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Ye-Ming Cheng, Yu-Fei Wang, Feng-Xiang Liu, Yue-Gao Jin, R. C. Mehrotra, Xiao-Mei Jiang and Cheng-Sen Li

Edited by E.A. Wheeler

ABSTRACT

The Pliocene fluvio-lacustrine sediments of the Yuanmou Basin, Yunnan, near the southeastern part of Qinghai-Tibet Plateau, China, have yielded diverse and abundant assemblages of fossilized mammals and woods. The Yuanmou fossil woods reveal a wood flora with the highest diversity in the Cenozoic wood in China. The woods can play an important role in understanding palaeofloristics and in reconstructing palaeoclimate of southeastern China. In this study, we describe ten angiosperm taxa and three gymnosperm taxa namely: Castanopsis makinoi (Ogura) Suzuki & Terada (Fagaceae), Cedreloxylon cristalliferum Selmeier (Meliaceae), Dalbergioxylon biseriatensis sp. nov. (Fabaceae), Lagerstroemioxylon yuanmouensis Cheng, Li, Jiang & Wang (Lythraceae), Lithocarpoxylon microporosum sp. nov., Lithocarpoxylon sp. (Fagaceae), Paraalbizioxylon sinica sp. nov., P. yunnanensis sp. nov. (Fabaceae), Pterocaryoxylon huxii sp. nov. (Juglandaceae), Zelkova wakimizui (Watari) Watari (Ulmaceae), Abies sp. (Pinaceae), Cephalotaxus sp. (Cephalotaxaceae), and Picea sp. (Pinaceae). Nearest living relative (NLR) comparisons of these taxa, coupled with previously identified taxa, suggest that altitudinal vegetation zones were present in the Yuanmou region during the Pliocene: (i) subtropical evergreen and deciduous mixed broad-leaved forest dominated by Pterocarya/Juglans, Albizia/Acacia, Bischofia and allied taxa at lower elevations, (ii) subtropical evergreen broad-leaved forest dominated by Quercus/Lithocarpus and Castanopsis at middle altitudes of mountains around the basin, and (iii) evergreen coniferous forest of Abies, Picea and other genera at the higher elevations of the mountains. Based on the habits of the NLRs, the prevailing climate was probably humid subtropical and thus differed from the present-day hot and dry climate supporting savanna. It is suggested that subtropical forest was predominant in Yunnan, while tropical rainforest occurred in southwest Asia and India during the same period. The uplift of the mountains near the Qinghai-Tibet plateau in western Yunnan presumably acted as a barrier to block warm and humid air from the Indian Ocean, which influenced the dispersal and distribution of plants.

Cristina I. Nunes, Roberto R. Pujana, Ignacio H. Escapa, María A. Gandolfo and N. Rubén Cúneo

Edited by E. A. Wheeler

ABSTRACT

An angiospermous wood from the Lower Cretaceous (upper Albian) of the Cerro Barcino Formation, Chubut Group, central Patagonia, Argentina, is described. Its estimated minimum diameter is 40 cm and it is significant as the oldest known angiosperm wood for South America.

It has indistinct growth ring boundaries, vessels solitary and in radial multiples, simple perforation plates, alternate intervessel pits, vessel-ray parenchyma pits oval to horizontally elongated, heterocellular rays, non-septate fibres, axial parenchyma absent, and abundant tyloses. Because this Albian wood has non-septate fibres we assign it to Carlquistoxylon, even though it has a general combination of characters similar to that of Paraphyllanthoxylon, which has septate fibres. The number of vessels per radial multiple, vessel tangential diameter and frequency, vessel-ray parenchyma pitting, and absence of axial parenchyma distinguish the fossil described here from the only previously known species of Carlquistoxylon: Carlquistoxylon nacimientense; therefore, a new species is erected. Because of the close similarities between this new specimen and Paraphyllanthoxylon species, comparisons with all the species included in both genera are provided. Systematic affinities for this wood are discussed considering previous discussions for both Paraphyllanthoxylon and Carlquistoxylon affinities. As the oldest described angiosperm wood in South America to date, this specimen provides critical information on the diversity and growth habit of Cretaceous angiosperms from the Southern Hemisphere.

Gayatri Mishra, David A. Collings and Clemens M. Altaner

Edited by Uwe Schmitt

ABSTRACT

Eucalyptus bosistoana F. Muell. is valued for its naturally durable heartwood. As part of an E. bosistoana breeding programme, we have tested the hypothesis that there is a prolonged transition from sapwood to heartwood in young trees, resulting in a wide transition zone. This needs to be considered when assessing trees for heartwood quantity and quality. Heartwood formation was investigated in radial profiles in cores from bark to bark of 6-year-old trees with conventional and confocal microscopy, and with a range of different staining techniques that visualised the physiological changes taking place in the parenchyma cells. Using immunolabelling with antibodies against histone proteins and α-tubulin, histochemical staining using potassium iodide (I3-KI) and fluorescence emission spectral scanning, we demonstrated that in heartwood nuclei, microtubules, reserve materials (starch) and vacuoles were absent. The observations revealed that 6-year-old E. bosistoana trees contained heartwood. The loss of water conductivity by tyloses formation and the death of the parenchyma cells occurred in close proximity resulting in a transition zone of ~1 cm.

