Scalariform Perforation Plates Research Articles

The variation of perforation plates of vessels in the secondary xylem of Euptelea pleiosperma (Eupteleaceae)

The systematic position of the Eupteleaceae, a monogeneric family including only two species (Euptelea polyandra and E. pleiosperma) and endemic to East Asia, has long been in dispute. This paper deals with the variation of the vessel perforation plates of the secondary xylem of the stem of E. pleiosperma in order to provide new anatomical evidence for a better understanding of the systematic position of this family. The results showed that there were two types of vessels in the secondary xylem of the stem of the species, the tracheid-like vessels and typical vessels. In the tracheid-like vessels, the perforation pits were larger than those in the lateral wall, arranged irregularly and did not exhibit typical morphological features of perforation plates, and the membrane of the perforation pits disappeared completely or partly. In the typical vessels, the perforation plates were of varying forms, falling into several subtypes: reticulate perforation plates (including the foraminate ones); reticulate-scalariform perforation plates in which the perforation pits were both reticulate and scalariform; scalariform perforation plates in which scalariform multi-perforation plates were often observed; the transitional form from scalariform perforation plates to simple perforation ones; and some other forms of perforation plates which could not be referred to any subtypes mentioned above. The membrane remnants could be observed only in the perforation pits of the scalariform perforation plates. Multiple end wall and lateral-wall perforation plates were also observed in the secondary xylem. Based on the present results and a comparison between the perforation plate types in the Eupteleaceae with those of the other members of Ranunculales, we considered that the Eupteleaceae might occupy a basal position in the order. We also inferred that the formation of the perforation plates in E. pleiosperma may have undergone different pathways.

INTERVASCULAR PITTING ACROSS THE ANNUAL RING BOUNDARY IN BETULA PLATYPHYLLA VAR. JAPONICA AND FRAXINUS MANDSHURICA VAR. JAPONICA

The structure of intervascular pits, located at the boundary between the outermost and the second youngest annual rings in Betula platyphylla var. japonica and Fraxinus mandshurica var. japonica was examined by field-emission scanning electron microscopy. Unilaterally compound pits were present in the intervascular common wall at the annual ring boundary in both species. On the outer annual ring side of the unilaterally compound pits, outlines of pit membranes were curved or trifoliate, and each pit aperture was often elongated and curved. The porosity of the intervascular pit membranes differed between the two species. In B. platyphylla var. japonica, microfibrils were loosely packed in the peripheral region of each pit membrane, and openings of up to 300 nm in width were observed. By contrast, microfibrils were densely packed throughout the entire pit membranes in F. mandshurica var. japonica, and no openings perforating the pit membranes entirely were found. In addition, each species exhibited some unique features. In B. platyphylla var. japonica, extensive ethanol-soluble material was detected not only in the intervascular pits but also on scalariform perforation plates. In F. mandshurica var. japonica, we observed fine curly fibrils of unkown chemical composition in the intervascular pit membranes.

Perforation Plate Pit Membrane Remnants in Vessels of Sarraceniaceae: Possible Indicators of Relationship and Ecology

SCHNEIDER, E. AND S. CARLQUIST (Santa Barbara Botanic Garden, 1212 Mission Canyon Road, Santa Barbara, CA 93105). Perforation plate remnants in vessels of Sarraceniaceae: possible indicators of relationships and ecology. J. Torrey Bot. Soc. 131: 1-7. 2004.-All three genera of Sarraceniaceae possess pit membrane remnants in perforations: the abundance of pit membrane remnants parallels the number of bars per perforation plate: most in Heliamphora, fewer in Sarracenia, fewest in Darlingtonia. Heliamphora perforation plates were reported earlier, so Darlingtonia (monotypic) and two species of Sarracenia are considered here. The majority of perforations lack extensive pit membrane remnants, but occasional meshwork-like remnants can be seen at the lateral ends of a number of perforations. Perforations intermediate in size and morphology between perforations and lateral wall pits (pit membranes nearly intact, but containing numerous pores) often occur at upper and lower ends of perforation plates. Pit membrane remnants of this type have been reported in scalariform perforation plates of families thought to be closely related to Sarraceniaceae (Clethraceae, Cyrillaceae, Ericaceae). Species of all four families in which pit membranes are present occur in highly mesic or bog habitats.

