Fossil forms of Amentiferae

Review of the procedures used in determining fossil plant organs indicates that the many Cretaceous records of extant genera of “Amentiferae” based on leaves should be rejected as theoretically unreliable. Palynological data, in combination with some valid megafossil data, indicate that most recognizable members of “Amentiferae” are no older than the later part of the Late Cretaceous. Juglandales appear to be derivatives of the ancient Normapolles complex and unrelated to other “Amentiferae.” A preliminary account of some of the comparative foliar morphology of extant “Amentiferae” indicates that some—particularly Betulaceae and Fagaceae—are closely related to Hamamelidales but that other families—notably Rhoipteleaceae, Juglandaceae, Didymelaceae, and Leitneriaceae—are unrelated to this order.     

Vegetative anatomy of Pachycortnus (Anacardiaceae)

Pachycormus discolor , an arborescent desert perennial endemic to Baja California, has small, pinnately compound, hypostomatic, bifacial leaves produced on short shoots and photosynthetic stem phelloderm covered by exfoliating translucent phellem. Tightly packed laminal palisade cells are filled with tannins and lack chloroplasts. Spongy mesophyll is the major photosynthetic tissue. Leaves possess unicellular trichomes with secondary walls and uniseriate trichomes with glandular heads. Schizogenous resin ducts occur in primary phloem of stems, leaves and roots as well as all living tissues of the bark. Developmental studies reveal that initiation and differentiation of foliar primordia resembles that of other dicotyledons except that tannin cells and secretory ducts arise precociously. Primary vasculature is an open sympodial system with three principal traces diverging toward each foliar primordium. The wood is highly specialized and comprises mostly unlignified cells packed with starch grains. Thick bark is mainly produced as annual layers of secondary phloem marked by a ring of secretory ducts each surrounded by tannin cells. The possible adaptive significance of these unusual anatomical features is discussed.     

Vegetative anatomy of Ophiopogoneae (Convallariaceae)

CUTLER, D. F., 1992. Vegetative anatomy of Ophiopogoneae (Convallariaceae). The vegetative anatomy (particularly leaf) of species of Ophiopogon, Liriope and Peliosanthes is described from observations with light and scanning electron microscopy. A syndrome of leaf characters is present, including epidermal features; hypodermal fibre-like cells; raphides and unusual short, square-ended prismatic crystals arranged in plates; phloem with abundant sclerenchyma and frequent individual strands each composed of a sieve tube element and its associated companion cell; and vascular bundles with unusual orientation, which shows the very close inter-relationship between Ophiopogon and Liriope. Peliosanthes shares the phloem type, hypodermal fibre-like cells and raphides, but is less similar in epidermal characters and vascular bundle orientation. The significance of the unusual phloem type is considered in relation to similar types in other members of the Liliiflorae.     

Vegetative anatomy of subtribe Habenariinae (Orchidaceae)

Leaves of Habenariinae are characterized by anomocytic stomatal apparatuses, homogeneous mesophyll, collateral vascular bundles in a single series, and thin-walled bundle sheath cells. There is no foliar sclerenchyma nor a hypodermis. Cauline cortex consists of thin-walled living cells among which are large and numerous intercellular spaces. The ground tissue is bordered externally by a layer of thick-walled living cells, except in Habenaria repens. Central ground tissue cells are living, and usually thin-walled surrounding intercellular spaces of various dimensions. These are conspicuously large in H. repens. Collateral vascular bundles are scattered across the ground tissue. Sclerenchyma is absent. Absorbing roots are generally velamentous, exodermal dead cells are diin-walled, and passage cells usually have a thickened outer wall. A regular vascular cylinder is present, and vascular tissue is embedded in parenchyma. Root tubers are velamentous, exodermal cells are usually thin-walled, and passage cells frequently have thickened outer walls. Vascular tissue of root tubers is organized into two classes: (1) those with a single vascular cylinder surrounded by a cortex and (2) those with a series of meristeles dispersed throughout the ground tissue. In group (1) cortex is homogeneous either with or without mucilage cells except in Stenoglattis where the cortex is heterogeneous, consisting of water-storage and assimilatory cells, and lacks mucilage cells. In group (2) the ground tissue consists of larger mucilage-containing cells and smaller assimilatory cells.     

