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Editor: Pieter Baas
At present the study of functional and ecological wood anatomy enjoys a vigorous renaissance and plays a pivotal role in plant and ecosystem biology, plant evolution, and global change research. This book contains a selection of papers presented at the successful meetings of the International Association of Wood Anatomists and the Cost-Action STReESS (Studying Tree Responses to extreme Events: a Synthesis) held in Naples in April 2013.
Four review papers address (1) the hydraulic architecture of the earliest land plants, (2) the general phenomenon of axial conduit tapering in trees, (3) the hydraulic and biomechanical optimization in one of the most important plantation grown tree species, Norway Spruce, and (4) cellular and subcellular changes in the cambium in response to environmental factors. Three papers review or introduce new tools to observe the 3-D structure and functioning of wood, and novel tools for quantitative image analysis in tree ring series. Finally, five papers report original research on environmental effects on wood structure, including studies on plastic responses in European beech, effects of fire or late summer rains on Mediterranean Aleppo Pine, and the potential for using arctic shrubs or tropical deciduous trees in dendrochronological and climatological studies.
Reprinted from IAWA Journal 34 (4), 2013.
Authors: Pieter Baas and Mary Gregory

Anatomy, ultrastructure and development of mucilage and oil cells in the dicotyledons are reviewed, and a bibliography of the records for oil cells is given. In several families normally characterized by oil cells some of the species also have mucilage cells, or the oil cells seem to be “replaced” by mucilage cells. In other taxa intermediates between oil and mucilage cells have been reported in the literature. This poses the question of a possible homology of oil and mucilage cells, despite their very different attributes in the fully mature state. The taxonomic and phylogenetic significance of oil and mucilage cells is briefly discussed. The need for a comparative developmental, ultrastructural and biochemical study of critical taxa is stressed.

In: Israel Journal of Plant Sciences
Authors: MARY GREGORY and PIETER BAAS

The distribution of mucilage cells in vegetative parts of the dicotyledons is reviewed on the basis of an extensive literature study. Mucilage or slime cells occur in 144 families, belonging to 47 orders as defined in Takhtajan's system of classification. Their systematic and diagnostic value at different levels of the taxonomic hierarchy is discussed. Although mucilage cells are generally diagnostic at the species level, variation within genera and families seriously limits the systematic significance in mostphylads. The core families of the Malvales, which are all mucilaginous, constitute an exception at the ordinal level, while in a number of genera, families, and orders the distribution of mucilage cells tends to be associated with natural groups. In most families and orders of the subclass Asteridae, mucilage cells are absent from the vegetative organs. Development, ultrastructure, histochemistry, and distribution of mucilage cells are briefly reviewed. In almost all well documented cases, mucilage is deposited as an additional wall layer by the Golgi apparatus. Except for mucilage associated with raphide crystals, records of vacuolar mucilages are rare in the dicotyledons and merit critical reinvestigation. The functions attributed to mucilage cells in vegetative parts include carbohydrate storage, water storage, reduction of transpiration, protection from intensive radiation by light scattering or reflection, and protection against herbivory. In almost all cases, experimental evidence for any of these functions is lacking.

In: Israel Journal of Plant Sciences
In: Wood Structure in Plant Biology and Ecology

Abstract

Alerce (Fitzroya cupressoides (Mol.) Johnst.) and Guaitecas cypress (Pilgerodendron uviferum (Don) Florin) are two of the three closely-related species of conifers in the Cupressaceae that are endemic to southern Chile and Argentina. Both are listed in Appendix I of the Convention on International Trade in Endangered Species of Fauna and Flora (CITES). The presence or absence of nodular (conspicuously pitted) end walls in the parenchyma cells provide good diagnostic characters to separate the two species wood anatomically, but the latter is sometimes difficult to distinguish. Therefore, a collaborative project was designed to study the chemical-molecular expression of these species by analyzing the heartwood using DART TOFMS (Direct Analysis in Real-Time (DART) Time-of-Flight Mass Spectrometry (TOFMS). This study compares the anatomical features of heartwood for both species and demonstrates that anatomy in conjunction with chemistry can separate them. DART TOFMS analysis combined with PCA was able to unequivocally determine taxonomic source with a statistical certainty of 99%. The mass spectra results obtained from heartwood demonstrated that identification is feasible after a few seconds, using a very small sample. DART TOFMS is a robust tool for reliable species identification and is useful to identify the taxonomic source of finished products or timber that are suspected of being illegally harvested.

In: IAWA Journal