OLIGOCENE ANGIOSPERM WOODS FROM NORTHWESTERN BOHEMIA, CZECH REPUBLIC

Two species of fossil angiosperm wood are described from the Oligocene of northwestern Bohemia in the Czech Republic. One specimen from Kadan–Zadní vrch Hill is identified as Cercidiphylloxylon kadanense Prakash et al. Because of its superior preservation, the specimen is designated as an epitype to the original holotype specimen of the species and genus. Cercidiphylloxylon kadanense is known only from the locality of Kadan–Zadní vrch Hill, and it represents the oldest fossil wood of true Cercidiphyllum Sieb. & Zucc. Three other wood specimens from Zichov are attributed to Liquidambaroxylon speciosum Felix. Modern wood of some species of Cercidiphyllum Sieb. & Zucc., Liquidambar L., Altingia Noronha, Corylopsis Sieb. & Zucc., Distylium Sieb. & Zucc., and Hamamelis L. was examined to determine how to distinguish the wood of Cercidiphyllum (Cercidiphyllaceae) from similar woods of Hamamelidaceae. The number of bars in the scalariform perforation plates of the vessels is about 40 in Cercidiphyllum, and about 20 in the Hamamelidaceae. Rays are variable, even at intra-specific level, and are not suitable for distinguishing these woods. These criteria were found to be useful in evaluating affinities of the fossil woods.

Wheeler, E.A. and Manchester, S.R. Woods of the Eocene nut beds flora, Clarno Formation, Oregon, USA. IAWA Journal, Supplement 3

Wheeler, E.A. and Manchester, S.R. Woods of the Eocene nut beds flora, Clarno Formation, Oregon, USA. IAWA Journal, Supplement 3

Stem vascular architecture in the American climbing palm Desmoncus (Arecaceae-Arecoideae-Bactridinae)

Analysis of the stem vasculature of the American climbing palm Desmoncus reveals structural features differing significantly from the Old World rattan genus Calamus. Desmoncus has a more directly continuous vascular system but nevertheless shows a vessel distribution that makes for high hydraulic resistance in the axial xylem. Desmoncus is like Calamus in having a single very wide metaxylem vessel in each central axial bundle and is also without direct vascular contact between protoxylem and metaxylem tracheary elements. However, in Desmoncus the stem vascular bundle system resembles that in tree palms (as has been described in the model palm Rhapis excelsa) in having a continuing axial bundle that branches from each outgoing leaf trace together with a large number of bridge connections between leaf traces and peripheral axial bundles. Resistance to axial water transport is, however, evident in the narrowness of the continuing metaxylem elements in the peripheral stem vascular region. Desmoncus has scalariform perforation plates with few thickening bars in the metaxylem vessels, unlike the simple perforation plates found in Calamus. Thus, Desmoncus shows only limited convergence in stem vascular architecture toward the extreme modifications found in Calamus. This is not unexpected since it is clear that the climbing habit evolved independently in the two genera. © 2003 The Linnean Society of London, Botanical Journal of the Linnean Society, 2003, 142, 243−254.

Vestured Pits: Do They Promote Safer Water Transport?

The distribution of vestured pits in angiosperms is briefly reviewed. In some major clades, the character is of constant occurrence and thus very conservative; in others, it is more variable and apparently subject to both parallel origins and reversible losses. There is a striking correlation between the type of vessel perforation plate and vestured pits. Virtually all taxa with vestured pits have simple perforation plates. This correlation, together with contrasting ecological trends for scalariform perforation plates and vestured pits, has inspired functional hypotheses that vestured pits contribute to hydraulic safety. Whereas scalariform perforations may be instrumental in reducing the effects of freezing-induced embolisms in temperate to boreal and alpine regions, vestured pits seem to be a good candidate to facilitate embolism reversal in xeric and warmer regions with high transpiration rates. The presence of highly lignified structures within the pit chamber may influence hydraulic resistance, decrease vulnerability to cavitation, or help to repair embolism by compartmentalizing or affecting the contact angle of the convex air-water interface within intervessel pits.

