Structural Integrity of Vascular System in Branching Units of Coniferous Shoot

In conifers with spiral phyllotaxis, two numbers: one of the vascular sympodia and the second of cortical resin canals, define the shoot anatomic diameter. This in turn reflects the size and vigor of the apical meristem. Both numbers belong to the mathematical series, associated with the shoot phyllotactic pattern. The number of canals is one step lower in a series than the number of sympodia. The first one, easier to determine, automatically defines the second. Using this protocol and screening the large number of branching shoots of selected conifers, we have discovered strong correlation between orientation of vascular sympodia in the lateral and supporting branches. There was no such correlation with regard to the chiral configurations of phyllotaxis. This finding reveals the presence of special phyllotactic compensation in the case of differences in anatomic diameter of the parental and lateral shoot under the imperative of maintaining the sympodia orientation within one branching unit. Phyllotaxis of the axillary apex is evidently not established at random but adapted to the condition of the subtending axis. The monopodial, regularly branching shoot of conifers is an attractive example of biological system, which is not a sum of independent, iteratively formed units. Rather, it appears to be an entity organized on hierarchically higher level, which emerges from coordination of developmental processes in a population of the units

Mirror Symmetry of Life

Functioning in the Earth gravity field imposes on living organisms a necessity to read directions. The characteristic feature of their bodies, regardless unicellular or multicellular, is axial symmetry. The development of body plan orchestrated by spatiotemporal changes in gene expression patterns is based on formation of the vertical and radial axes. Especially for immobile plants, anchored to the substrate, vertical axis is primary and most important. But also in animals the primary is the axis, which defines the anterior and posterior pole of the embryo. There are many little known chiral processes and structures that are left- or right oriented with respect to this axis. Recent developments indicate the role of intrinsic cell chirality that determines the direction of developmental chiral processes in living organisms. The still enigmatic events in cambia of trees and handedness of phyllotaxis as well as plant living crystals are in focus of the chapter

Geometric parameters of the apical meristem and the quality of phyllotactic patterns in Magnolia flowers

The ratio of primordium size to the meristem size (P/M ratio) is regarded by some geometrical models of phyllotaxis as the parameter, which determines the quality of spiral and whorled patterns of lateral organ arrangement. This assumption was tested on floral meristems in four genets representing four Magnolia taxa: M. × salicifolia, M. stellata, M. denudata and M. acuminata. In successive zones of Magnolia flower, lateral organs are initiated in specific phyllotactic patterns and at specific values of the meristem and primordia sizes. The elements of perianth, usually positioned in three trimerous whorls, are initiated as large primordia on relatively small meristem. The switch in the identity of primordia, from tepals to stamens is accompanied by an abrupt increase in the size of the meristem and decrease in the primordia size. Small values of P/M ratio and frequent occurrence of qualitative transformations of phyllotaxis contribute to the exceptionally rich spectrum of spiral patterns in androecium zone. New spiral patterns emerge when bigger primordia of carpels are initiated on the meristem, which at the same time starts diminishing in size either abruptly (M. × salicifolia, M. stellata, M. acuminata) or slowly (M. denudata). Spiral patterns identified in gynoecia have lower numbers of parastichies than the patterns of androecia and occur in frequencies specific for the genet. Although noted ranges of the meristem and primordia sizes, justify the occurrence of phyllotactic patterns observed in successive zones of Magnolia flower, they do not explain genet-specific frequencies of the patterns observed in gynoecium zone. The lack of straightforward relationship between frequency of the patterns and P/M ratio in gynoecium suggests that more complex geometrical factors or factors of non-geometrical nature are engaged in determination of Magnolia floral phyllotaxis

The significance of γ-and λ-dislocations in transient states of phyllotaxis: how to get more from less – sometimes!

