scholarly journals Palynological Studies of Three Taxa and One F1 Hybrid in the Genus Talinum Adans

2018 ◽  
Vol 10 (2) ◽  
pp. 175-181
Author(s):  
Oluwabunmi Okerinmola AROGUNDADE ◽  
Hameedat O. LAWAL

Acetolysed pollen grains of Talinum paniculatum (Jacq.) Gaertn., Talinum triangulare (Jacq.) Willd. pink petals, Talinum triangulare (Jacq.) Willd. white petals and Talinum triangulare (Jacq.) Willd. pink and white petals F1 hybrid were studied in order to document their morphological structures and ascertain features of taxonomic significance among them. All the taxa have generic features which support their classification as a genus as well as distinct features which ascertain their individuality. Generic features include monad pollen unit, acolpate and monocolpate pollen grains as well as circular and ovate pollen shapes. The delimiting features include additional dyads pollen units in T. triangulare white petal and the F1 hybrid of T. triangulare pink and white petals, quadrangular pollen shape in T. paniculatum, bicolpate pollen grain in the F1 hybrid, tricolpate pollens in   T. triangulare white petal and T. paniculatum, tetracolpate pollens in T. triangulare pink petal and T. paniculatum and pentacolpate pollen grains in T. paniculatum only. The shape of the pores in T. paniculatum also separated it from the varieties and hybrid of T. triangulare. Based on the pollen size, the pollens of T. paniculatum are Media (25 - 50 µm) while those of the two varieties of T. triangulare and their F1 hybrid are Magna (50 - 100 µm). The taxa of Talinum in this study can be separated based on their palynological features.

Phytotaxa ◽  
2019 ◽  
Vol 404 (5) ◽  
pp. 171
Author(s):  
MITRA LAL PATHAK ◽  
MUHAMMAD IDREES ◽  
BO XU ◽  
XIN FEN GAO

Pollen morphology of 27 species of Photinia sensu stricto and five closely related genera of subfamily Maloideae (Rosaceae) were studied in detail. Palynomorphological characteristics were examined using scanning electron microscopy (SEM). Comparative pollen analysis was accomplished based on pollen size, shape, polar and equatorial views, polar and equatorial diameter ratio (P/E ratio), width of aperture, and exine ornamentation. The pollen grains of studied species were found to be monad, tricolporate, small to medium in size (P=17.42–30.45 μm, E=9.26–20.18 μm) and to have shapes oblate-spheroidal (0.88–1.0 μm), prolate-spheroidal (1.01–1.14 μm), sub-prolate (1.15–1.33 μm), prolate (1.34–2 μm), and perprolate (>2 μm). The exine ornamentation was perforated-striate, and two different types were identified. The result of quantitative characters has paltry taxonomic importance. The characters studied here delimit at generic level for some genera but not at species level. The obtained result was partially consistent with that of molecular studies published earlier. The pollen size and shape were found to be different between Asian and American species of Photinia. Especially exine sculpture was found to be an important feature to distinguish species of all genera studied. PCA analysis showed that the pollen shape, pollen sculpture, pollen size, and polarity are the key characters to distinguish the species of Photinia and the closely related genera in subfamily Maloideae. Based on pollen exine, two groups (Type I and Type II) were distinguished. The aim of the present study was to find out the taxonomic significance of palynomorphological characteristics in subfamily Maloideae (Rosaceae).


2018 ◽  
Vol 10 (2) ◽  
pp. 205-210 ◽  
Author(s):  
Sekinat Okikiola AZEEZ ◽  
Julius Olaoye FALUYI

Interspecific reciprocal crosses among four Nigerian Physalis species (Physalis angulata, P. micrantha, P. pubescens and P. peruviana) were carried out by transferring desired pollen grains to ovalate parents, bagged and labelled to prevent contamination by external pollen grains and for easy identification. Pollen cells of the F1 hybrid combination from the only viable cross (P. angulata x P. pubescens) were studied using standard cytogenetic techniques. The F1 hybrid obtained in the current investigation produced few flower buds and no matured fruit was harvested. Its average pollen grain diameter was found within the range of that of the two genitors and the pollen stainability was less than 50%. The hybrid was also characterized by meiotic irregularities. Based on the results obtained, the study concluded that P. pubescens is closely related to P. angulata and P. peruviana, while P. micrantha is more distant from them since the formal individuals were able to cross reciprocally among each other, though no matured fruit was produced except in one cross (P. angulata x P. pubescens).


2020 ◽  
Vol 8 (4) ◽  
pp. 131-138
Author(s):  
Rizgar Y. Ismail ◽  
Saleem E. Shahbaz

The polleniferous material of Centaurea taxa grow in Kurdistan-Iraq was collected. Samples were tested using scanning electron microscopy (SEM) and light microscopy (LM). In the polar view, pollen grain outlines are mostly triangular or triangular-circular. In equatorial view, the elliptic shape is common, while circulars or semicircular shapes are rare. The exine sculpture is scabrate, and the tectum is perforate. Number of sculpture microspinules/ µm², and their heights together with the number of wall perforations provide significant characters for taxa delimitation. Pollen grains of all species are of medium size, very few of some species pollen are larger or smaller in size. Species producing subprolate pollen shape is common, while oblate spheroidal and Prolate spheroidal shapes are less common. The principal component analysis and the discriminant analysis can recognize 65.478% and 87.54% of the total variability respectively; moreover, the discriminant function can correctly classify 125 or 78.125% out of 160 observations for pollen traits. 