Role of Charcoal Analysis for Interpreting Vegetation Change and Paleoclimate in the Miocene Rhine Embayment (Germany)

The potential of fossil wood and charcoal from browncoal deposits as sources of reliable paleoenvironmental information is explored with material from the Lower Rhine Embayment (Germany). The presence of charcoalified material demonstrates proof of natural wildfires in Tertiary mire environments, most probably during, or after periods of increased drainage and drying of surface vegetation and litter. The results presented suggest that sampling from charcoal layers may provide a more statistically reliable data set for study of such environments. Inclusion of taxa recovered from charcoal layers might compensate for the taphonomic and preservational bias of Tertiary lignitic floras based solely on the collection of lignitic wood. These data confirm the hypothesis that, during certain intervals of the Miocene, both monocotyledonous and dicotyledonous angiosperms might have dominated or represented significant portions of the peat-forming vegetation. The importance of palms and shrubby woody taxa, such as ‘Cyrilla’, is particularly striking from new evidence of charcoalified remains. In addition, certain wood anatomical features observed from well preserved lignitic wood and charcoal may be used as indicators of environmentally modulated growth: (1) clear growth rings testify to the existence of a seasonal climate; (2) wide variations in growth ring characters indicate variable environmental conditions; and (3) high incidence of dicotyledonous taxa, with abundant small vessels and scalariform perforation plates, is interpreted as evidence of a mesic environment.

A review of the platanaceous woods from the Eocene paratropical rainforest of south-east England

Small diameter pyritized axes, commonly referred to as ‘twigs’, of fossil platanaceous wood are described from the Lower Eocene London Clay Formation of south-east England. These twigs are characterized by solitary vessels with scalariform perforation plates, opposite intervessel pits, and tall, multiseriate rays that dilate in the phloem region. The wood anatomy supports close relationship to members of extant Platanaceae and the material is placed in the organ genus Plataninium Unger erected for fossil woods with close anatomical similarity to Platanus L. This material supplements the fossil record of platanaceous type wood from the Eocene London Clay and documents the first record of Plataninium decipiens Brett in the twig flora. © 2002 The Linnean Society of London, Botanical Journal of the Linnean Society, 2002, 139, 181‐191.

The earliest fossil evidence of the Hamamelidaceae: Late Cretaceous (Turonian) inflorescences and fruits of Altingioideae

Fossilized pistillate inflorescences, fruits, and pollen grains from the Turonian (∼90 million years before present) of New Jersey are described as a new genus, Microaltingia, in the family Hamamelidaceae. The fossils are remarkably preserved in exceptional detail. Several morphological and anatomical characters suggest affinities with Hamamelidaceae. These include capitate inflorescences, florets with a hypanthium, two-carpellate gynoecia, perigynous flowers, tricolpate reticulate pollen, a three-layered carpel wall, scalariform perforation plates with oblique end walls, and scalariform and opposite/alternate intervascular pitting. The gross morphology of pistillate inflorescences, unisexual flowers, phyllome structure, numerous ovules per carpel, and mode of carpel dehiscence indicate affinities with subfamily Altingioideae, which includes the modern genera Liquidambar and Altingia. Cladistic analysis using a previously published morphological matrix and scoring the fossil for available characters supports the position of the fossil as a sister taxon of modern Altingioideae. Although the fossil exhibits a mosaic of characters found within modern Hamamelidaceae, it is not identical to any modern taxon. Based on cladistic analysis, the fossil appears to be a basal "altingioid" that lacks the derived pollen found in extant Altingioideae and retains the more plesiomorphic tricolpate pollen found in the rest of Hamamelidaceae. The floral characters of the fossils, including phyllomes with stomata, short and straight styles, and small perprolate pollen grains, also indicate the possibility of insect pollination.

