Comparative wood anatomy of Atraphaxis taxa in Turkey

The wood anatomy of four Atraphaxis taxa that have natural distribution in Turkey—Atraphaxis billardieri Jaub. & Spach, Atraphaxis billardieri subsp. tournefortii (Jaup. & Spach) Lovelius, Atraphaxis spinosa L., and endemic Atraphaxis grandiflora (Willd.)—were compared in this study. The wood samples were sectioned according to standard techniques. Samples were macerated with Schultze’s method. Tangential and radial vessel diameters, intervessel pit diameters, vessel wall thickness, vessel elements length, dimensions of libriform fibres (lengths, widths, cell wall thickness and, lumen diameter), and uniseriate and biseriate ray heights were measured, and the number of vessels per mm2, number of rays per mm, and number of vessels per group were counted. The qualitative features such as growth rings, vessel grouping, presence of helical thickening and storied structure, vestured pits, type of perforation plate, and arrangement of axial parenchyma were determined. These four species of Atraphaxis shrubs differ in some wood characteristics such as growth rings, vessel grouping, vestured pits, height and density of rays, number of vessels per mm2, and the dimensions of the vessel.

On tylosis ultrastructure in Quercus cerris L.

A study of tylosis in European Turkey oak (Quercus cerris L.) shows correspondences in the formation of tyloses and of regular cell walls. The outer tylosis wall has a smooth, granular surface with simple perforations analogous to that of the primary wall of ordinary cells. The underlying wall stratum shows parallel oriented macro-fibrils, normally found in the secondary walls of regular cells. At the contact areas of tyloses, stabilizing seams can be observed. Various types of wall openings such as simple pits, blind pits and vestured pits were present. Also tylosis division was detected. The characteristics of parenchyma cell walls can be re-discovered in tyloses.

Detalles utraestructurales de la madera de algunas Boraginaceae de México

Vestured pits and different kinds of inclusions was searched for under the scanning microscope in five species of Cordia and one of Bourreria. Calcium oxalate crystals and tyloses were found in all five species of Cordia while in B. purpusii crystals were found but not tyloses . Vestured pits were found in C. alliodora , C. elaeagnoides and B. purpussi, starch was also found in the fibres and parenchyma of C. alliodora y C. dentata.

SYSTEMATIC WOOD ANATOMY OF HUBERIA, MICONIA AND TIBOUCHINA (MELASTOMATACEAE)

The wood anatomy of Huberia consimilis, Miconia amoena, M. mirabilis, M. rimalis and Tibouchina francavillana (Melastomataceae) is described and compared with other species from the same genera. All taxa share vestured pits, absent or inconspicuous growth rings, septate fibres, parenchyma-like tangential bands, and fibres shorter than 900 μm which is characteristic of the family Melastomataceae. Each species exhibited a set of wood anatomical characteristics that enabled its identification. Some traits were more relevant in distinguishing genera, such as composition of parenchyma-like tangential bands, vessel-ray pits, ray width, rays per millimetre and fibre length. Parenchyma-like tangential bands are described in great detail, and we propose a more specific nomenclature for their anatomical classification.

Characterisation of xylem conduits and their possible role in limiting the vase life of cut Acacia holosericea (Mimosaceae) foliage stems

Early desiccation limits the vase life of Acacia cut flowers and foliage and may be attributable to poor hydraulic conductivity (Kh) of the cut stems. Acacia holosericea A.Cunn. ex G.Don has been adopted as the test species to investigate the postharvest water relations of the genus Acacia. To understand potential constraints on Kh, xylem conduits in cut A. holosericea stems were anatomically characterised by light and scanning and transmission electron microscopy. Vessels with simple perforation plates and tracheids were the principal water conducting cells. Bordered vestured intervessel pits were present in xylem vessel elements. The majority of conduits (89%) were short at 1–5 cm long. Only 2% were 15–16 cm in length. Mean xylem conduit diameter was 77 ± 0.9 µm and the diameter profile showed a normal distribution, with 29% of diameters in the range of 70–80 µm. Simple perforation plates can offer relatively low resistance to water flow. On the other hand, bordered vestured pits and short xylem conduits can confer comparatively high resistance to water flow. Overall, the presence of bordered vestured pits, together with a high proportion of short xylem conduits and high stomatal densities (232 ± 2 mm–2) on unifacial phyllodes, could contribute to early dehydration of A. holosericea cut foliage stems standing in vase water. Further research will relate these anatomical features with changes in Kh and transpiration of cut foliage stems.