Browse results

You are looking at 1 - 10 of 3,501 items for :

  • Upcoming Publications x
  • Just Published x
  • Search level: Chapters/Articles x
Clear All

Abstract

The anatomical structure of the bamboo stem is characterized by vascular bundles comprising the xylem, phloem, and sclerenchyma fibrous sheaths as well as parenchymatous ground tissue in which the vascular bundles are embedded. The composition of the stem is the main factor influencing the anatomical characteristics of circular bamboo, which shows considerable variation in the radial direction. However, most species of Chimonobambusa have square stems. Here, we tested the hypothesis that circumferential variation exists in the cross-sectional anatomy of this species. We analysed fibre morphology and the cross-sectional structural characteristics of vascular bundles of Chimonobambusa quadrangularis (Fenzi) Makino and their associated circumferential and radial variation in cross-sections. Microscopic observations were conducted to identify, measure, and compare fibre morphology and the structural characteristics of vascular bundles, including both circumferential and radial anatomical variation. Vascular bundles occurred as undifferentiated, semi-differentiated, and open types in the radial direction with no changes in the circumferential direction. The average length, width, and ratio of fibre length to width were 1463.6 μm, 12.3 μm and 119.3 in the corner region, and 1452.7 μm, 12.8 μm, and 111.3 in the side region, and there were significant circumferential and radial differences in length, width, and the ratio of fibre length to width (p<0.001). The circumferential variation in density of vascular bundles, the ratio of fibre length to width, radial to tangential diameter ratio of vascular bundles, and the proportion of sclerenchyma were greater in the corner regions than the side regions. The variation in fibre width and the proportion of parenchyma were greater in the corner regions than in the side regions. The density of vascular bundles and proportions of sclerenchyma were greater in the outer stem compared to the inner stem, whereas the length, width, and ratio of fibre length to width were greatest in the centre compared to the inner and outer zones. Circumferential variation of the density of vascular bundles, fibre length and fibre width occurred in the central and outer stem zones. These findings confirm that there are significant anatomical variations in both the circumferential and radial directions and provide a scientific basis for the rational use of Chimonobambusa quadrangularis.

In: IAWA Journal
Authors: Le T. Ho and Frank M. Thomas

Abstract

Wood density constitutes an integrative trait of water relations and growth. We compared the recently developed blue intensity (BI) method, which has only rarely been applied to tropical conifers, for determining wood density with anatomical analyses in studying the three rarely investigated palaeotropical pine species Pinus kesiya, P. dalatensis and P. krempfii, which co-occur in South-Central Vietnam, but differ in their distribution areas. For species comparisons, we also calculated the hydraulic conductivity of the xylem with the Hagen-Poiseuille equation and the water potential causing 50% loss of hydraulic conductivity (Ψ50) based on the anatomical analyses. We hypothesized (i) that the BI values are correlated with the cell wall fractions, the calculated hydraulic conductivity and the Ψ50 values; and (ii) that the wider occurrence of P. kesiya, which also can grow at drier sites, is reflected by higher wood density, lower hydraulic conductivity, lower (more negative) Ψ50 values and a smaller variation in the wood anatomical features across the years compared to the other two species. In agreement to our hypotheses, the results of the BI and the anatomical method were closely correlated, especially for sapwood, and P. kesiya exhibited features that are related to the growth at drier sites and to a higher tolerance towards drought: higher wood density and cell wall:lumen area ratios of its smaller xylem conduits, lower calculated hydraulic conductivity and more negative Ψ50 values. The BI method is well suitable for determining the wood density in tropical conifers. As a fast and inexpensive method, it may be used for initial screening woody species for their water transport capacity and drought resistance.

In: IAWA Journal
In: IAWA Journal
Author: Alan Dickson

Abstract

A conventional stereo light microscope was used to image polished wood surfaces at cellular resolution over size scales of the growth ring or larger. Bandpass filtering and local area contrast enhancement were used to aid automatic image thresholding and binarisation. An estimate for the location and proportion of cell collapse was introduced based on the distance between uncollapsed cell lumens. Additionally, spatial associations between vessels were determined using a Euclidean distance transform. The analysis of pith to bark cores provided sufficient detail to show significant intra and inter-annual trends in Pinus radiata tracheid dimensions (wall thickness, wall area, and radial widths). These trends were consistent with expectations and in agreement with the literature. Measured cell dimensions may be influenced by cell collapse and deformation as a result of drying. The analysis of air, kiln and oven-dried Eucalyptus nitens showed that cell collapse was highly variable but generally more prominent in the outer third of growth rings. There were significant changes in vessel shape across the growth rings and vessel area was significantly reduced by drying. The technique provides an intermediate step between detailed microscopy and macroscopic imaging that allows spatial analysis at the wood cell level.