Monimiaceae sensu lato, an element of Gondwanan polar forests: Evidence from the late Cretaceous-early tertiary wood flora of Antarctica

Palaeofloristic studies of the Antarctic Peninsula region are important in furthering our understanding of (i) the radiation and rise to ecological dominance of the angiosperms in the Southern Hemisphere during the Late Cretaceous and (ii) the present day disjunct austral vegetation. Investigations of Upper Cretaceous and Early Tertiary sediments of this region yield a rich assemblage of well-preserved fossil dicotyledonous angiosperm wood which provides evidence for the existence, since the Late Cretaceous, of temperate forests similar in composition to those found in present-day southern South America, New Zealand and Australia. This paper describes two previously unrecognised morphotypes, which can be assigned to the Monimiaceae sensu lato, and represents the first record of this family in the wood flora of Antarctica. Specimens belonging to the first fossil morphotype have been assigned to Hedycaryoxylon SÜss (subfamily Monimioideae) because they exhibit anatomical features characteristic of Hedycaryoxylon and extant Hedycarya J.R.Forst. & G.Forst. and Tambourissa Sonn. Characters include diffuse porosity, vessels which are mainly solitary with scalariform perforation plates, opposite to scalariform intervascular pitting, paratracheal parenchyma, septate fibres and tall (>3 mm), wide multiseriate rays with a length: breadth ratio of approximately 1: 4. Specimens belonging to the second morphotype have been assigned to Atherospermoxylon KrÄusel, erected for fossil woods of the Monimiaceae in the tribe Atherospermeae (now Atherospermataceae) in that they exhibit anatomical features similar to Atherospermoxylon and extant Daphnandra Benth., Doryphora Endl. and Laurelia novae-zelandiae A.Cunn. These characters include diffuse to semi-ring porosity, scalariform perforation plates with up to 25 bars, septate fibres, relatively short (<1 mm) rays with a length: breadth ratio of between 1: 4 and 1: 11.

Observations on the vegetative anatomy of Austrobaileya: habital, organographic and phylogenetic conclusions

For the single species of Austrobaileya (Austrobaileyaceae), quantitative and qualitative data are offered on the basis of a mature stem and a root of moderate diameter. Data available hitherto have been based on stems of small to moderate diameter, and roots have not previously been studied. Scanning electron microscope (SEM) photographs are utilized for roots, and show compound starch grains. Roots lack sclerenchyma but have relatively narrow vessels and abundant ray tissue. Recent phylogenies group Austrobaileyaceae with the woody families Illiciaceae, Schisandraceae, and Trimeniaceae (these four may be considered Illiciales), and somewhat less closely with the vesselless families Amborellaceae and Winteraceae and the aquatic families Cambombaceae and Nymphaeaceae. The vessel-bearing woody families above share vessels with scalariform perforation plates; bordered bars on plates; pit membrane remnants present in perforations; lateral wall pitting of vessels mostly alternate and opposite; tracheids and/or septate fibre-tracheids present; axial parenchyma vasicentric (sometimes abaxial); rays Heterogeneous Type I; ethereal oil cells present; stomata paracytic or variants of paracytic. Although comparisons between vessel-bearing and vesselless families must depend on fewer features, Amborellaceae and Winteraceae have no features incompatible with their inclusion in an expanded Illiciales.

Observations on the vegetative anatomy of Austrobaileya: habital, organographic and phylogenetic conclusions

Abstract For the single species of Austrobaileya (Austrobaileyaceae), quantitative and qualitative data are offered on the basis of a mature stem and a root of moderate diameter. Data available hitherto have been based on stems of small to moderate diameter, and roots have not previously been studied. Scanning electron microscope (SEM) photographs are utilized for roots, and show compound starch grains. Roots lack sclerenchyma but have relatively narrow vessels and abundant ray tissue. Recent phylogenies group Austrobaileyaceae with the woody families Illiciaceae, Schisandraceae, and Trimeniaceae (these four may be considered Illiciales), and somewhat less closely with the vesselless families Amborellaceae and Winteraceae and the aquatic families Cambombaceae and Nymphaeaceae. The vessel-bearing woody families above share vessels with scalariform perforation plates; bordered bars on plates; pit membrane remnants present in perforations; lateral wall pitting of vessels mostly alternate and opposite; tracheids and/or septate fibre-tracheids present; axial parenchyma vasicentric (sometimes abaxial); rays Heterogeneous Type I; ethereal oil cells present; stomata paracytic or variants of paracytic. Although comparisons between vessel-bearing and vesselless families must depend on fewer features, Amborellaceae and Winteraceae have no features incompatible with their inclusion in an expanded Illiciales.

