This second edition of the conifer book PINES is an amended and updated version of the first edition, which sold out in 2002. The scope and structure of the book have been maintained. It includes several taxonomic changes and presents a new chapter on phylogeny. Conservation aspects have been added. The book contains a total of 92 drawings and 103 distribution maps.

Pines. Drawings and Descriptions of the Genus Pinus

Paleobotany: The Biology and Evolution of Fossil Plants

The hormone abscisic acid (ABA) plays a critical role in enhancing plant survival during water deficit. Recent molecular evidence suggests that ABA is synthesized in the phloem companion cells and guard cells. However, the nature of cell turgor and water status in these two cell types cannot easily account for the rapid, water status-triggered ABA biosynthesis observed in leaves. Here, we utilize the unique foliar anatomies of an angiosperm (Hakea lissosperma) and four conifer species (Saxegothaea conspicua, Podocarpus latifolius, Cephalotaxus harringtonii, and Amentotaxus formosana) in which the mesophyll can be isolated from the vascular tissue to identify the main site of ABA biosynthesis in water-stressed leaves. In all five species tested, considerable ABA biosynthesis occurred in mesophyll tissue that had been separated from vascular tissue. In addition, the removal of the epidermis from the mesophyll in two conifer species had no impact on the observed increase in ABA levels under water deficit. Our results suggest that mesophyll cells are the predominant location of water deficit-triggered ABA biosynthesis in the leaf.

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Mesophyll Cells Are the Main Site of Abscisic Acid Biosynthesis in Water-Stressed Leaves

https://repositorio.ufrn.br/bitstream/123456789/29884/1/EnvironmentalBiophysicalControls_LIMA_2020.pdf

Environmental and biophysical controls of evapotranspiration from Seasonally Dry Tropical Forests (Caatinga) in the Brazilian Semiarid

Pinaceae. Drawings and Descriptions of the Genera Abies, Cedrus, Pseudolarix, Keteleeria, Nothotsuga, Tsuga, Cathaya, Pseudotsuga, Larix and Picea.

The comparative study on leaf anatomy and stomata structures of six genera of Taxaceae s. l. was conducted. Leaf anatomical structures were very comparable to each other in tissue shape and their arrangements. Taxus, Austrotaxus, and Pseudotaxus have no foliar resin canal, whereas Amentotaxus, Cephalotaxus, and Torreya have a single resin canal located below the vascular bundle. Among them, Torreya was unique with thick-walled, almost round sclerenchymatous epidermal cells. In addition, Amentotaxus and Torreya were comprised of some fiber cells around the vascular bundle. Also, Amentotaxus resembled Cephalotaxus harringtonia and its var. nana because they have discontinuous fibrous hypodermis. However, C. fortunei lacked the same kind of cells. Stomata were arranged in two stomatal bands separated by a mid-vein. The most unique stomatal structure was of Taxus with papillose accessory cells forming stomatal apparatus and of Torreya with deeply seated stomata covered with a special filament structure. Some morphological and molecular studies have already been discussed for the alternative classification of taxad genera into different minor families. The present study is also similar to these hypotheses because each genus has their own individuality in anatomical structure and stomata morphology. In conclusion, these differences in leaf and stomata morphology neither strongly support the two tribes in Taxaceae nor fairly recognize the monogeneric family, Cephalotaxaceae. Rather, it might support an alternative classification of taxad genera in different minor families or a single family Taxaceae including Cephalotaxus. In this study, we would prefer the latter one because there is no clear reason to separate Cephalotaxus from the rest genera of Taxaceae. Therefore, Taxaceae should be redefined with broad circumscriptions including Cephalotaxus.

Leaf anatomy and its implications for phylogenetic relationships in Taxaceae s . l .

A number of conifer species are still lacking anatomical data, which is significant because morphological and anatomical data are essential for systematic study. Leaf anatomy was studied in selected species of Abiesand Piceausing light and scanning electron microscopy. Both genera were found to have typical coniferous and highly xerophytic leaves with sunken stomata and an epidermis covered by a thick cuticle. In the genus Abies, species can be differentiated by the nature of the lignified hypodermis and the number and position of resin ducts. Abies firma and A. holophylla have a continuous hypodermis whereas in A. koreana and A. nephrolepis the hypodermis is discontinuous and represented by isolated cells or groups of four or five cells. On the other hand, in Picea leaf shape, stomata arrangement, and number, position, and nature of resin ducts are the key features for species differentiation. Picea jezoensis has a flattened leaf with stomata distributed on the adaxial surface whereas P. abies and P. koraiensis have a rectangular leaf with stomata found on surfaces.