Antonio C. F. Barbosa, Gisele R. O. Costa, Veronica Angyalossy, Tássia C. Dos Santos and Marcelo R. Pace

ABSTRACT

Good anatomical sections can only be obtained with a perfectly sharp knife. Permanent steel microtome knives are present in numerous plant anatomy labs and they yield excellent results, with the only caveat that they need to be re-sharpened after use. Automatic knife sharpeners have been especially designed for this purpose, but they require abrasives in their use, which may be expensive and hard to obtain. Here we describe and illustrate in detail an inexpensive, fast, widely accessible technique to sharpen permanent microtome knives using different sandpaper grits. Knives sharpened with this technique have already been in use for over a decade and are suitable for all types of botanical specimens both embedded and unembedded.

Cláudia Fontana, Gonzalo Pérez-de-Lis, Luiz Santini-Junior, Paulo César Botosso, Cristina Nabais, Mario Tomazello-Filho and José Luís Penetra Cerveira Lousada

ABSTRACT

The wood anatomy of Copaifera lucens Dwyer was studied with an emphasis on its growth ring boundaries. Growth rings are visible to the naked eye and demarcated by marginal parenchyma bands and, sometimes, by thick-walled fibers in the latewood. Secretory canals are associated with marginal parenchyma bands, but not all marginal parenchyma bands are associated with canals. Paratracheal parenchyma is vasicentric to lozenge-aliform. Rays are 1–4-seriate, heterocellular and non-storied. Vessels are visible to the naked eye, diffuse, predominantly solitary, some in multiples, sometimes filled with gums. Crystals present. Wood anatomical characteristics of C. lucens are in agreement with those previously reported for other species of Copaifera. In addition to what had already been described for C. lucens, we observed gelatinous fibers, and some bifurcate fibers, and extremely rare clustered vessels. The growth ring boundaries are well-defined in mature wood but less distinctive near the pith. There are also partial and confluent (wedging) rings, which are difficult to classify by anatomy only, but which represent false rings and complicate tree-ring analysis in this species.

Alexei A. Oskolski, Anna V. Stepanova, Luliang Huang and Jianhua Jin

Edited by E.A. Wheeler

ABSTRACT

The taxonomic position of fossil woods suggested to be related to Bischofia is reassessed based on the examination of the wood anatomy of recently collected samples of its two modern species (B. javanica and B. polycarpa). Woods of B. palaeojavanica from the middle Pliocene of India, and B. javanoxyla from the early Miocene of northern Taiwan have features of extant B. javanica. In contrast, the Eocene Bischofia maomingensis (South China) differs from Bischofia in a number of features and we propose a new combination Chadronoxylon maomingensis (Feng et Jin) Oskolski, Stepanova, Huang et Jin. Bischofia palaeojavanica from the latest Cretaceous–earliest Paleocene Deccan Intertrappean Beds, India, and all other pre-Miocene woods assigned to Bischofia differ from extant Bischofia in vessel diameters, vessel element lengths, intervessel pit sizes, position of vessel-ray pits, and/or abundance of sheath cells in rays. Therefore, their generic position must be reconsidered, and there is no reliable record of Bischofia wood older than Miocene.

João Carlos Ferreira de Melo Júnior and Maria Regina Torres Boeger

ATLAS OF VESSEL ELEMENTS

Identification of Asian Timbers

Stephanie Helmling, Andrea Olbrich, Immo Heinz and Gerald Koch

Tatiana V. Tarelkina, Ludmila L. Novitskaya and Nadezhda N. Nikolaeva

Associate-editor Veronica De Micco

ABSTRACT

This study is a continuation of research on the role of sucrose in figured wood formation in temperate trees. Different concentrations of sucrose solutions were administered for 7 weeks to trunk tissues of Betula pendula Roth, Alnus incana (L.) Moench and Populus tremula L. Then xylem anatomy was examined with particular emphasis to the number of vessels and the spatial orientation of xylem elements. In B. pendula and A. incana a high level of exogenous sucrose caused a reduction in the number and size of xylem vessels, even to the point of absence of vessels. Sucrose concentrations of 100 and 200 g l-1 induced the formation of curly grain and anomalous club-shaped rays in xylem of B. pendula. Populus tremula xylem was not significantly altered by the experiment; the xylem anatomy was more seriously affected by wounding than by sucrose. In B. pendula and A. incana the wood formed during the experiment was similar to figured wood of these species. The decrease in the number and size of vessels in the xylem formed during the experiment possibly suggests that high concentrations of sucrose lead to a decline in the level of physiologically active auxin. Changes in the orientation of xylem elements points to a disruption of basipetal auxin transport. Further biochemical and physiological studies are needed to provide more comprehensive understanding of the relationship between sucrose and auxin during the development of figure in wood.