Organization of mature external glands on the trap and other organs of the bladderwortUtricularia monanthos

Summary The mature dome-shaped glands which cover the outer surfaces of the trap, leaves, anchor and runner stolons inU. monanthos are described using conventional and some high voltage transmission electron microscopy. The glands occur as scattered ordinary external glands and as a compact clump of vestibule glands at the entrance to the doorway. Each gland rests on a basal epidermal cell and consists of a single pedestal and terminal cell. Vestibule and leaf glands differ slightly from the other glands mainly in the structure of the outer wall of the terminal cell. Nuclear crystals are prominent and the cytoplasm of the pedestal and terminal cells contains tubular structures usually aggregated near the nucleus. The pedestal cell is a transfer cell with short wall protuberances on the outer wall, conspicuous mitochondria and a heavily impregnated lateral wall.The terminal cell often has an outer wall that is greatly thickened and a protoplast that may degenerate early. In the most developed cells the protoplast remains active for a long period and the outer wall is differentiated into several layers. The outermost layer is cuticularized consisting of an open meshwork of deposits. In leaf glands a local polysaccharide mass is usually developed within the cuticularized region. The inner non-impregnated region of the outer wall may show four layers. In vestibule glands fewer layers are present and the wall shows prominent lamellations. Some ordinary external glands differentiate a sponge-like substructure within the inner wall.The ultrastructure and function of the glands are discussed. We support the concept that mature external glands are responsible for secreting water, with those on traps being particularly active during the resetting of the organ. Our work provides a structural basis for recent suggestions by other workers that the mechanism of secretion probably involves establishing a standing osmotic gradient within the gland.     

Distribution of certain species of utricularia in relation to their habitats in and around Jamshedpur,India

Species of Utricularia grow in nitrogen-deficient soils and low-nitrogen-containing waters. This compells them to adopt to a carnivorous habit which may affect fish production adversely. The chemical characters of the habitats indicate that an acidic medium is essential for their proper growth. Cu, Zn, Mn and Mo are not essential for the growth of these species.     

Ontogeny of the antennal glands in the crayfish Astacus leptodactylus (Crustacea, Decapoda): immunolocalization of Na+,K+-ATPase

The involvement of the antennal urinary glands in the ontogeny of osmoregulatory functions was investigated during the development of Astacus leptodactylus by measurements of hemolymph and urine osmolality in juvenile and adult crayfish and by the immunodetection of the enzyme Na⁺,K⁺-ATPase. In stage II juveniles, 1-year-old juveniles, and adults, all of which were maintained in freshwater, urine was significantly hypotonic to hemolymph. In adults, chloride and sodium concentrations were much lower in urine than in hemolymph. During embryonic development, Na⁺,K⁺-ATPase was detected by immunocytochemistry in ionocytes lining the tubule and the bladder, at an eye index (EI) of 220–250 m, and in the labyrinth, at EI 350 m. In all regions, immunofluorescence was mainly located at the basolateral side of the cells. No immunofluorescence was detected at any stage in the coelomosac. In late embryonic stages (EI 410–440 m), in stage I juveniles, and in adults, strong positive immunofluorescence was found from the labyrinth up to and including the bladder. These results show that, as early as hatching, juvenile crayfish are able to produce dilute urine hypotonic to hemolymph. This ability originates from the presence of Na⁺,K⁺-ATPase in ion-transporting cells located in the labyrinth, the tubule, and the bladder of the antennal glands and constitutes one of the main adaptations of crayfish to freshwater.We thank the University of Tarbiat Modarres and Ministry of Science, Research and Technology, Islamic Republic of Iran for financial aid and support. Special thanks are also due to the Société Française dExportation des Ressources Educatives (SFERE) for the scholarship to S.K.     

