than S. sagittifolia. 5. We propose that, in rivers, bird-mediated seed dispersal may promote re-colonisation of upstream areas, enabling long-term plant population persistence. [source]

Morphometric differentiation between populations of Papaver radicatum (Papaveraceae) in northern Scandinavia

The pattern of morphological variation was investigated in isolated northern Scandinavian populations of Papaucr radicatum, a perennial species with a disjunct distribution in the Scandinavian mountain range, Iceland and the Farces. Canonical variates analysis and Ward's clustering were applied to data sets from wild-collected seed and capsule material, and from cultivated leaf mated from seven populations of P. radicatum in northern Scandinavia, usually assigned to the sspp. subglobosum, hyperboreum and macrostigma. Automatized image acquisition and shape description techniques were used to describe variation in seed shape. The present study supports the multivariate analyses obtained with the southern Norwegian P. radicatum populations in that some of the assumed subspecies show inter-population variation and are not well delimited. In the analyses of capsule and seed morphology as well as leaf morphology, the populations of the sspp. hyperboreum and macrostigma are grouped together. Previous studies of chromosomal and morphological variation in southern Norwegian P. radicatum suggested that the degree of interracial differentiation was similar between all races regardless of their degree of geographic separation. The pattern of differentiation has been taken as a support of in Situ refugial survival during the Weichselian glaciation. As in similar multivariate analyses of southem Norwegian P. radicatum, the multivariate analyses of northern Scandinavian P. radicatum do not confirm such a scenario. The results rather point to the possibility that populations from the sspp. hyperboreum and macrostigna complex were separated during the post-glacial hypsithemal. The morphologically distinct ssp. subglobosum could have been isolated at an earlier stage. [source]

A Cladistic Analysis of the New World Species of Lotus L. (Fabaceae, Loteae)

CLADISTICS, Issue 3 2000
Ana M. Arambarri
The genus Lotus L. is a monophyletic group diagnosed by the possession of a standard claw with thickened infolded margin, stamens diadelphous, and the style hardened from the base. It comprises approximately 200 species distributed throughout the world. A cladistic analysis of the New World species was performed using 39 morphological and anatomical characters (29 from seed morphology and anatomy, 1 from plant habit, 1 from leaf morphology, 6 from flower morphology, and 2 from fruit morphology). Dorycnium, Edentolotus, Krokeria, and Pedrosia, of the Old World, and 28 species of the New World were considered terminal taxa. Tetragonolobus Scop. was chosen to root the cladograms and Dorycnium Mill. to reroot them. With Tetragonolobus the analysis yielded 15 equally parsimonious trees, each with a length of 74 steps, a consistency index of 0.62, and a retention index of 0.89. The 15 initial trees and the strict consensus tree defined 12 monophyletic groups. All terminal taxa form a monophyletic group diagnosed by the presence of a radicular lobe discernible to conspicuous (character 10); rim aril thick (character 13); stipules absent (character 31); and style simple and nondilated (character 36). The New World species form a monophyletic group on the basis of the seed relationship of length to width in hilar view 1.5:1 to 2:1 (character 5); micropyle linear-deltoid to bifurcate (character 19); and keel erostrate (character 33). Identical monophyletic groups were obtained when Dorycnium was used as root. These results are discussed in the context of data on cytology and morphology. [source]