Seed morphology and anatomy in someAnnonaceae

Twelve species ofAnnonaceae, namelyAncana sp.,A. stenopetala, Annona cherimola, A. montana, A. muricata, A. squamosa, Bocagea sp.,Bocageopsis canescens, two species ofUnonopsis, Xylopia aromatica, andX. emarginata, were investigated with respect to the morphology and anatomy of the seed. They show the basic structural pattern characteristic of annonaceous seeds: perichalaza, fibrous mesotesta, and rumination developed by both integuments. However, several differential characters, some of them never previously described, were found: All taxa exhibit an additional endotestal mechanical layer which forms the micropylar plug except inAncana. InAncana the plug is built by the inner integument. Aril, sarcotesta and pits on the seed surface are present in some taxa and show different origin and structure. Special anatomical adaptations possibly functioning during germination are described. The results obtained from the investigated taxa are discussed and compared with published data on seed structure inAnnonaceae.     

Floral anatomy and morphology in thePolygalaceae

Floral morphology and anatomy of 15 genera in thePolygalaceae have been studied. The pentamerous origin of the polygalaceous flower is confirmed and shown to apply to all genera in the family. The keel is interpreted as a single petal, and the androecium as of bimeric origin. Vascular structure in the receptacles ofCarpolobia andMonnina subg.Monnina is described in detail, and a compilation of results, focusing on the vascular supply for the androecium and gynoecium, is given for all genera. Based on similarities and differences in vascularization it is concluded that present taxonomy, in particular the tribal system, needs to be reviewed.     

Comparative anatomy and morphology of nectar-producing Melastomataceae

Background and Aims

Most neotropical Melastomataceae have bee-pollinated flowers with poricidal anthers. However, nectar rewards are known to be produced in about 80 species in eight genera from four different tribes. These nectar-producing species are pollinated by both vertebrates and invertebrates.

Methods

The floral morphology and anatomy of 14 species was studied in six genera of nectar-producing Melastomataceae (Blakea, Brachyotum, Charianthus, Huilaea, Meriania and Miconia). Anatomical methods included scanning electron microscopy, and serial sections of paraffin-embedded flowers.

Key Results

All vertebrate-pollinated melastome flowers have petals that do not open completely at anthesis, thus forming a pseudo-tubular corolla, while closely related species that are bee pollinated have rotate or reflexed corollas. In most species, nectar secretion is related to stomatal or epidermal nectaries and not filament slits as previously reported. Moreover, the nectar is probably supplied by large vascular bundles near the release area. Blakea and Huilaea have nectary stomata located upon the dorsal anther connective appendages. Brachyotum also has nectary stomata on the anther connectives, but these are distributed lengthwise along most of the connective. Meriania may release nectar through the anther connective, but has additional nectary stomata on the inner walls of the hypanthium. Miconia has nectary stomata on the ovary apex. Charianthus nectaries were not found, but there is circumstantial evidence that nectar release occurs through the epidermis at the apex of the ovary and the lower portions of the inner wall of the hypanthium.

Conclusions

Nectar release in Melastomataceae is apparently related to nectary stomata and not filament slits. The presence of nectary stomata on stamens and on ovary apices in different lineages suggests that the acquisition of nectaries is a derived condition. Nectary location also supports a derived condition, because location is strongly consistent within each genus, but differs between genera.Key words: Blakea, Brachyotum, Charianthus, Huilaea, Meriania, Melastomataceae, Miconia, nectaries, nectary stomata, pollination     

Studies in the floral morphology and anatomy of nymphaeales

Floral morphology ofBrasenia schreberi Gmel. andCabomba caroliniana A. Gray was observed chiefly from an anatomical point of view. The receptacle ofB. schreberi is rather flat and a vascular plexus is observable in the mature flower. The vasculature in this plexus is so complex taht it is not easy to trace its structure in detail. by observation on small buds, it can be seen that the receptacular vasculature consists of a girdling bundle in the basal area and usually nine receptacular strands from which traces to the petals and stamens branch off. The vasculature in the receptacle is reconstructed and diagramatically shown as though split longitudinally and spread out in one plane. Floral vasculature inCabomba caroliniana is simpler, and is probably related to the smaller number of stamens and carpels. It also has a girdling bundle at the bottom of receptacle and this vasculature is suggested to be derived by simplification from aBrasenia-type vasculature. Evidence from floral anatomy suggests that these two genera are closely related. InNymphaea, a vascular plexus in the receptacle is also observed (Moseley, 1961; Ito 1983). The plexus ofBrasenia andNymphaea are not the same in their construction. Nevertheless, their fundamental floral vasculature is comparable and it is preferable to place them in the same family or same order.     

