Complex tendril branching in two species of Parthenocissus: implications for the vitaceous shoot architecture

2003 ◽  
Vol 81 (6) ◽  
pp. 587-597 ◽  
Author(s):  
Trevor Wilson ◽  
Usher Posluszny

This study compares the developmental morphology of Parthenocissus quinquefolia Planch. (L.) (Virginia creeper) with that of Parthenocissus tricuspidata (Sieb. & Zucc.) Planch. (Boston ivy) to better understand how the tendril is related to the main shoot architecture of the Vitaceae. Tendril development is looked at from inception to maturity using scanning electron microscopy and epi-illumination microscopy. A tendril primordium is initiated low on the periphery of a shoot apical meristem; this pattern of development is reminiscent of typical monopodial shoot development. A tendril "shoot" in turn produces several bract-opposed branches and resembles the main shoot in its early development. However, a tendril develops through lateral growth, and because it lacks lateral buds, its architecture appears more sympodial than the main shoot. As more tendril branches are produced, the tendril "shoot" pattern of development gradually changes to a pattern of development reported in other vitaceous tendrils. This shift in development suggests how other vitaceous tendrils may be related to the shoot. Because tendril development in Parthenocissus can be demonstrated to be sympodial, it lends evidence to the idea that the unique monopodial-like system in members of the Vitaceae may be derived. The main shoot and tendril development are more similar than has previously been shown.Key words: Vitaceae, Parthenocissus, monopodial, sympodial, tendril, development.

Botany ◽  
2008 ◽  
Vol 86 (1) ◽  
pp. 45-52 ◽  
Author(s):  
Denis Barabé ◽  
Christian Lacroix

The early stages of development of the inflorescence of Anthurium jenmanii Engl. were examined using scanning electron microscopy. The inflorescence of A. jenmanii consists of more than 100 flowers arranged in recognizable spirals. Each flower has four broad tepals enclosing four stamens that are not visible prior to anthesis. The gynoecium consists of two carpels. The floral primordia are first initiated on the lower portion of the inflorescence, they then increase in size and appear as transversely extended bulges. The two lateral tepals are the first organs to be initiated, followed shortly thereafter by the two median tepals. The two lateral stamens are initiated first, directly opposite the lateral tepals, and are followed by two median stamens initiated directly opposite the median tepals. A two-lobed stigma is clearly visible during the early stages of development of the gynoecium. On some of the young inflorescences, all floral parts were covered by extracellular calcium oxalate crystals. The release of these prismatic crystals occurs before the stamens and petals have reached maturity. The mode of floral development observed in Anthurium has similarities with that reported for Gymnostachys . However, contrary to Gymnostachys, the development of the flower of A. jenmanii is not unidirectional.


Rodriguésia ◽  
2019 ◽  
Vol 70 ◽  
Author(s):  
Cleber José da Silva ◽  
João Paulo Oliveira Ribeiro ◽  
Renata Maria Strozi Alves Meira

Abstract Colleters are secretory structures that produce a sticky substance, consisting of a mixture of mucilage, proteins, terpenes, pectic substances and even alkaloids, which lubricates and protects the shoot apical meristem. Several colleter types have been described and have taxonomic value in many botanical families. In Myrtaceae, the colleters description is recent and presents three new morphological types (conic, euryform and petaloid) that differ those already described for other eudicots. In this work, we report the colleters morphological types in six species of three genera belonging to the Myrteae tribe of Myrtoideae from the Brazilian Cerrado. The samples were fixed for light and scanning electron microscopy. Histochemical tests were carried out on the fresh and methacrylate-embedded material. The conic and euryform colleters from Myrtoideae species of the Cerrado did not differ either morphologically nor as to the secretion nature from those described for Myrtoideae species from others biomes, which may indicate their potential use for taxonomic purposes. Considering the hypothesis that the multiple fleshy-fruit lineages have evolved independently in Myrteae tribe, our results indicate the relevance of additional studies in order to recognize the pattern of distribution of colleters in Myrtaceae.


1991 ◽  
Vol 58 (21) ◽  
pp. 2363-2365 ◽  
Author(s):  
Kiyoshi Kanisawa ◽  
Jiro Osaka ◽  
Shigeru Hirono ◽  
Naohisa Inoue

1990 ◽  
Vol 115 (3) ◽  
pp. 482-486 ◽  
Author(s):  
Susan S. Han ◽  
Abraham H. Halevy ◽  
Roy M. Sachs ◽  
Michael S. Reid

Exposure of dormant corms of Triteleia laxa `Queen Fabiola' to 20 ppm C2H4 for 7 days promoted flowering of small corms and resulted in increased apical meristem size, early sprouting, early flowering, more flowers per Inflorescence, and increased fresh weight of daughter corms and cormels. The respiration rate of the C&treated corms increased to four to five times that of the controls during the 7-day treatment, declined markedly after termination of the C2H4 treatment, but remained higher than that of the controls. The C2H4 effects were associated with increased growth rate and consequently a greater final size of the apical meristem (determined by scanning electron microscopy). Leaves produced by C2H4-treated corms were wider, longer, and weighed more than those of the controls.