Ultrastructural ontogeny of leaf cavity trichomes inAzolla implies a functional role in metabolite exchange

Summary Anabaena azollae is associated with two types of multicellular epidermal trichomes inAzolla leaf cavities, the simple and branched hairs. The observation of transfer cell ultrastructure in some hair cells led to speculation that the cavity hairs might participate in metabolite exchange between the symbionts. The developmental ontogeny of cavity trichomes is described here, using transmission electron microscopy, with a goal of improving our understanding of possible functions of these structures in the symbiosis. The observations have established that all cells of simple and branched hairs develop the structural characteristics of transfer cells, but not simultaneously. Rather, there is an acropetal succession of transfer cell ultrastructure beginning in terminal cells, moving to body cells where present, and ending in stalk cells. The transfer cell stage is followed immediately by senescence in all hair cells. The timing of transfer cell differentiation, considered together with information from other studies, suggests that branched hairs may be involved in exchange of fixed nitrogen between the symbionts, while simple hairs may participate in exchange of fixed carbon fromAzolla toAnabaena. Contribution no. 869 from the Battelle-C. F. Kettering Research Laboratory.     

Ontogeny of the antennal glands in the crayfish Astacus leptodactylus (Crustacea, Decapoda): anatomical and cell differentiation

The ontogeny of the antennal glands was studied during the embryonic and post-embryonic development of Astacus leptodactylus. The future glands arising from undifferentiated columnar cells were detectable at the metanauplius stage EI 150 m (EI: eye index; approximately 440 m at hatching). The tubule and labyrinth differentiated in embryos at EI 190 m, and the bladder and coelomosac at EI 250 m. At EI 350 m, the tubule lengthened and divided into proximal and distal sub-regions. In later stages, the gland retained the same morpho-anatomy but the differentiation and size of each part increased. The cells of the coelomosac displayed the cytological features of podocytes in late embryonic development at EI 440 m. Only small apical microvilli and a few mitochondria were observable in the labyrinth cells at EI 250 m; by EI 440 m, these cells presented well-shaped apical microvilli, formed bodies, basal infoldings and mitochondria. In the cells of the tubules and bladder, mitochondria and basal infoldings occurred at EI 440 m and EI 250 m, respectively. The differentiation of the tubules and bladder cells suggested that they were involved in active transport at EI 440 m. Following hatching, the differentiation of the cells and the size of the glands increased. The ontogeny of the antennal glands thus starts in early embryos, the specific cellular functional features being differentiated in the various parts of the glands by EI 440 m. The antennal glands are probably functional just before hatching, i.e., before the juveniles are confronted with the low osmolality of freshwater.Thanks are due to the University of Tarbiat Modarres and Ministry of Science, Research and Technology, Islamic Republic of Iran, for financial aid and support. Special thanks are also extended to the Société Française dExportation des Ressources Educatives (SFERE) for a scholarship to S.K.     

Development of serous cutaneous glands in Scinax nasica (Anura,Hylidae): patterns of poison biosynthesis and maturation in comparison with larval glands in specimens of other families

We examined the development of serous (poison) cutaneous glands in larval and juvenile Scinax nasica (Hylidae) at the ultrastructural level. We describe the biosynthesis and maturation of the cutaneous poison in comparison with the corresponding processes in representatives of Discoglossidae, Leptodactylidae, Pelobatidae and Pipidae. Serous biosynthesis in S. nasica starts in discrete adenoblasts and continues in the syncytial secretory unit. Biosynthetic processes involve rough endoplasmic reticulum and the Golgi apparatus, that releases membrane-bounded material, varying from fine grained to flocculent. During the post-Golgian secretory phase, this material undergoes initial maturation, and two products are formed: dense granules and larger vesicles holding a thin substance that will later be structured into a three-dimensional, honeycomb-like net. Both the secretory granules and vesicles change into glomerular-like aggregates of bowed, rod-shaped subunits (modules). In adult frogs, formation of dense granules is bypassed. The modular granule substructure seems to be related to the merocrine release of small amounts of poison, involved in regulating skin homeostasis. Comparison with maturational changes in larval glands of species representing four anuran families discloses similar patterns in the Leptodactylidae, but production of opaque homogeneous granules occurs in the Discoglossidae, clear vesicles in the Pelobatidae and aggregates of dense bars in the Pipidae.     