The morphology and anatomy of the stigma of Petunia hybrida

Summary A mature stigma of Petunia hybrida ready for pollination shows 4-6 large shining drops of the exudate along with numerous smaller ones. A developing style and stigma have a columnar tissue that flares at the top. In the stigma there can be distinguished a secretory and a storage zone. In the former, schizogenous cavities are formed which are filled with the exudate. The mode of formation and secretion of the drop has been studied with light and electron microscope. The nature of reserves has been studied histochemically.The exudation takes place in two stages. In the first stage, the epidermal and papillae cells release out the oily exudate upon rupture of the cuticle. The second phase of exudation begins with anthesis. The exudate from the schizogenous cavities is released between the epidermal cells. There are distinct loci on the stigma surface where more exudate is given out than at other places.

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Zusammenfassung Bei der Durchsicht der einschlägigen Literatur ergab sich, daß die Kenntnisse über die Entwicklungsgeschichte und den Sekretionsmechanismus des Narben-Schleimes äußerst lückenhaft sind, obgleich dieser im Verlauf des Bestäubungs-Vorganges bei vielen Pflanzen eine bedeutende Rolle spielt. Die vorliegende Untersuchung versuchte daher eine detaillierte Einsicht in die Morphologie und Anatomie der Narbe von Petunia hybrida zu geben, da diese Art als Objekt für zahlreiche physiologische Untersuchungen auf dem Gebiet der Befruchtungs-inkompatibilität dient.Die Blüten von Petunia sind zwittrig, zygomorph und fünfzählig. Sie besitzen fünf epipetale Antheren mit drei verschiedenen Filament-Längen; diese öffnen sich zu verschiedenen Zeitpunkten. Die reife Narbe zeigt zum Zeitpunkt der Bestäubung 4-6 große sowie zahlreiche kleinere, transparente Flüssigkeits-Tropfen.Der sich entwickelnde Griffel mit der Narbe besteht aus einem säulenartigen Gewebe, das sich an der Spitze verbreitert. Bei der Narbe kann eine Sekretions-und eine Reservematerial-Zone unterschieden werden. In der Sekretionszone werden schizogen Hohlräume gebildet, die sich mit dem Exsudat füllen. Die Bildung und Sekretion der Narbenflüssigkeit wurde licht-und elektronenmikroskopisch untersucht. Mittels histochemischer Methoden wurden die Substanzen der Reservematerial-Zone näher charakterisiert.Die Freisetzung der Narben-Flüssigkeit findet in zwei Schritten statt: Während der ersten Phase wird das ölige Exsudat von den epidermalen Zellen und den Papillen der Narbe nach Zerreißen der Narben-Cuticula freigesetzt. In der zweiten Phase jedoch tritt das Exsudat aus den schizogenen Hohlräumen durch die Zwischenräume in der Narben-Epidermis aus. Auf der Narben-Oberfläche gibt es Bezirke, welche offensichtlich in reichlicherem Maße Flüssigkeit produzieren als andere Bezirke.

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Dedicated to the memory of the late Prof. P. Maheshwari FRS, our teacher (R. N. K.) and friend (H. F. L.) who read through the Ms in April at Paris, a month before his death.     

Polymorphism and vestigiality: comparative anatomy and morphology of bryozoan avicularia

Avicularia are polymorphic zooids characteristic of cheilostome bryozoans. Avicularia are assumed to have a defensive role yet ascertaining the presence of sensory structures to support this theory has been overlooked. We examine palatal morphology of the avicularia from five species of cheilostome bryozoans and compare the ultrastructural anatomy of the avicularia from two bugulid species from different habitats. SEM analysis revealed an array of palatal morphologies. Small tufts of cilia emerge from the orifice in the palate of the avicularia of Tricellaria catalinensis, Arachnopusia unicornis and Catenicella pseudoelegans. A ciliated vestigial polypide emerges from the orifice in the palate of Rhynchozoon zealandicum and comprises eleven papillae, or vestigial tentacles, seven of which are covered in microvilli. The vestigial polypide of the bird’s head avicularium of the cosmopolitan Bugula flabellata consists of a mass of ciliated and unciliated cells containing numerous granular vesicles. The avicularium of B. flabellata is capable of detecting tactile stimulation by virtue of the tuft of sensory cilia and is proactive in the capture of invertebrate epibionts. In contrast, in the deep-sea Nordgaardia cornucopioides, the vestigial polypide consists of a ciliated vestigial tentacle encased by glandular secretory cells. Avicularia possess structures derived from a feeding autozooid, and we show how the homologous structures have evolved and suggest that avicularia have been modified to carry out a variety of specific functions.     