2004 ◽  
Vol 82 (5) ◽  
pp. 598-606 ◽  
Author(s):  
Christian Lacroix ◽  
Denis Barabé ◽  
Bernard Jeune

The developmental morphology of shoots of Thuja occidentalis L. (eastern white cedar) was investigated using scanning electron microscopy to determine the pattern of initiation of two types of leaves characteristic of higher (third and above) order branches. The shoots of eastern white cedar are bilateral in symmetry and bear leaves in an orthogonal decussate phyllotactic pattern. The shoot system is further characterized by the presence of two alternating and morphologically different pairs of leaves that constitute the basic repeating pattern of the shoot apical meristem (SAM). At maturity the dimorphism between leaf types is marked. Leaves in one plane are wide and flat in comparison with narrower and cup-shaped leaves growing in a plane perpendicular to the other leaf type. The early stages of development of each of the two types of leaves were compared using scanning electron microscopy. During the earliest visible stages of initiation (primordial crest), cup-shaped and flat leaves are very similar in morphology. As individual leaf primordia become more easily delimited as structures by the presence of a furrow between the SAM and the leaf, they differ in terms of width. As they develop further and begin to cover the SAM, the two leaf types are distinguishable morphologically (flat vs. cup shaped). Quantitative parameters such as diameter of the SAM, angle of insertion of individual leaves, and size of leaf primordia (in both a tangential and perpendicular plane) were measured on three categories of leaves: stage 1, earliest visible stage of initiation; stage 2, delineation of leaf primordium from SAM by furrowing; stage 3, leaf primordium partially covering SAM. These measurements corroborate our morphological observations, which show that during early stages of development, flat and cup-shaped leaves are morphologically similar and they diverge in their pattern of development postinitiation, especially as far as leaf width and thickness are concerned. Our results also suggest that the size and shape of the apex goes through a "repeating" cycle and is related to the type of primordium that will be initiated.Key words: Thuja occidentalis, eastern white cedar, leaf development, shoot apical meristem, phyllotaxy, leaf dimorphism.


1998 ◽  
Vol 76 (5) ◽  
pp. 899-904 ◽  
Author(s):  
Gordon D Lemon ◽  
Usher Posluszny

Epi-illumination light microscopy and scanning electron microscopy have been standard techniques for developmental studies of shoot apices. Recently, laser scanning confocal microscopy has gained popularity as a tool for biological imaging. We have adapted laser scanning confocal microscopy to study development in whole shoot apices. It was tested on angiosperm and fern apices using three fluorescent dyes; acriflavine, safranin O, and acid fuchsin, and compared with epi-illumination light microscopy and scanning electron microscopy. In all cases, acid fuchsin proved to be the best fluorochrome for examining shoot apices; having a high affinity for cell walls and nuclear material. The images produced with laser scanning confocal microscopy were sharper and clearer than images generated with epi-illumination light microscopy and scanning electron microscopy. Laser scanning confocal microscopy allows one to map patterns of cell division on the surface of an apical meristem, which is extremely difficult using other techniques such as scanning electron microscopy or epi-illumination light microscopy. Since the laser scanning light microscope records images digitally a method for digital plate production is described. Our methods can easily be applied to study the development of other plant structures on a cellular level such as root apical meristems, floral meristems, stomata, or trichomes, and reproductive organs in lower plants.Key words: confocal microscopy, apical meristem, development, fluorochrome, cytokinesis.


1995 ◽  
Vol 73 (8) ◽  
pp. 1242-1249 ◽  
Author(s):  
Ryoko Imaichi ◽  
Masahiro Kato ◽  
Hiroshi Okada

Scanning electron microscope examinations were performed to characterize the developmental morphology of the outer integument in several species of the three families Annonaceae (Cananga odorata var. fruticosa, Goniothalamus macrophyllus, and Stelechocarpus burahol), Eupomatiaceae (Eupomatia laurina), and Winteraceae (four Tasmannia species). In all species examined, the inner integument arises as an annular ring, but the outer integument initiates as a semiannular outgrowth interrupted on the concave side of the funiculus; the outer integument then becomes hood-shaped. The inner integument overtops the outer one at maturity, and the micropyle consists only of an endostome. Data from the present and previous studies support the hypothesis that the outer integument is hood-shaped in magnolialean angiosperms and that the bilaterally symmetrical, bladelike outer integument is homologous with the ovuliferous sporophyll of the glossopterids. The micropyle consisting of an endostome might be in a primitive state, compared with a bistomic one. Key words: developmental morphology, integument, micropyle, phylogenesis, primitive angiosperms, scanning electron microscopy.


Author(s):  
P.S. Porter ◽  
T. Aoyagi ◽  
R. Matta

Using standard techniques of scanning electron microscopy (SEM), over 1000 human hair defects have been studied. In several of the defects, the pathogenesis of the abnormality has been clarified using these techniques. It is the purpose of this paper to present several distinct morphologic abnormalities of hair and to discuss their pathogenesis as elucidated through techniques of scanning electron microscopy.


Author(s):  
P.J. Dailey

The structure of insect salivary glands has been extensively investigated during the past decade; however, none have attempted scanning electron microscopy (SEM) in ultrastructural examinations of these secretory organs. This study correlates fine structure by means of SEM cryofractography with that of thin-sectioned epoxy embedded material observed by means of transmission electron microscopy (TEM).Salivary glands of Gromphadorhina portentosa were excised and immediately submerged in cold (4°C) paraformaldehyde-glutaraldehyde fixative1 for 2 hr, washed and post-fixed in 1 per cent 0s04 in phosphosphate buffer (4°C for 2 hr). After ethanolic dehydration half of the samples were embedded in Epon 812 for TEM and half cryofractured and subsequently critical point dried for SEM. Dried specimens were mounted on aluminum stubs and coated with approximately 150 Å of gold in a cold sputtering apparatus.Figure 1 shows a cryofractured plane through a salivary acinus revealing topographical relief of secretory vesicles.


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