Ontogeny,function and evolution of extreme floral construction inMonimiaceae

In at least 4 genera of theMonimiaceae (Tambourissa, Wilkiea, Kibara, Hennecartia) extremely specialized flowers with a hyperstigma occur, i.e. a secretory zone in the narrow entrance of the floral cup. The mucilaginous secretion of the hyperstigma and of the carpels produces a transmitting medium for pollen tubes continuous from the mouth of the floral cup to the ovules. As to their floral morphology, the two extreme types,Hortonia andTambourissa, are connected gradually by various other genera. Possible evolutionary trends and systematic problems are outlined.     

Ontogeny of in vitro rooting processes in Eucalyptus globulus

Summary In the present work, histological changes observed at the base of Eucalyptus globulus shoots in in vitro culture are described. Shoots were placed on solidified Murashige and Skoog medium containing half the original salt concentration, the complete vitamin composition, 9.8 μM indolebutyric acid (IBA), and 30 gI⁻¹ agar, and were incubated in the dark for the first 7 d, followed by a 16-h photoperiod. In vitro-generated roots could be originated either from old vascular tissue or from newly formed xylem. The influence of the preexistent tissues on the neoformation process appeared to be varied. The medulla did not intervene directly, although there were abundant cellular divisions in response to the induction medium. On the other hand, the interruptions observed in the vascular cylinder of the stem suggested an influence of the interfascicular parenchyma, and therefore the medulla could have participated in the differentiation process. However, the cortical parenchyma showed most of the changes that lead to the formation of adventitious roots of E. globulus growing in vitro. Histological analysis suggests that vascular rays can also be formed in direct contact with the central cylinder of the stem, although they mainly originate from the cortical parenchyma.     

A new species of <Emphasis Type="Italic">Utricularia</Emphasis> (Lentibulariaceae) from Guerrero,Mexico

Utricularia regia is described and illustrated. It occurs in the Sierra Madre del Sur region of Guerrero, Mexico, and belongs to section Psyllosperma; a key to differentiate the species of sect. Psyllosperma is included. The new species is similar to Utricularia hintonii and U. petersoniae, from which it differs in the unusual division of the upper lip of the corolla into four lobes and its peculiar coloration pattern. A table comparing the differences among these three species is presented. Utricularia regia adds a new, narrowly endemic species to the flora of Guerrero, Mexico.

---

Resumen  Se describe e ilustra como especie nueva para la ciencia a Utricularia regia a partir de ejemplares procedentes del estado de Guerrero, México. La nueva especie se ubica en la sección Psyllosperma y está mejor relacionada con Utricularia hintonii y U. petersoniae; de las que se diferencia por la división del labio superior de la corola en cuatro lóbulos y por su peculiar coloración; se presenta una tabla en la que se comparan más ampliamente estas tres especies y se incluye también una clave para diferenciar las especies de la sección Psyllosperma. Utricularia regia agrega un elemento endémico más a la flora de Guerrero y de México.

     

Ontogeny of prey attack behaviour in larvae and juveniles of three European cyprinids

Synopsis The ontogenetic change in time costs of prey attacks as well as the change in capture efficiency for representative cladoceran and cyclopoid prey was investigated in roach, Rutilus rutilus, bleak, Alburnus alburnus, and blue bream, Abramis ballerus. Video recordings were used for measuring the timing of attacks, whereas capture efficiencies were determined by direct observation. Decreases in the time cost of attacks reflect the decreasing importance of prey fixation during growth of the fish. No differences in capture efficiencies were found among the three cyprinid species, indicating that attack behaviour is unlikely to function as a basic mechanism leading to differences in prey selectivity among the investigated species. Increasing capture efficiency during early development may lead to increasing selectivity for cyclopoid prey in the field.     

