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  • Electronic Resource  (5)
  • 1990-1994  (2)
  • 1980-1984  (3)
  • 1
    Electronic Resource
    Electronic Resource
    Fructan contents and dry matter deposition in different tissues of the wheat grain during development (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 16 (1993), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The role of fructan metabolism in the assimilate relations of the grain of wheat (Triticum aestivum L.) was investigated by determination of the dry matter and fructan content of grain components at short intervals during grain filling. During the initial phase of rapid expansion, most of the assimilates entering the grain were partitioned to the outer pericarp. A large fraction of these assimilates were used for the synthesis of fructan. Dry matter deposition and fructan synthesis in the outer pericarp ceased at about 5d after anthesis. At the same time, the endosperm and the inner pericarp and testa started to accumulate dry matter at a fast rate. This was also associated with significant fructan synthesis in the latter tissues. The outer pericarp lost about 45% of its former maximum dry weight between 9 and 19 d after anthesis. This loss was due almost entirely to the near complete disappearance of water-soluble carbohydrates, most of which was fructan. The inner pericarp and testa accumulated dry matter until about mid-grain filling. The fructan contents of the inner pericarp and testa and the endosperm decreased slowly towards the end of grain filling. Most of the fructans in the inner pericarp and testa and the endosperm had a low molecular weight, whereas higher molecular weight fructans predominated in the outer pericarp. The embryo did not contain fructan. The presence of low molecular weight fructans in the endosperm cavity at mid-grain filling was confirmed. It is suggested that fructan synthesis is closely linked to growth-related water deposition in the different tissues of the wheat grain and serves to sequester the surplus of imported sucrose.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1993.tb00859.x
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  • 2
    Electronic Resource
    Electronic Resource
    The isthmus-tegmentum complex in the turtle and rat: a comparative analysis of its interconnections with the optic tectum (1984)
    Springer
    Experimental brain research 56 (1984), S. 509-522 
    Details
    ISSN: 1432-1106
    Keywords: Tectal connectivity ; Parabigeminal nucleus ; Isthmic nuclei ; Lateral tegmentum ; Comparative anatomy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Injections of horseradish peroxidase, wheat germ agglutinin and various amino acids into the optic tectum in both the turtle and rat, and into the nucleus isthmi magnocellularis (IsM) in the turtle were used to analyse the connections of the isthmustegmentum complex. The connectivities and the selective retrograde transport properties in certain tectal pathways were taken as a basis to define more accurately isthmus-tegmentum complex subdivisions. There were several main findings. In the turtle the projection from the tectum to the IsM originated in the stratum griseum periventriculare, whereas the projection from the IsM to the tectum terminated in the superficial tectal layers (both projections homolateral). The terminations of the pathway from IsM to tectum were not uniformly distributed throughout the tectal surface; rather, alternating zones of high and low termination density along the lateral dimension were observed. The turtle nucleus isthmi parvocellularis, receiving a few tectal fibers and afferents from the ipsilateral IsM, gave rise to a bilateral tectal projection. Evidence was obtained for a crossed collicular projection to the rat parabigeminal nucleus (Pbg) in addition to the established uncrossed one. GABA was retrogradely transported from the optic tectum to the Pbg in the rat, and to the dorsolateral mesencephalic tegmentum and the IsM in the turtle. After glycine injections into the optic tectum, the dorsomedial peri-parabigeminal tegmentum was retrogradely labeled in the rat, and the IsM in the turtle. An attempt was made to outline the parallelism between the organizations of the isthmustegmentum complexes in the turtle, pigeon and rat. It was concluded that some basic features in the inter-connectivity of the isthmus-tegmentum complex and other parts of the visual system have been preserved in evolution, despite the apparent loss of the isthmoretinal projection in mammals.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237992
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  • 3
    Electronic Resource
    Electronic Resource
    Is there a retinopetal system in the rat? (1984)
    Springer
    Experimental brain research 56 (1984), S. 502-508 
    Details
    ISSN: 1432-1106