In: IAWA Journal
Open Access
In: IAWA Journal

Abstract

The Hibiscus macrophyllus tree is widely planted in Indonesia especially on Java Island. It has several advantages to be developed commercially as a community or plantation forest compared to the famous introduced species Falcataria moluccana and Anthocephalus spp., including faster growth, higher wood density, and better stem morphology (straighter, more rounded, and lesser branches). However, information about the basic properties of this wood grown in plantations is limited. This study aimed to investigate the anatomical properties of H. macrophyllus and their variation at three ages (8, 12 and 16 years old), as well as to predict the mature wood development by using radial variation in fiber length, microfibril angle (MFA), and wood density from pith toward the bark as the indicators. The wood samples were obtained from a community forest area at Ciamis Regency, West Java Province. Furthermore, anatomical characteristics were examined through wood slides following the IAWA List, while fibre and vessel element dimensions were measured through macerated specimens prepared by modified Franklin’s method. The MFA was determined by X-Ray Diffraction, while wood density was measured in line with British Standard 373-57. The results showed that the anatomical structures were not influenced by tree age, except for wood porosity, and fibre and vessel element dimensions. The 16-year-old tree tended to be semi-ring-porous, the younger trees were diffuse-porous, while the fiber and vessel element length, as well as the diameter, were decreased. Meanwhile, the wall thickness was increased. The fibre length, MFA, and wood density were useful indicators for wood maturity that seemed to be developed at about 11 years of age.

In: IAWA Journal

Abstract

Limited investigations have been carried out on the physiological and growth responses of bark to wounding, even though wound periderms play crucial roles in tree defenses. To understand the mechanisms of wound periderm formation, we studied the growth responses and structural changes of wounded bark of three Cryptomeria japonica individuals. We observed the developmental time frame and morphology of wound periderms around mechanically induced wounds in summer. The wound responses included discoloration, lignification, and suberization in tissues present at the time of wounding, followed by wound periderm formation and secondary metabolite deposition. The trees had developed wound periderms approximately 4 weeks after wounding. The wound periderms were within 3 mm in the axial directions and within 1 mm in the lateral directions from the wound surfaces. The distinct patterns of wound periderm formation in the axial and lateral regions resulted from the arrangement and anatomical features of the cells adjacent to the wounds. The wound phellem cells were tangentially narrower and axially shorter in the side and upper/lower regions, respectively, of the wounds. Therefore, the cell division frequencies in the planes parallel to the wound surface may be greater than those in the other directions. Wound reactions in bark might initially be triggered by microenvironmental changes, such as the spread of desiccation, which depends directly on the morphology of phloem cell complexes.

In: IAWA Journal
In: Israel Journal of Plant Sciences

Abstract

A taxonomic list of macro marine algae (seaweeds) described in the literature for the Red Sea during the years 1756–2020 is presented. The list was prepared using existing published studies, local monitoring reports, as well as “grey” or unpublished lists of seaweeds for the area. Altogether, we examined more than 300 publications and compiled more than 900 taxonomic names, of which 576 correspond to valid species, whilst 355 names were considered synonyms for these species. The phylum Chlorophyta (green seaweeds) was represented by 37 currently accepted genera and 133 species (including 74 species synonyms). The phylum Ochrophyta (Phaeophyceae only; brown seaweeds) was represented by 52 genera, 157 species and 99 synonyms; and the phylum Rhodophyta (red seaweeds) by 130 genera, 286 species and 182 synonyms. The brown seaweed Sargassum appears to be a particularly biodiverse genus in the area represented by 58 species and 26 synonyms. Our study shows the inconsistency and lack of long-term taxonomic studies and recent molecular investigations of seaweeds from nearly the whole Red Sea.

In: Israel Journal of Plant Sciences

Abstract

A new species, Syzygium guipingensis sp. nov. (Myrtaceae), is described based on mummified fossil wood from the Miocene Erzitang Formation of Guiping Basin, Guangxi, South China. This species represents the most ancient reliable fossil record of the genus Syzygium in eastern Asia, showing the greatest similarity to the extant species S. buxifolium Hook. et Arnott. Its occurrence in the Miocene is consistent with the diversification age of the Asian lineage within Syzygium as estimated by molecular dating (11.4 Ma). The fossil record of Syzygium suggests that this genus migrated from Australia to eastern Asia in the Miocene, coincidently with the formation of island chains between these continents.

In: IAWA Journal