A technique for examining the exterior of vessels by scanning electron microscopy is described. Features of vessels such as the union of vessel elements, the association of adjacent vessels, length of vessels, and deviations of vessels from their axial course can be studied.
The structure of the vessel-parenchyma pit membranes of Cucurbita maxima Duch. (Lauraceae) was studied with the scanning electron microscope. The main character of these membranes is the presence of numerous pectocellulosic and non-lignified excrescences, which are considered as part of the protective layer.
This study focuses on the interspecific variation in the distribution and structure of pits between vessels and imperforate tracheary elements. Specimens from the outer sapwood of eight species, in which vessel elements are frequently in contact with fibres and/or tracheids, were prepared using two different techniques and examined by field-emission scanning electron microscopy. In three species in which vessels are surrounded by vasicentric tracheids and/or fibres with distinctly bordered pits, pit pairs frequently occurred in walls between vessels and imperforate tracheary elements. In the five species in which vessels are in contact with fibres with indistinctly bordered pits, no or very few pit pairs were present, and blind pits were often found. Blind pits were exclusively present in vessel elements in some species, while they were restricted to imperforate tracheary elements in other species. The nature of vessel to imperforate tracheary element pitting appears to depend on tracheary element specialization.
The topochemistry of xylans was studied at the ultrastructural level in vessels of the wood of linden (Tilia plaryphyllos Scop.), by using an affinodetection method (xylan asegold labelling) and the cationic gold labelling for acidic charges.
The occurrence and morphology of natural tyloses and gums in the vessels of 50 Japanese hardwoods (15 ring-, 34 diffuseand 1 radial-porous woods) were investigated using SEM. Tyloses were present exclusively or predominantly in 23 species (12 ring-, 10 diffuse- and 1 radial-porous woods) and gums in 15 species (3 ring- and 12 diffuse-porous woods). In the pore zones of most of the ringporous woods both tyloses and gums first occurred in an earlier ring number from the bark than in the diffNse- and radial-porous woods. Tyloses and gums originated from both ray and axial parenchyma cells in most species which have pit pairs connecting these cells to the vessels. Except for four species, the maximum and minimum diameters of the inner pit aperture from vessels to parenchyma cells were greater than 5 and 2 µm, respectively, in those species with tyloses, whereas the diameters were less than these values in species having gums. The forms of tylosis blockings in heartwood vessels were closely related to parenchyma patterns.
Medieval treasuries often contained reliquaries made from objects with a different original function. When a chalice, ciborium or pyx was superseded by a larger and more precious vessel, it might be transformed into a reliquary. These objects were made of costly materials like silver gilt and
International Ports High Interest Vessels ( hiv s) may be those that cause suspicion due to their ports of origin. Port Security Units ( psu s) may attempt to deter and intervene into fishery and labeling crimes by paying additional attention to hiv s and Daily Vessel Reports ( dvr s) (Pramod, et
A reliable and simple microcasting method is applied to the study of the vascular structure in bamboo nodes; it provides new insights into their complexity, revealing the exact arrangement of branched vessels and clustered tracheary elements. Axial differentiation gradients in the metaxylem cell files, probable relics of the intercalary meristem, can also be found using this method. This anatomical finding can be linked to arecent hypothesis on the continuum in the tracheary element differentiation.