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Comparative leaf anatomy of some species of Abies and Picea (Pinaceae)

Comparative wood anatomy of Taxaceae s.l. was examined to elucidate the differences in wood features among genera. In total, 25 samples, comprising three varieties and seven species from five genera (Pseudotaxus was not included), were examined. Sliding microtome, wood maceration and scanning electron microscopy methods were used for the study. The growth rings are well developed and early and late wood are distinguishable in a cross-section. In general, there is remarkable uniformity in the characteristics of the five genera of Taxaceae, although some differences in quantitative traits were found. Wood of Taxaceae s.l. differs from that of most conifers by having helical thickening in the tracheid inner walls, with the exception of Austrotaxus spicata R.H.Compton. All genera are characterised by the absence of resin canals, predominantly uniseriate pits on the radial wall of the axial tracheids, and the presence of pits on the tangential walls of the axial tracheids. The rays are composed solely of parenchyma cells and are uniseriate (occasionally biseriate in Torreya nucifera (L.) Siebold et Zucc.), with a height of 1–22 cells. The genus Taxus shares more characteristics with Torreya than with Amentotaxus, Austrotaxus and Cephalotaxus. Correspondingly, Amentotaxus and Cephalotaxus resemble each other, marked by the presence of either diffuse or sparse axial parenchyma with nodulated transverse walls. Austrotaxus spicata is the sole species that lacks helical thickenings in the tracheid walls and has sparse axial parenchyma with smooth transverse walls. These two features, namely, the absence of helical thickenings and axial parenchyma with smooth transverse walls, are plesiomorphic and might be considered a more primitive character in wood anatomy. Among the other four genera, Amentotaxus appears to have an annular type of wall thickening that could be considered plesiomorphic to the spiral thickenings found in Taxus, Torreya and Cephalotaxus.

https://bioone.org/journals/Australian-Systematic-Botany/volume-28/issue-2%e2%80%933/SB14050/Comparative-wood-anatomy-of-Taxaceae/10.1071/SB14050.pdf

Comparative wood anatomy of Taxaceae

Comprehensive comparative anatomy of Pinus leaves was carried out. Some anatomical features were found to be quite useful and supported the classification of genus to subgenus and section level. The number of needles per fascicle, number of vascular bundles, position of resin ducts, shape of leaf in cross section, and distribution of stomata on the leaf surface showed remarkable variation between different species and facilitated the classification of Pinus into minor groups: subgenus, section, and subsection. The members of subgenus Pinus had two vascular bundles whereas members of subgenus Strobus had only one vascular bundle. The position of resin ducts was more consistent in subgenus Strobus than in subgenus Pinus. Interestingly, the species of subsection Strobus included in this study lacked stomata on the abaxial surface. The results indicate that the number of needles per fascicle and needle size are inversely related, and more importantly that a greater numbers of needles per fascicle lead to a more angular shape.

Comparative leaf anatomy of native and cultivated Pinus (Pinaceae) in Korea: implication for the subgeneric classification

The inconsistent relationship between the monogeneric family Cephalotaxaceae and Taxaceae was discussed and the possibility of merging Cephalotaxus within Taxaceae was also reviewed. Our previous reports (cladistics analysis, leaf anatomy and wood anatomy of Taxaceae s.l.) did not find a feasible reason to create a distinction between Cephalotaxus and other Taxad genera (Taxus, Pseudotaxus, Amentotaxus, Torreya and, Austrotaxus) and thus argued for a broader concept of Taxaceae with Cephalotaxus. The monophyly of Taxaceae including Cephalotaxus is described in various contemporary molecular studies, and some of them are in support of the single large family Taxaceae with six genera. Although additional comprehensive studies in the future may perhaps weaken the precise association between Cephalotaxaceae and other Taxad genera, on the basis of recent corroborations, at this moment Taxaceae should be redefined with broad circumscriptions, including Cephalotaxus.

/pdf/inclusion-of-cephalotaxus-in-taxaceae-evidence-from-4ez7lu21wc.pdf

Chunghee Lee

Papers

Leaf anatomy and its implications for phylogenetic relationships in Taxaceae s . l .

Comparative leaf anatomy of some species of Abies and Picea (Pinaceae)

Comparative wood anatomy of Taxaceae

Comparative leaf anatomy of native and cultivated Pinus (Pinaceae) in Korea: implication for the subgeneric classification

Inclusion of Cephalotaxus in Taxaceae: Evidence from morphology and anatomy