WOOD ANATOMY OF SCHEFFLERA AND RELATED TAXA (ARALIACEAE). II. SYSTEMATIC WOOD ANATOMY OF NEW CALEDONIAN SCHEFFLERA

The wood anatomy of 22 of the 26 species of Schefflera occurring in New Caledonia was studied. Only two features (the presence of scalariform perforation plates and scanty paratracheal axial parenchyma) appear to be constant throughout the species examined. The pattern of wood structure diversity was analyzed using PCA; the results generally agree with the current recognition of four groups of species among New Caledonian Schefflera based on macromorphology. Three of these groups (Dizygotheca, “Canacoschefflera” and “Gabriellae”) represent natural assemblages closely related to one another. The fourth group (Schefflera sect. Schefflera) is isolated from the others, as indicated by its very large rays and abundant septate fibres. The occurrence of crystals in chambered cells of axial parenchyma was observed for the first time in Araliaceae. The wood structure of Schefflera plerandroides, previously placed in the segregate genus Octotheca, shows no essential differences from that of the other members of the Dizygotheca group, supporting the hypothesis that polymerous flowers have evolved independently at least twice within the Schefflera alliance.

A revision of the anatomy of Gunneraceae

New studies on the anatomy of the leaf, stem, stolon and root of 17 taxa of Gunnera have revealed several interesting anatomical features. Scalariform perforation plates occur in most vessel elements of stolons and roots, although simple perforation plates are more frequent in the stems of large leafed-species. The leaf surface and internal anatomy have not been studied since the late 19th and early 20th centuries. In this paper, detailed studies of the leaf include features such as marginal and laminar hydathodes, «warts», hair types, and groups of 2–5 palisade-like cells connected to each other by short communicating tubes. The anatomy of Gunnera herteri is described in detail for the first time. Nostoc colonies in the leaf are illustrated.

A revision of the anatomy of Gunneraceae

Abstract New studies on the anatomy of the leaf, stem, stolon and root of 17 taxa of Gunnera have revealed several interesting anatomical features. Scalariform perforation plates occur in most vessel elements of stolons and roots, although simple perforation plates are more frequent in the stems of large leafed-species. The leaf surface and internal anatomy have not been studied since the late 19th and early 20th centuries. In this paper, detailed studies of the leaf include features such as marginal and laminar hydathodes, «warts», hair types, and groups of 2–5 palisade-like cells connected to each other by short communicating tubes. The anatomy of Gunnera herteri is described in detail for the first time. Nostoc colonies in the leaf are illustrated.

The fossil record of Cunoniaceae: new evidence from Late Cretaceous wood of Antarctica?

Fossil angiosperm wood from Upper Cretaceous sediments of Livingston Island and James Ross Island in the northern Antarctic Peninsula region is identified as having the combination of anatomical characters most similar to modern Cunoniaceae. The material is characterised by predominantly solitary vessels, opposite to scalariform intervessel pitting, scalariform perforation plates, heterocellular multiseriate and homocellular uniseriate rays, diffuse axial parenchyma. Anatomically, the specimens conform most closely to the fossil organ genus Weinmannioxylon Petriella which has been placed within the Cunoniaceae. The presence of Weinmannioxylon in Late Cretaceous sediments suggests that taxa within or stem taxa to the Cunoniaceae might have been a notable component of the forest vegetation that covered the Antarctic Peninsula during the Late Mesozoic and may therefore represent the earliest record of this family.

