scholarly journals Systematic implications of achene characteristics in genera Centaurea L., Cyanus Mill., Psephellus Cass. and Rhaponticoides Vaill. (Asteraceae)

2015 ◽  
Vol 22 (2) ◽  
pp. 125-136 ◽  
Author(s):  
Mehmet Bona

This study examines the exomorphic achene characteristics of 23 taxa belonging to Centaurea, Cyanus, Psephellus and Rhaponticoides in Asteraceae using light microscope and scanning electron microscope (SEM). The exomorphic characteristics studied are shape, size, colour and surface pattern of achene, and hair, length and colour of pappus. The results of the present investigation showed that achene size of the studied taxa is 3–7 × 1–4 mm. Pappus length is 1–14 mm, deciduous for three taxa and inner row is differentiated from the outer, 1–3 mm long, for 10 taxa. SEM studies showed eight different types of achene surface patterns for the studied taxa: Glebulate, glebulate-ruminate, reticulate, ribbed, ruminate, smooth, smooth-glebulate and undulate. Achene characteristics are useful for both intrageneric and intraspecific classification of the studied taxa.Bangladesh J. Plant Taxon. 22(2): 125-136, 2015 (December)

2015 ◽  
Vol 22 (2) ◽  
pp. 99-110 ◽  
Author(s):  
Maryam Naderifar ◽  
Ali Sonboli ◽  
Abbas Gholipour

Pollen morphology of 11 Iranian Dracocephalum L. species was investigated using light and scanning electron microscopy to evaluate their taxonomic significance for the infrageneric classification of the genus. Pollen grains of all examined taxa were isopolar, hexacolpate, circular in polar view and spheroidal to prolate in equatorial view (P/E = 1.0?2.0). The smallest pollen grains were observed in D. aucheri (P = 29.7 ?m, E = 22.6 ?m), while the largest pollen was found in D. lindbergii (P = 45.1 ?m, E = 33.7 ?m). The highest and lowest apocolpium index (AI) were measured in D. aucheri (AI = 0.27) and D. surmandinum (AI = 0.08), respectively. Colpus membrane was egranulate in all examined species except for D. multicaule and D. ghahremanii. The main exine ornamentation type was characterized as bireticulate including five different subtypes. The results revealed that the exine ornamentation is a diagnostic character useful for the classification of Dracocephalum.Bangladesh J. Plant Taxon. 22(2): 99-110, 2015 (December)


2011 ◽  
Vol 361-363 ◽  
pp. 288-295
Author(s):  
De Wei Chen ◽  
Xiao Ling Ge ◽  
Quen Tin Shi ◽  
Jiu Wang Tian

Using scanning electron microscope, the microscopic pictures of the surface on sediment have been obtained from the sub-micron titanium dioxide suspensions without dispersant or adding different types of dispersants. Deposits of titanium dioxide suspension have been observed and the mechanism of the dispersant has been analyzed. Meanwhile, deposits of titanium dioxide gray distribution figure have been gained by self-compiled Matlab program, which proved that the surface sediments is fractal, and the fractal dimension has been calculated under different conditions. The rules between suspension stability and fractal dimension have been achieved.


1980 ◽  
Vol 28 (1) ◽  
pp. 123 ◽  
Author(s):  
RC Carolin

The surface patterns of seeds of 88 species of Goodenia and related genera were examined under scanning electron microscope and light microscope. With use of sections as well, the patterns were resolved into six attributes of which each was present in one of at least two states. Certain combinations of states of attributes are used to define terms which are used for purposes of taxonomic description. Six such terms are defined in this way. The results indicate that previous taxonomic arrangements are unsatisfactory. A brief commentary on possible evolutionary trends is provided and the relationships of the various satellite genera to Goodenia are discussed.


2013 ◽  
Vol 20 (1) ◽  
pp. 61-65
Author(s):  
M. Ajmal Ali ◽  
Fahad M.A. Al-Hemaid ◽  
Arun K. Pandey ◽  
Joongku Lee

Studies on spermoderm using scanning electron microscope (SEM) were undertaken in 12 taxa under 11 genera of the family Cucurbitaceae sampled from India, China and Korea. The spermoderm pattern in the studied taxa varies from rugulate, reticulate to colliculate type. The spermoderm shows rugulate type in Benincasa hispida and Sicyos angulatus; reticulate type in Citrullus colocynthis, Cucumis melo var. agrestis, Diplocyclos palmatus, Hemsleya longivillosa, Luffa echinata, Momordica charantia, M. cymbalaria, Schizopepon bryoniifolius, and Trichosanthes cucumerina; and colliculate type  in Gynostemma laxiflorum. The present study clearly reveals that the testa features greatly varies across the genera which can be used as micromorphological markers for identification as well as character states for deducing relationship of the taxa within the family.DOI: http://dx.doi.org/10.3329/bjpt.v20i1.15465Bangladesh J. Plant Taxon. 20(1): 61-65, 2013 (June)