In some plants, developmental changes of phyllotaxis are so frequent that the whole spectrum of phyllotactic patterns becomes available for investigation and thus many unknown subtleties of phyllotaxis come to light. Among these, Magnolia acuminata is the most prominent. In a series of experiments performed in silico with application of a simple geometric model of phyllotaxis, we were able to confront the empirical data on phyllotactic transitions occurring in magnolia flowers with the results of computer simulations. They revealed that in addition to the ratio between the sizes of plant organs, the history of developing pattern was also important, especially for the direction of ontogenetic changes. The parameters of size tolerance and vertical tolerance in positioning a new element in the first available space, brought the effects of simulations closer to the real patterns. They helped especially to resolve the enigma of multiplication of parastichies (γ-dislocations) observed sometimes during determined growth of magnolia floral axes. We conclude that ontogenetic changes in phyllotaxis result mainly from changing sizes of organs in the course of development and that the changes do not always occur with mathematical accuracy

Mechanism of changes in grain inclination in wood produced by storeyed cambium

The changes in cell orientation in the cambium of Entandrophragma producing wood with interlocked type of grain, and in the cambium of 77/io in a spirally girdled stem arc traced through serial tangential sections of wood. In Entandrophragma the changes result from the intrusive growth of a fusiform cell whih repeatedly produces a new pointed tip from one side of the existing tip which disappears. This causes a sort of creeping of cell ends of one storey past those of the adjoining storey. The oppositely directed ends of the cells belonging to one storey creep in opposite directions so that the position of the cell centres remains constant and only the angle between the cells and the stem axis changes. The stratification of short rays in ntandrophragma represents an adaptation to the changes in cell orientation involved in the formation of interlocked grain. The mechanism of changes in grain inclination in 77/ia is intermediate between that based on the creeping of cell ends and that based on pseudotransverse division and intrusive elongation which is known in non-storeyed cambia

Thermal imaging and planimetry evaluation of the results of chronic wounds treatment with hyperbaric oxygen therapy

Background. One of the methods to treat chronic wounds is the use of hyperbaric oxygen (HBO). Objective measurement of the wound surface is an important element in the process of monitoring and predicting the progress of treatment. Objectives. The aim of the study was to evaluate the effect of hyperbaric oxygen therapy (HBOT) on ulcer wound healing in patients with chronic venous insufficiency ulcers and diabetic foot syndrome using thermal imaging and computerized planimetry. Material and methods. During a 3-year period, 284 digital computer planimetry measurements were gathered from 142 patients treated for leg ulcers caused by chronic venous insufficiency and ulcers from diabetic foot syndrome at HBOT Unit of the Dr Stanisław Sakiel Centre for Burns Treatment in Siemianowice Śląskie (Poland). Each patient took 30 HBOT sessions using a Haux multiplace HBO chamber at a pressure of 2.5 atmospheres absolute (ATA). The results of the treatment were monitored using thermovision and computerassisted planimetry measurements performed before and after HBOT. Results. Both groups of patients exhibited a reduction in the surface and perimeter of the wound after HBOT. The treatment effects were also confirmed with thermal imaging. The areas calculated from thermal imaging and planimetry are different but correlated. Conclusions. It seems that a combination of thermal imaging and planimetry may enhance the diagnosis as well as provide the physician with more information about therapy effects

Mechanochemical Polarization of Contiguous Cell Walls Shapes Plant Pavement Cells.

The epidermis of aerial plant organs is thought to be limiting for growth, because it acts as a continuous load-bearing layer, resisting tension. Leaf epidermis contains jigsaw puzzle piece-shaped pavement cells whose shape has been proposed to be a result of subcellular variations in expansion rate that induce local buckling events. Paradoxically, such local compressive buckling should not occur given the tensile stresses across the epidermis. Using computational modeling, we show that the simplest scenario to explain pavement cell shapes within an epidermis under tension must involve mechanical wall heterogeneities across and along the anticlinal pavement cell walls between adjacent cells. Combining genetics, atomic force microscopy, and immunolabeling, we demonstrate that contiguous cell walls indeed exhibit hybrid mechanochemical properties. Such biochemical wall heterogeneities precede wall bending. Altogether, this provides a possible mechanism for the generation of complex plant cell shapes