Conductance in the wood of selected Carboniferous plants

Paleobiology ◽  
1986 ◽  
Vol 12 (3) ◽  
pp. 302-310 ◽  
Author(s):  
Michael A. Cichan
Keyword(s):  
Wood Anatomy ◽  
Growth Habit ◽  
Secondary Xylem ◽  
Middle Part ◽  
Specific Conductance ◽  
Plant Evolution ◽  
Seed Plant ◽  
Fossil Plants ◽  
Tracheary Elements ◽  
Conducting Tissue

Specific conductance was calculated for secondary xylem in seven Carboniferous stem taxa utilizing an equation derived from the Hagen-Poiseuille relation. Arborescent and lianoid representatives of major pteridophytic (Calamitaceae, Lepidodenraceae, Sphenophyllaceae) and gymnospermous (Cordaitaceae, Medullosaceae) groups were examined. In the calamite Arthropitys communis and the seed plant Cordaites (Cordaixylon sp. and Mesoxylon sp.), conductance corresponded approximately to the low end of the range for both extant conifers and angiosperms. A substantially higher conductance was determined for the wood of Arthropitys deltoides, conforming to the high end of the range for conifers and the low-middle part of the range for angiosperms. The highest conductance values were found in Sphenophyllum plurifoliatum, Medullosa noei, and Paralycopodites brevifolius and corresponded to the middle-high portion of the range for vessel-containing angiosperms. This outcome is particularly significant in light of the fact that tracheary elements in the fossils are imperforate. The results indicate that conductance in secondary xylem of some of the most ancient, woody groups was comparable to that in extant plants and that highly effective conducting tissue developed relatively early in plant evolution. Moreover, it is suggested that the general relationship between wood anatomy, growth habit, and ecology demonstrated for living plants can also be extended back in time to include fossil plants.

Distinctive wood anatomy of the root-parasitic family Lennoaceae (Boraginales)

IAWA Journal ◽  
2017 ◽  
Vol 38 (1) ◽  
pp. 3-12
Author(s):  
Sherwin Carlquist ◽  
C. Matt Guilliams
Keyword(s):  
Wood Anatomy ◽  
Secondary Xylem ◽  
High Water ◽  
Tracheary Elements ◽  
Crown Group ◽  
Vessel Lumen ◽  
Vessel Elements ◽  
Desert Areas ◽  
Perforation Plates ◽  
Large Primary

The four species of Lennoaceae have strands of primary plus secondary xylem in a background of starch-rich parenchyma. These strands constitute a cylinder with large primary rays. The wood within these strands is markedly different from that of other families in the crown group of Boraginales such as Cordiaceae and Ehretiaceae, most of which are woody. Lennoaceae differ because they lack fibrous cells (libriform fibers), lack rays within the vascular strands, and have markedly elliptical vessel-to-vessel pits without vestures. Lennoaceae have secondary xylem with short, wide vessel elements with thick walls, horizontally elongate elliptical pits, simple perforation plates much narrower than the vessel lumen; variously uneven vessel wall thickenings; and axial parenchyma. The wood of Lennoaceae shows resemblances to unrelated succulents such as Kalanchoe (Crassulaceae) and Lithops (Aizoaceae). The vessel features also suggest adaptation to high water tensions as root parasites in desert areas, whereas the lack of imperforate tracheary elements may relate to support of the underground stem portions by sand or rock detritus. Habit and ecology are more important in the architecture of lennoaceous xylem than systematic affinities. The four species of Lennoaceae differ from each other in minor xylary features.

Late Permian seed-plant evolution

Science ◽  
2018 ◽  
Vol 362 (6421) ◽  
pp. 1372.17-1374
Author(s):  
Andrew M. Sugden
Keyword(s):  
Plant Evolution ◽  
Late Permian ◽  
Seed Plant

Angiosperm origin and early stages of seed plant evolution deduced from rRNA sequence comparisons

1991 ◽  
Vol 32 (3) ◽  
pp. 253-261 ◽  
Author(s):  
A. V. Troitsky ◽  
Yu. F. Melekhovets ◽  
G. M. Rakhimova ◽  
V. K. Bobrova ◽  
K. M. Valiejo-Roman ◽  
...  
Keyword(s):  
Plant Evolution ◽  
Seed Plant ◽  
Rrna Sequence ◽  
Sequence Comparisons ◽  
Early Stages

scholarly journals Wood functional anatomy of Chiococca alba Hitch. (Rubiaceae) from cerrado

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
João Carlos Ferreira de Melo Junior ◽  
Maick William Amorim ◽  
Gustavo Borda De Oliveira ◽  
Celso Voos Vieira
Keyword(s):  
Wood Anatomy ◽  
Secondary Xylem ◽  
Structural Characteristics ◽  
Functional Anatomy ◽  
Small Diameter ◽  
Great Resistance ◽  
Transport Efficiency ◽  
Anatomical Analysis ◽  
Ecological Aspects ◽  
Perforation Plates