2010 ◽  
Vol 92 ◽  
pp. 283-288 ◽  
Author(s):  
Ming Shan Yang

The wollastonite/PP composites were manufactured by twin-screw extruder and the effects of compatabilizer, feeding method and screw configuration on the properties of wollastonite/PP composites were investigated in this paper. The dispersion of fibrous wollastonite in PP matrix was determined by scanning electron microscope (SEM). The results showed that the strength, toughness and flowability of the composite were simultaneously guaranteed by using three different types of PP resins, and the interfacial adhesion was improved greatly by adding the compatabilizer of PP-g-MAH, which increases the comprehensive properties of wollastonite/PP composite. The fibrous dispersion of wollastonite in PP matrix was achieved by using of side feeding and the weak-shear screw configuration, which reaches the good reinforcing effect.


2011 ◽  
Vol 74 (2) ◽  
pp. 159-166 ◽  
Author(s):  
Tomislav Bačić ◽  
Ljiljana Krstin ◽  
Jadranka Roša ◽  
Željko Popović

Condition of epistomatal wax on the abaxial surface of the current and previous-year needles of damaged silver fir trees (<em>Abies alba</em> Mill.), both from the polluted Risnjak and "clean" Donja Dobra sites in Gorski Kotar region, both influenced by pollutants coming from Europe, during two years, three times a year, were examined with Scanning Electron Microscope. In the course of time the wax tubules on the epistomatal rims of stomata in polluted, but also in "clean" needles surface, become fused and agglomerated rapidly to various extents of morphologically different types of amorphous wax crusts, primarily compact and particulate ones. This process begins very early, especially in polluted Risnjak site, and may be interpreted as a possible result of air pollution. However, the recrystalization, or production of new tubules, also appears relatively quickly in mostly cases. Quantitative estimations indicate a very large total amount of amorphous wax crusts in the current-year needles, and a very high percentage of the same wax in previous-year needles. Amorphous wax crusts cover stomatal pores, as well as the rims, disturbing the normal gas exchange. Statistically there is a signicant tendency of increase in wax degradation in the needles of the polluted site in comparison with those of the unpolluted one, but there is an insignificant wax degradation among the needles of damaged trees within each site. These results confirmed most of the research done in our preliminary report.


2014 ◽  
Vol 21 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Tulay Aytas Akcin ◽  
Adnan Akcin

Micromorphological characters of achenes in seven taxa of Turkish Achillea L. (Asteraceae) were investigated using stereomicroscope and scanning electron microscope (SEM). Some morphological descriptions of achenes were given for each species. A.biserrata Bieb. has the biggest (0.69±0.092 x 2.01±0.252 mm) and A. grandiflora Friv. has the smallest (0.30±0.018 x 1.12±0.058 mm) achenes. The achenes are oblong-lanceolate in A.biserrata and A. teretifolia Willd. and they are oblong in the remaining taxa. In surface sculpturing, the ornamentation and slime cell distribution varied among the taxa. However, A. biebersteinii Afan. has distinct slime cells forming groups scattered over the achene surface. Mature achenes are ribbed and glabrous in all studied taxa. A. biserrata has distinct carpopodium structure.DOI: http://dx.doi.org/10.3329/bjpt.v21i1.19253Bangladesh J. Plant Taxon. 21(1): 19-25, 2014 (June)


Author(s):  
P. P. C. Graziadei

Ciliary structures are closely associated to two main functions: movement and sensory perception. In olfactory receptors they are postulated as essential specific devices in the mechanism of olfactory transduction. If the postulate is correct, all olfactory receptors should be provided with cilia. The comparative anatomy provides a suitable test for this hypothesis. It is well known that vomero-nasal receptors respond to odors with modalities similar to the olfactory receptors proper. In several species of turtles the vomeronasal epithelium is fully exposed in the nasal cavity so that a surface study with the scanning electron microscope can demonstrate in one single preparation the texture and surface pattern of respiratory, olfactory and vomero-nasal areas.


1981 ◽  
Vol 59 (5) ◽  
pp. 683-688 ◽  
Author(s):  
R. W. Rose Jr. ◽  
C. Gerald Van Dyke ◽  
C. B. Davey

Three different types of ectomycorrhizae found in the Southeastern United States on Eucalyptus nova-anglica and identified as being formed by Cenococcum geophilum, Pisolithus tinctorius, and Scleroderma geaster were examined with a scanning electron microscope (SEM). In overall appearance the three types of mycorrhizae could be distinguished easily from each other, particularly C. geophilum, which had a relatively smooth, undulate surface in comparison with the other two types. Detailed descriptions and comparisons of these ectomycorrhizae are given and the value of SEM in characterizing ectomycorrhizae is discussed


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