Ontogeny of intruding non-periplasmodial tapetum in the wild chicory,Cichorium intybus (Compositae)

The tapetal development ofCichorium intybus L. is investigated using LM and TEM and discussed in relation to the development in other species. During the second meiotic division the tapetal cells become binucleate and lose their cell walls. They intrude the loculus at the time of microspore release from the meiotic callose walls, which means that a locular cavity is never present in this species. During pollen development they tightly junct the exine, especially near the tips of the spines. During the two-celled pollen grain stage they degenerate and most of their content turns into pollenkitt. Until anther dehiscence they keep their individuality, which means that these intruding tapetal cells never fuse to form a periplasmodium. The ultrastructural cytoplasmatic changes during this development are discussed in relation to possible functions.     

<Emphasis Type="Italic">Utricularia rostrata</Emphasis> (Lentibulariaceae), a new species from the Chapada Diamantina,Brazil

Summary   Utricularia rostrata A. Fleischm. & Rivadavia (Lentibulariaceae) is described from the Chapada Diamantina highlands in Bahia state, north-eastern Brazil. The morphological characteristics which distinguish this new species are discussed, together with its distribution and ecology.     

Amplification of inter-symbiont surface by root epidermal transfer cells in thePisonia mycorrhiza

Summary Cells of the root epidermis ofPisonia grandis R. Br. at the interface with the mycorrhizal fungus are modified as transfer cells. The length of wall profile in transverse section is increased 1.7-fold by the wall ingrowths, on average, over the outer tangential wall and the outer third of the radial walls; this corresponds to a 1.3—fold increase in wall profile length over the whole cell. These increases in length of wall profile approximate—slightly underestimating-the amplification of surface area of the epidermal cells that results from the ingrowths. The surface area between the symbionts in thePisonia mycorrhiza is less amplified than in classical ectomycorrhizas with a Hartig net: this may be functionally adequate because of the extremely high nutrient status of theP. grandis habitat.     

Ontogeny of the translator inAsclepiadaceae s.str.

The ontogeny of the translator is analysed inFockea edulis, Pachycarpus dealbatus, andCalotropis procera. The three species show a similar basic pattern in the construction of the corpusculum. Each side wall consists of two originally separate flanks. In the primitive state (Fockea), these flanks remain separate throughout their development, only the two inner flanks fuse along their base. In the derived state, the two flanks on each side fuse to form solid side walls, and the corpusculum develops a floor by additional secretion. The primitive state of divided flanks is recapitulated in early ontogeny. InFockea, the pollinia are attached apically and dorsally to the outer flanks by means of unmoulded adhesive material; in more advanced translators, caudicles are inserted as new elements between the outer flanks and the pollinia. The caudicles are attached to the lower part of the corpusculum. Within the four tribes of the family, many species have retained parts of the primitive structure in their corpuscula. Flanks divided in the lower part of the corpusculum and caudicles attached dorsally to the outer flanks seem to be common inMarsdenieae andStapelieae. InAsclepiadeae andGonolobeae the side walls are solid throughout the length of the corpusculum. — The question of cellular mechanisms underlying the formation of the translator is discussed. In all probability, the main factor responsible for the complex structure of the corpusculum is a differential secretory activity of the glandular field. This, in turn, points to differential genetic activity as a regulating factor of the ontogeny of the translator.     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.     