The wood anatomy is able to evidence systematic and ecological aspects associated with the evolution and functionality of the secondary xylem. The present study was carried out using wood of Chiococca alba (Rubiaceae) from cerrado (savannah), to describe its anatomy and to verify if the hydraulic architecture of this species corroborates the theory that postulates the functional tendency that optimizes the transport efficiency associated with safety. The anatomical analysis followed the conventional protocols of wood anatomy. Different indexes of wood hydraulics quantification were calculated, such as solitary vessels index, vessel grouping, conductivity, vessel collapse, theoretical resistance to vessel implosion and mesomorphism. The structural characteristics described for C. alba are in agreement with the general anatomical descriptions for the Rubiaceae family that relate the presence of exclusively solitary vessels and small diameter, simple perforation plates, alternate intervessel pits, apotracheal parenchyma in species with non-septate fibers and narrow and heterogeneous rays. The calculated indexes showed that C. alba is a xerophyte species with great resistance to the collapse of the vessels during the transport of water, little vulnerability to embolism and relative efficiency in the transport when compared to other species of its subfamily (Cinchonoideae) in function of the typical low water availability of the savannah soil.

Introduction

2007 ◽  
Author(s):  
David Beerling
Keyword(s):  
Environmental History ◽  
Charles Darwin ◽  
Earth Science ◽  
Popular Science ◽  
Plant Evolution ◽  
Scientific Investigation ◽  
Fossil Plants ◽  
Terrestrial Plants ◽  
Conventional View ◽  
Plant Life

Charles Darwin (1809–82), the greatest naturalist of all, was fascinated by them, Richard Dawkins all but ignored them. The world, it seems, is divided about the charms of the plant kingdom. The opening quotation of this chapter is from the American popular science author Tom Weller’s witty and provocative 1985 book Science made stupid, and sums up the malaise afflicting those on one side of the great divide. To these folk, plants have an unexceptional evolutionary trajectory leading up to the emergence of our modern floras and play no appreciable role in unravelling Earth’s history. Too often, this view is reiterated, reinforced, in Earth science textbooks, where it is palmed off on the unwary reader as received wisdom. Many such scholarly tomes devote a few pages to Earth’s first green spring, that decisive moment of our past when terrestrial plants turned the continents green. A few graciously give more space—an entire chapter, perhaps—to the progression of plants up the evolutionary ladder from their earliest beginnings through to the appearance of the first forests, the emergence of seed plants, and the blooming of the Earth with the rise of flowering plants. Fewer still recognize plants as important players in the game of life. In this book I argue that Weller’s viewpoint, and the conventional view of textbooks, is now outdated, redundant even, and misguided. The scientific investigation of fossil plants is on the threshold of an exciting new era, a grand synthesis illuminating new chapters in the inseparable stories of plant evolution and Earth’s environmental history. This book is about that new science. It is an endeavour that has emerged unnoticed in the last two decades but which is proving a powerful tool for clearing a path through the dense, sterile thicket of entrenched orthodoxy. It advocates fossils not as the disarticulated remains of ancient plant life gathering dust deep within the basements of museums, but as exciting, dynamic entities brought to life in new ways by the scientific investigation of their living counterparts. The Emerald planet is not a textbook, nor an attempt at describing, blow-by-blow, the detailed evolutionary history of plant life over the ages in a manner accessible to the general reader.

Major Patterns in Botanical Diversity

1999 ◽  
Vol 9 ◽  
pp. 171-186
Author(s):  
Peter R. Crane
Keyword(s):  
Fossil Record ◽  
Pollen Grains ◽  
Terrestrial Ecosystems ◽  
Plant Evolution ◽  
Cambrian Explosion ◽  
Fossil Plants ◽  
Plant Parts ◽  
Plant Fossil ◽  
Public Consciousness ◽  
The Rich

At a time when the popular perception of paleontology is dominated by images of dinosaurs and other spectacular vertebrates, or the mysteries surrounding the Cambrian “explosion” of animal life, it is perhaps not surprising that the rich and informative fossil record of plants has scarcely made an impact on the public consciousness. In reality, as one would expect from those organisms that comprise the bulk of the biological material in terrestrial ecosystems, the fossil record of plants is extensive (Stewart and Rothwell, 1993). Leaves, wood fragments, pollen grains, spores, fruits, seeds and other plant parts are the most common fossils in rocks deposited in ancient flood plains, lakes and many other environments - and they are often exquisitely preserved. This excellent fossil record provides important information about the ecology of ancient terrestrial ecosystems. The quality of the plant fossil record also makes paleobotanical data highly informative about the historical pattern of plant evolution. It is this pattern, and its congruence with patterns in the characters of living and fossil plants — as summarized in a classification — that is the focus of this chapter.