Leaf morphology and anatomy of transgenic cucumber lines tolerant to downy mildew

The objective of the present paper was to investigate the reason of increased tolerance to the pathogenic fungus Pseudoperonospora cubensis found in transgenic cucumber (Cucumis sativus L.) lines 210 and 212 bearing 35S:cDNA preprothaumatin II gene construct. The tolerance investigation was accomplished by comparing the morphological and anatomical structure of plant leaves. The results obtained demonstrate that leaves of both lines exhibited some anatomical and morphological characteristics (e.g. wax load and composition, cuticle ultrastructure, ultrastructure of secondary wall, arrangement of mesophylll cells) which may be responsible for enhanced tolerance.     

Twig morphology and anatomy of Mediterranean trees and shrubs related to drought tolerance

De Micco V. and Aronne G. 2008. Twig morphology and anatomy of Mediterranean trees and shrubs related to drought tolerance. Bot. Helv. 118: 139 – 148. Woody species populating Mediterranean ecosystems have evolved phenological, physiological and morphological adaptations to summer drought, but their degree of drought tolerance varies, so that different species dominate along gradients from xeric to more mesic environments. In this study, we analysed morpho-anatomical properties of leaves and twigs of eight Mediterranean woody species. To test whether there is a consistent pattern of adaptation to drought, we hypothesised that the rank order of species along the xeric-mesic gradient would be reflected by increasing or decreasing trends in twig properties or in relationships between leaf area and branch size. One-year-old twigs were sampled from plants growing in a common site on the Tresino promontory in southern Italy. Measurements included leaf number and area, branch length and diameter, as well as the relative amounts of pith, xylem and cortex tissues at the basis of branches. All traits varied significantly among species, but none of them correlated with the rank order of species along the xeric-mesic gradient. In addition, the relationship between leaf area and branch size (length or diameter) was not consistently related to the drought tolerance of the species. Inconsistencies could partly be explained by variations in twig anatomy. These results support the view that not single traits, but combinations of morpho-anatomical features influence the overall capability of species to withstand dry conditions. Submitted 12 May 2008; Accepted 24 September 2008 Subject editor: Sabine Güsewell     

Impact of culture vessel ventilation on the anatomy and morphology of micropropagated carnation

Dianthus caryophyllus cv. Nelken was cultured in vitro under different ventilation rates (0.11, 0.21, 0.68 and 0.86 changes h⁻¹). Ventilation modified the anatomical characteristics of shoots and leaves described for plants grown in non-ventilated vessels: the cuticle became thicker, there was a decreased cell size and intracellular space size. Also, there were more photosynthetic and supportive tissues, including thicker cell walls. Increased ventilation promoted in vitro hardening of micropropagated carnation shoots, and pushed the culture-induced phenotype closer to that of ex vitro acclimatized plants. Anatomical variability of in vitro-grown plants was demonstrated to be a consequence of ventilation. This revised version was published online in August 2006 with corrections to the Cover Date.     

Localization,morphology, anatomy and ultrastructure of osmophores in species of Rhamnaceae

Protoplasma - Although the presence of scent was described for several species of Rhamnaceae, localization, morphology and structure of osmophores were unknown. We studied different species of the...     

The southernmost myco-heterotrophic plant, Arachnitis uniflora: root morphology and anatomy

Root morphology and anatomy of the myco-heterotrophic Arachnitis uniflora (Corsiaceae) were studied in relation to their association with a Glomus species (Glomeromycota). The mycorrhizal features were studied in three distinctive stages of development: (i) shoot and flower restricted to a small, underground bud; (ii) shoot and flower bud up to 1.5 cm; and (iii) shoot and flower already withered. The hyphae penetrate through and between the epidermal and exodermal cells; the exodermis and outer cortical cells become colonized in an inter- and intracellular manner, with some coils being formed in these layers. The fungi colonize the middle cortex, where intracellular vesicles in bundles are abundant. Arbuscules are formed profusely at very early stages of development, while in older stages they almost disappear and abundant vesicles are formed. Except for some details, the pattern of root colonization corresponds to a Paris-type. Presence of storage substances (starch and oil) also was recorded. Starch is produced and stored within root cells, mainly in the outer and inner root cortex. In senescent stages, plant and fungal tissues collapse.