Cuticle development and ultrastructure: evidence for a procuticle of high osmium affinity

Transmission electron microscopy was used to investigate the development and ultrastructure of the cuticles of the bladder primordium and other parts of Utricularia, the stem of Cuscuta gronovii, and the leaves of Athanasia parviflora. In all materials investigated, except the apical meristem of Cassytha pubescens, the first-formed cuticle, named the procuticle, was very electron dense and apparently amorphous in texture. Later, the procuticle changed its ultrastructural appearance: in all species having a procuticle it lost much of its electron density. Simultaneously, it developed into a lamellar structure in U. lateriflora and Cuscuta, and became part of a lamellar cuticle proper. In U. sandersonii and Athanasia the procuticle generally remained without visible structure. The velum of the pavement epithelium of Utricularia is considered to be a slightly modified procuticle which has become loosened from the epithelial cells and stretched.     

Prey spectra of aquatic Utricularia species (Lentibulariaceae) in northeastern Germany: The role of planktonic algae

The carnivorous bladderworts (Utricularia) possess complicated suction traps. Remarkably, information on the prey trapped is relatively sparse. We have conducted a detailed survey on the prey spectra found in traps of selected aquatic bladderworts (U. australis, U. vulgaris) occurring in ponds in northeastern Germany. A close examination of more than 200 traps revealed cladocerans, copepods, rotiferas, ciliates and insect larvae as being common prey.Of particular interest was the considerable amount of phytoplankton (i.e. algae, cyanobacteria) found in the traps. In total, more than 160 algae species (among others, Kirchneriella lunaris, Scenedesmus quadricauda and S. acuminatus) belonging to more than 50 genera were present, with Chlorophyceae being dominant. The role of the vegetarian diet for nutrient supply of bladderworts is discussed.     

The influence of prey behaviour on prey selection of the carnivorous plant Utricularia vulgaris

The mechanisms underlying differential prey selection of two microcrustaceans by the common bladderwort (Utricularia vulgaris) were studied in the laboratory. Functional response experiments with single prey showed that Utricularia had a higher attack rate coefficient and a longer handling time coefficient with the cladoceran Polyphemus pediculus than with the cyclopoid copepod Eucyclops serrulatus. Observation of predation rate, defined as number of prey eaten per unit time, from direct behavioural observation on single prey species, showed a higher predation rate with Polyphemus than on Eucyclops, at low prey densities. The opposite pattern was found at high prey density. When the two prey were presented simultaneously to the predator, Eucyclops was preferred over Polyphemus. Results from the situation with two prey and some of the results from the direct behavioural observations support field data on the diet of Utricularia, which shows that cyclopoid copepods are selected more frequently than Polyphemus.     

Responses to iron deficiency in Arabidopsis thaliana: The Turbo iron reductase does not depend on the formation of root hairs and transfer cells

Arabidopsis thaliana (L.) Heynh. Columbia wild type and a root hair-less mutant RM57 were grown on iron-containing and iron-deficient nutrient solutions. In both genotypes, ferric chelate reductase (FCR) of intact roots was induced upon iron deficiency and followed a Michaelis-Menten kinetic with a K _m of 45 and 54 M Fe^III-EDTA and a V _max of 42 and 33 nmol Fe²⁺·(g FW)^–1·min^–1 for the wild type and the mutant, respectively. The pH optimum for the reaction was around pH 5.5. The approximately four fold stimulation of FCR activity was independent of formation of root hairs and/or transfer cells induced by iron deficiency. Iron-deficiency-induced chlorosis and the development of a rigid root habit disappeared when ferric chelate was applied to the leaves, while FCR activity remained unchanged. The time course of the responses to iron deficiency showed that morphological and physiological responses were controlled separately.Abbreviations FCR ferric chelate reductase - FW fresh weight Thanks are due to Klaas Sjollema (Department of Electronmicroscopy, University of Groningen, The Netherlands) for help with the electron microscopy sample preparation and especially to Dr. Uwe Santore (Heinrich-Heine-University for electron microscopy. This work was supported by the SCIENCE programm of the European community; P.R.M.) and a Personal Research Grant by the Ministerium für Wissenschaft und Forschung of Nordrhein-Westfalen (P.R.M.) and last, not least by the productive discussions in ECOTRANS B.V.