scholarly journals WOOD ANATOMY OF THE VANGUERIEAE (IXOROIDEAERUBIACEAE), WITH SPECIAL EMPHASIS ON SOME GEOFRUTICES

IAWA Journal ◽  
2000 ◽  
Vol 21 (4) ◽  
pp. 443-455 ◽  
Author(s):  
Frederic Lens ◽  
Steven Jansen ◽  
Elmar Robbrecht ◽  
Erik Smets
Keyword(s):  
Pacific Ocean ◽  
Wood Anatomy ◽  
Secondary Xylem ◽  
Vessel Diameter ◽  
Underground Structures ◽  
Axial Parenchyma ◽  
Tropical Asia ◽  
Primary Xylem ◽  
The Pacific ◽  
The Pacific Ocean

The Vanguerieae is a tribe consisting of about 500 species ordered in 27 genera. Although this tribe is mainly represented in Africa and Madagascar, Vanguerieae also occur in tropical Asia, Australia, and the isles of the Pacific Ocean. This study gives a detailed wood anatomical description of 34 species of 15 genera based on LM and SEM observations. The secondary xylem is homogeneous throughout the tribe and fits well into the Ixoroideae s.l. on the basis of fibre-tracheids and diffuse to diffuse-in-aggregates axial parenchyma. The Vanguerieae include numerous geofrutices that are characterised by massive woody branched or unbranched underground parts and slightly ramified unbranched aboveground twigs. The underground structures of geofrutices are not homologous; a central pith is found in three species (Fadogia schmitzii, Pygmaeothamnus zeyheri and Tapiphyllum cinerascens var. laetum), while Fadogiella stigmatoloba shows central primary xylem which is characteristic of roots. Comparison of underground versus aboveground wood shows anatomical differences in vessel diameter and in the quantity of parenchyma and fibres.

Evolution and biogeography ofLyalliaandHectorella(Portulacaceae), geographically isolated sisters from the Southern Hemisphere

2007 ◽  
Vol 19 (4) ◽  
pp. 417-426 ◽  
Author(s):  
Steven J. Wagstaff ◽  
Françoise Hennion
Keyword(s):  
New Zealand ◽  
Southern Hemisphere ◽  
Common Ancestor ◽  
Growth Habit ◽  
Intergenic Spacer ◽  
Plant Evolution ◽  
Late Tertiary ◽  
Close Relationship ◽  
Divergence Estimates ◽  
Transoceanic Dispersal

AbstractThe Southern Hemisphere contains many monotypic taxa, for which phylogenetic relationships are important to illuminate biogeographical history. The monotypic genusLyalliais endemic to the sub-Antarctic Iles Kerguelen. A close relationship with another monotypic taxon, the New Zealand endemicHectorella, was proposed. They share a dense cushion growth habit with small coriaceous leaves that lack stipules. The solitary flowers are bicarpellate with two sepals, 4–5 petals, 3–5 stamens and a bifid style. The fruit is an indehiscent capsule with 1–5 seeds. The flowers ofLyallia kerguelensisare hermaphroditic with four petals and three stamens whereas the flowers ofHectorella caespitosaare female, male or hermaphroditic, with five petals and five stamens.Lyallia kerguelensisis rare on Kerguelen, whereasHectorella caespitosais confined to the South Island of New Zealand. Our phylogenetic analysis oftrnK/matK intergenic spacer andrbcL sequences provides evidence supporting a close relationship betweenLyalliaandHectorella. The two species form a well-supported clade that is nested within the Portulacaceae. Divergence estimates suggest they shared a common ancestor during the late Tertiary long after the fragmentation of Gondwana. Such relationships underscore the importance of transoceanic dispersal and extinctions for plant evolution in the Southern Hemisphere.

Comparative Wood Anatomy of Perennial Shoots of Potentilla (Rosaceae)

IAWA Journal ◽  
2007 ◽  
Vol 28 (4) ◽  
pp. 405-421 ◽  
Author(s):  
A. Stepanova ◽  
E.S. Chavchavadze ◽  
S. Jausen
Keyword(s):  
Wood Anatomy ◽  
Secondary Xylem ◽  
General Trend ◽  
Growth Forms ◽  
Comparative Wood Anatomy

The wood anatomy of perennial shoots of 26 Potentilla speeies was studied using light and scanning eleetron mieroseopy. Secondary xylem of different growth forms was compared. The wood anatomy of perennial shoots of Potentilla speeies with growth forms intermediate between shrubs and herbs (except P. biflora and P. palustris) is similar to the wood anatomy of shrubs. Wood anatomy ofherbaeeous speeies is diverse, and some features have systematie signifieanee. Parenehymati sation and the anatomie al ehanges eorrelated with this proeess appear to be a general trend in the strueture of secondary xylem in rhizomes of herbaeeous Potentilla. This trend may aiso be eommon in rhizome s of other herbaeeous plants, and further studies are required to investigate this.

Sign in / Sign up

Export Citation Format

Share Document