    Keywords: Visual system ; Retinopetal cells ; Lateral mesencephalic tegmentum ; Retrograde tracing ; Rat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The centrifugal innervation of the retina was reinvestigated in albino and pigmented rats with intraocular injections of horseradish peroxidase (HRP), radioactive wheat germ agglutinin (WGA) and proline. No labeled cells were found in the brains injected with HRP and proline, except some eye muscle motoneurons in one case apparently involving orbital contamination from the injection. In the cases injected with WGA and having a survival time of at least two days cells were labeled in the lateral mesencephalic tegmentum, ventral to the parabigeminal nucleus and in the periaqueductal gray. Both these findings are most likely due to transneuronal anterograde-retrograde transport of the tracer through the superior colliculus. The results yielded no compelling evidence for the existence of a direct retinopetal pathway in the rat, which is in contrast to a recently claimed retinal projection originating from the pretectum. Special attention was paid to the labeling in the lateral mesencephalic tegmentum, an area giving rise to retinal projections in various submammalian species. This finding is discussed with regard to the possibility that also in the rat the lateral tegmentum exerts an early influence on visual input, but at the “higher” collicular level and not at the “original” retinal one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00237991
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  • 4
    Electronic Resource
    Electronic Resource
    Spatial distribution of growth rates and of epidermal cell lengths in the elongation zone during leaf development in Lolium perenne L. (1990)
    Springer
    Planta 181 (1990), S. 423-431 
    Details
    ISSN: 1432-2048
    Keywords: Cell (growth, division) ; Kinematics (leaf growth) ; Leaf elongation rate ; Lolium (leaf growth)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Relative elemental growth rates (REGR) and lengths of epidermal cells along the elongation zone of Lolium perenne L. leaves were determined at four developmental stages ranging from shortly after emergence of the leaf tip to shortly before cessation of leaf growth. Plants were grown at constant light and temperature. At all developmental stages the length of epidermal cells in the elongation zone of both the blade and sheath increased from 12 μm at the leaf base to about 550 μm at the distal end of the elongation zone, whereas the length of epidermal cells within the joint region only increased from 12 to 40 μm. Throughout the developmental stages elongation was confined to the basal 20 to 30 mm of the leaf with maximum REGR occurring near the center of the elongation zone. Leaf elongation rate (LER) and the spatial distributions of REGR and epidermal cell lengths were steady to a first approximation between emergence of the leaf tip and transition from blade to sheath growth. Elongation of epidermal cells in the sheath started immediately after the onset of elongation of the most proximal blade epidermal cells. During transition from blade to sheath growth the length of the blade and sheath portion of the elongation zone decreased and increased, respectively, with the total length of the elongation zone and the spatial distribution of REGR staying near constant, with exception of the joint region which elongated little during displacement through the elongation zone. Leaf elongation rate decreased rapidly during the phase when only the sheath was growing. This was associated with decreasing REGR and only a small decrease in the length of the elongation zone. Data on the spatial distributions of growth rates and of epidermal cell lengths during blade elongation were used to derive the temporal pattern of epidermal cell elongation. These data demonstrate that the elongation rate of an epidermal cell increased for days and that cessation of epidermal cell elongation was an abrupt event with cell elongation rate declining from maximum to zero within less than 10 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00195897
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  • 5
    Electronic Resource
    Electronic Resource
    The retinopetal system in the turtle Pseudemys scripta elegans (1983)
    Springer
    Cell & tissue research 234 (1983), S. 219-224 
    Details
    ISSN: 1432-0878
    Keywords: Visual system ; Retinopetal cells ; Retrograde tracing ; Turtle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Injections of 125I wheat-germ agglutinin or horseradish peroxidase into the eyes of turtles labeled retrogradely cells in a mesencephalic reticular area lying between the trochlear and the isthmic nuclei. Their number was small and they were found predominantly contralateral to the injected eye. These reticular neurons were not labeled following control injections into the orbital cavity and therefore are considered to project to the retina similar to correspondingly located neurons in some other vertebrates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00217415
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