scholarly journals Enhancement of Growth and Flowering of Triteleia laxa by Ethylene

1990 ◽  
Vol 115 (3) ◽  
pp. 482-486 ◽  
Author(s):  
Susan S. Han ◽  
Abraham H. Halevy ◽  
Roy M. Sachs ◽  
Michael S. Reid
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Growth Rate ◽  
Respiration Rate ◽  
Apical Meristem ◽  
Day Treatment ◽  
Fresh Weight ◽  
Final Size ◽  
Meristem Size ◽  
Scanning Electron

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.

scholarly journals New registers of colleters in species of Myrtaceae from Brazilian Cerrado

Rodriguésia ◽  
2019 ◽  
Vol 70 ◽  
Author(s):  
Cleber José da Silva ◽  
João Paulo Oliveira Ribeiro ◽  
Renata Maria Strozi Alves Meira
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Shoot Apical Meristem ◽  
Apical Meristem ◽  
Fleshy Fruit ◽  
Brazilian Cerrado ◽  
Secretory Structures ◽  
Histochemical Tests ◽  
Potential Use ◽  
Scanning Electron

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.

scholarly journals Microstructure Evolution and Coarsening of θ′-Al2Cu Precipitates in a Creep Aged Al-Cu-Mn Alloy

2021 ◽  
Vol 2101 (1) ◽  
pp. 012071
Author(s):  
Soban Muddassir Dar ◽  
Yutao Zhao ◽  
Hengcheng Liao ◽  
Xizhou Kai
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Growth Rate ◽  
Microstructure Evolution ◽  
Average Length ◽  
Transmission Electron ◽  
Creep Exposure ◽  
Creep Temperature ◽  
Scanning Electron

Abstract This paper describes the microstructure evolution in a creep aged Al-Cu-Mn alloy using optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Results show the sub-grains formation and accelerated coarsening of θ′ precipitates in creep aged samples. It is observed that at an applied stress of 50MPa, as the creep temperature increases the average length of θ′ precipitates increases and their aspect ratio first increases then decreases. It is also found that after 100h of creep exposure at 200°C/50MPa, θ′ precipitates have grown to an average length of 279nm; at 225°C/50MPa to an average length of 425nm and at 250°C/50MPa they have grown to an average length of 844nm. Coarsening/growth rate of the precipitates is described by Lifshitz-Slyozov-Wagner (LSW) model.

Early stages of initiation of two types of leaves in Thuja occidentalis (eastern white cedar)

2004 ◽  
Vol 82 (5) ◽  
pp. 598-606 ◽  
Author(s):  
Christian Lacroix ◽  
Denis Barabé ◽  
Bernard Jeune
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Apical Meristem ◽  
Leaf Primordia ◽  
Leaf Primordium ◽  
Thuja Occidentalis ◽  
White Cedar ◽  
Early Stages ◽  
Eastern White Cedar ◽  
Scanning Electron

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.

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
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Apical Meristem ◽  
Lateral Growth ◽  
Developmental Morphology ◽  
Main Shoot ◽  
Lateral Buds ◽  
Shoot Architecture ◽  
Parthenocissus Quinquefolia ◽  
Scanning Electron

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.

A critical assessment of criteria used in the taxonomy of the genus Rhizopus

1983 ◽  
Vol 61 (9) ◽  
pp. 2374-2383 ◽  
Author(s):  
R. J. Seviour ◽  
D. E. Pitt ◽  
S. McClure ◽  
J. Pyle
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Growth Rate ◽  
Radial Growth ◽  
Critical Assessment ◽  
Radial Growth Rate ◽  
Diagnostic Usefulness ◽  
Taxonomic Studies ◽  
Scanning Electron ◽  
Interspecific Diversity

Scanning electron microscopy (SEM) and cultural physiology data have been used to assess their taxonomic applicability in delimiting species of the genus Rhizopus. SEM of the sporangiospores of a variety of isolates indicates that there is a continuum of patterns ranging from almost featureless surfaces to verruculose and deeply ridged or striated topologies. The degree of interspecific diversity was sufficient to reduce the diagnostic usefulness of this feature for interspecies delineation. Cultural characteristics, radial growth rate, sporulation pattern, and growth and viability at raised temperatures were also too variable for use in taxonomic studies.

Ochroconis ferulica sp. nov. (Venturiales), a fungal endophyte from Ferula ovina

Nova Hedwigia ◽  
2020 ◽  
Vol 110 (3) ◽  
pp. 369-381 ◽  
Author(s):  
Zahra Tazik ◽  
Kamran Rahnama ◽  
Mehrdad Iranshahi ◽  
James Francis White ◽  
Hassan Soltanloo
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Growth Rate ◽  
Ribosomal Rna ◽  
Slow Growth ◽  
Colony Growth ◽  
Fungal Endophyte ◽  
Molecular Evidence ◽  
Similar Species ◽  
Scanning Electron

A fungus with dark brown hyphae, thick melanized walls and slow growth was isolated from roots of Ferula ovina without any symptoms of disease. In a Bayesian inference phylogenetic analysis, the fungus clustered in a clade containing species with mostly 4-celled conidia as a sister of Ochroconis longiphorum, differing from that species in source of isolation, colony growth rate, conidial size and shape. Morphological and molecular evidence using Field Emission Scanning Electron Microscopy (FESEM) and nuclear ribosomal RNA regions (ITS and nucLSU) separated this isolate from other known Ochroconis species. Based on this strain, Ochroconis ferulica sp. nov. is firstly described, illustrated, and compared with similar species.

A new approach to the study of apical meristem development using laser scanning confocal microscopy

1998 ◽  
Vol 76 (5) ◽  
pp. 899-904 ◽  
Author(s):  
Gordon D Lemon ◽  
Usher Posluszny
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Confocal Microscopy ◽  
Light Microscopy ◽  
Laser Scanning ◽  
Apical Meristem ◽  
Laser Scanning Confocal Microscopy ◽  
Shoot Apices ◽  
Scanning Confocal Microscopy ◽  
Scanning Electron

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.

A Comparative Study of the Morphology of 3C-SiC Grown at Different C/Si Ratios

2009 ◽  
Vol 615-617 ◽  
pp. 153-156 ◽  
Author(s):  
Giovanni Attolini ◽  
Bernard Enrico Watts ◽  
Matteo Bosi ◽  
Francesca Rossi ◽  
Ferenc Riesz
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Growth Rate ◽  
Comparative Study ◽  
Surface Defects ◽  
Force Microscopy ◽  
Atomic Force ◽  
Silane Precursor ◽  
Sic Films ◽  
Scanning Electron

A comparative study of the morphology of 3C-SiC films prepared with different C:Si ratios is presented. The silane precursor controls the growth rate at all values of C:Si ratio but combined of observations using Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) indicates that the C:Si ratio is critical in determining the grain size and at values of C:Si close to 1 texturing and faceting become evident. Makyoh Topography reveals various surface defects, a slight mesoscale roughness and bending of the epiwafers.

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