Long slide holders for microscope stages
ABSTRACT The use of automated techniques for image analysis of microscopic wood specimens together with new procedures for the preparation of stained xylem tissue support the use of quantitative wood anatomy. These techniques and procedures are especially useful in the studies of retrospective analysis of xylem phenology, reaction(s) of trees to stressful conditions of growth, or reconstruction of long-term growth trends. The unresolved technical problems during the digitalization of cross sections from entire increment cores were stabilization and precise shifting of long microscopic specimens onto the optical microscope stage. For this reason, we have developed a long slide holder for mic…
Direct exposure to solar radiation causes radial growth eccentricity at the beginning of the growing season in Robinia pseudoacacia
Abstract Our study investigated the effect of stem temperature increase on xylem formation in Robinia pseudoacacia tree-trunks, caused by direct exposure to solar radiation. It is important to determine factors which may improve the concentricity of deposited wood tissue and intensify xylogenesis because a strong irregularity of wood tissue deposited in the radial direction in mature trees of R. pseudoacacia reduces the commercial value of the wood. Samples of vascular cambium along with adjacent tissues were collected from the southern (illuminated) and northern (shaded) side of tree-trunks growing in the inner and peripheral (thus exposed to direct sunlight) zones of the research plot. Sa…
Geometric analysis of intrusive growth of wood fibres in Robinia pseudoacacia
ABSTRACT All cell types of the secondary xylem arise from the meristematic cells (initials) of the vascular cambium and grow under mechanical constraints emerging from the circular-symmetrical geometry that characterises many tree trunks. The course of intrusive growth of cambial initials has been elucidated, but is yet to be described in the case of xylem fibres. This study explains the geometry of intrusive growth of the secondary xylem fibres in the trunk of Robinia pseudoacacia. Long series of serial semi-thin sections of the vascular cambium and the differentiating secondary xylem were analysed. Since fibres grow in close vicinity to expanding cells of the derivatives of the vascular c…