Illicioxylon, an Element of Gondwanan Polar Forests? Late Cretaceous and Early Tertiary Woods of Antarctica

The Late Cretaceous and early Tertiary sediments from the northern Peninsula region of Antarctica yield a rich assemblage of fossil wood with well preserved anatomy. Wood specimens of a previously recognized morphotype are described. The woods are characterized by diffuse porous wood, mainly solitary vessels with long scalariform perforation plates, scalariform and opposite vessel-ray pitting, generally uniseriate and biseriate heterogeneous rays, and tracheids with obvious uniseriate, circulate, bordered pits. These fossil specimens show greatest anatomical similarity to the organ genus Illicioxylon Gottwald and extant members of the Illiciaceae. The occurrence of illiciaceous-like wood in Gondwana suggests that the distribution of this family may have been more widespread in the geological past and that a relatively warm temperate climate prevailed over the northern Peninsula region of Antarctica during the Late Cretaceous and early Cenozoic.

SEM Studies on Vessels in Ferns. 19. Marsilea

Tracheary elements from roots and rhizomes of M. drummondii, M. quadrifolia, and M. vestita supplement the work of other authors by showing features of Marsilea vessels not previously reported or not commonly reported. Pit dimorphism (wide pits lacking pit membranes alternating with narrow pits covered with pit membranes) form perforation plates in some vessel elements. Scalariform perforation plates with perforations like lateral wall pitting in size are com- mon, and have not been previously reported in Marsilea by workers using light microscopy; fur- ther SEM studies may reveal such perforation plates to be more common in the family than pres- ently thought. Circular to oval pits arranged in alternate, opposite, and transition fashion are characteristic of some vessels in the genus, as are tracheary element facets with few or no pits. The occurrence of perforation plates with few bars (found also in xeric and boreal ferns) and simple perforation plates in Marsilea may represent a capability for rapid uptake of water in habitats with relatively short periods of water availability. Marsileaceae have been explored more thoroughly than other fern families for presence and morphology of vessels. Following the initial reports of vessels in roots of Marsilea by White (1961, 1962), Mehra and Soni (1971) confirmed presence of vessels in Marsilea roots but did not find them in rhizomes of the genus. Tewari (1975) reported vessels in roots of Regnellidium. Bhardwaja and Baijal (1977) reported vessels in roots of nine species of Marsilea, but in rhi- zomes of only two Marsilea species. Loyal and Singh (1978) observed vessels in roots of seven species of Marsilea, and also found vessels in the nodal regions where roots and petioles join the rhizome, but not in internodal regions of the rhizome. Bhardwaja and Takker (1979) observed only tracheids in xylem of Pilularia. Details on occurrence of vessels in Marsilea were added by John- son (1986); Sharma (1988) cites the work prior to Johnson's on vessels in Mar- sileaceae, but does not add original observations. Note should be taken that all of the studies cited above were performed with light microscopy. Although vessels with well-defined perforation plates con- sisting of few perforations may be observed with reasonable accuracy with light microscopy, observation of fern vessels with SEM (scanning electron mi- croscopy) seems a procedure that can add more information and is therefore of value. In most of the fern families studied in our papers, we have described vessel elements in which perforation plates are very similar to, or identical to, lateral walls of tracheary elements, and differ in absence of primary walls in the perforations, which are like lateral wall pits in size and shape; the distri- bution of perforations as seen by SEM is also distinctive and diagnostic, and not at all random. We believe SEM is valuable in identifying such probable perforations. In some carefully observed preparations utilizing particular stains, light microscopy has been used to establish presence or absence of primary walls in possible perforation plates in vessel elements. SEM, however,

The first record of fossil atherospermataceous wood from the upper Cretaceous of Antarctica

Fossil wood of the Atherospermataceae from the upper Cretaceous of James Ross Island, Antarctica, is described for the first time and represents the earliest record of this family in the Southern Hemisphere. The specimens are characterised by diffuse porous arrangement of vessels, scalariform perforation plates, scalariform and opposite intervessel pitting and predominantly multiseriate rays which occasionally bear low, uniseriate margins. Despite anatomical conformity at the familial level, the fossil woods are not identical to any one extant genus and have therefore been assigned to the fossil organ genus, Laurelites Nishida, Nishida et Nasa, with which the fossils show greatest similarity.