2020 ◽  
Author(s):  
Hui Feng ◽  
Naizhe Ji ◽  
Yu Xie ◽  
Beibei Ge ◽  
Yanhua Bu ◽  
...  

Abstract Background Although triploid plants are often assumed to be sterile, in Rosa, triploids appear to have been important in both species evolution and breeding. A better understanding of the fertility of China Rosa triploids and their behavior when used in interploidy crosses will not only improve gene introgression from China triploid roses to modern roses, but also enhance our understanding of male and female fertility mechanism with triploids. The objective of this study was to evaluate the usefulness of five triploid China roses for breeding by measuring the pollen size, quantifying the fertility and following the ploidy transmission of interploidy crosses. Results In the five triploids, the pollen grain size of Rosa multiflora var. cathayensis Rehd ‘Fen Tuan Qiang Wei’ followed a normal distribution, suggesting that 1 mainly ploidy level pollen grain were produced, while the pollen size of other 4 triploids followed skewed, flattened, and slightly bimodal distributions, indicating a wide range of chromosome numbers. Although none of the 5 triploids produced hips as females, 3 gave good hip and seed production on the tetraploid mother plant when used as the pollen parents. Based on the ploidy level analysis of their progeny, ‘Fen Tuan Qiang Wei’ produced 1n viable pollen whereas ‘Chun Shui Lü Bo’ and ‘Yu Shi Zhuang’ produced 2n viable pollen. In the meiosis of triploids, the triads, pentads and microcyte in the meiosis products indicated the objective triploid production of euploid pollen grains. Conclusions In this study we reported 1 China triploid rose produces 1n viable pollen, and 2 China triploid roses produce 2n viable pollen, and no anueploid progeny was produced. Our results indicate that the triploids contribute significantly to tetraploids formation in the crossing system of Genus Rosa, and it is possible for breeders to create novel rose types with valuable triploids in the future. With the special triploid resources found in this experiment, Genus Rosa will be an excellent material to study the mechanism of triploids in the future.


1938 ◽  
Vol 16c (11) ◽  
pp. 445-455 ◽  
Author(s):  
F. H. Peto

Complete analyses of pollen-mother-cell nuclei at first metaphase, percentage good pollen, pollen diameter and pollen-size distribution were determired for the following poplar species and natural hybrids: Populus grandidentata Michx., P. tremuloides Michx., P. eugenei Simon Louis, P. alba L., P. canescens Sm., natural hybrids of P. alba × P. grandidentata and of P. alba × P. tremuloides.Both of the P. alba and two of the four P. canescens trees examined were triploids (2n = 57) while all other trees examined were diploids (2n = 38). Meiotic observations on the natural hybrids indicated a high degree of homology between the chromosomes of P. alba and the native aspens (P. grandidentata and P. tremuloides), since 17 to 19 bivalents were usually found at first metaphase. In collections from one triploid P. canescens and two diploid alba-grandidentata hybrid trees, failure of a high proportion of the chromosomes to pair was attributed to genetic factors limiting pairing, rather than to non-homology.Pollen characters such as percentage good pollen, pollen diameter, and pollen size distribution were, in most cases, not indicative of the chromosome number or pairing relations at first metaphase. Consequently, triploids could not be detected by pollen observations under the conditions of this experiment. In spite of the lack of correlation between first metaphase and pollen observations, abnormally large pollen grains were observed in collections from several of the trees, and these were considered to contain the diploid or unreduced chromosome complement. The tendency for the poplars to produce unreduced pollen grains probably accounts for the number of triploid trees discovered in Canada and Sweden.


Forests ◽  
2018 ◽  
Vol 9 (8) ◽  
pp. 444
Author(s):  
Fumio Nakazawa ◽  
Yoshihisa Suyama ◽  
Satoshi Imura ◽  
Hideaki Motoyama

Pollen taxa in sediment samples can be identified based on morphology. However, closely related species do not differ substantially in pollen morphology, and accurate identification is generally limited to genera or families. Because many pollen grains in glaciers contain protoplasm, genetic information obtained from pollen grains should enable the identification of plant taxa at the species level. In the present study, species identification of Pinus pollen grains was attempted using whole-genome amplification (WGA). We used pollen grains extracted from surface snow (depth, 1.8–1.9 m) from the Belukha glacier in the summer of 2003. WGA was performed using a single pollen grain. Some regions of the chloroplast genome were amplified by PCR, and the DNA products were sequenced to identify the pollen grain. Pinus includes approximately 111 recognized species in two subgenera, four sections, and 11 subsections. The tree species Pinus sibirica and P. sylvestris are currently found at the periphery of the glacier. We identified the pollen grains from the Belukha glacier to the level of section or subsection to which P. sibirica and P. sylvestris belong. Moreover, we specifically identified two pollen grains as P. sibirica or P. cembra. Fifteen species, including P. sibirica, were candidates for the remaining pollen grain.


2017 ◽  
Vol 24 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Ebadi-Nahari Mostafa ◽  
Nikzat-Siahkolaee Sedigheh ◽  
Eftekharian Rosa

Pollen morphology of nine species representing four genera: Cephalaria Schrad, Dipsacus L., Pterocephalus Vaill. and Scabiosa L. of the family Dipsacaceae in Iran has been investigated by means of scanning electron microscopy (SEM). The results showed that pollen grains were triporate and tricolpate. The pollen type of Scabiosa rotata Bieb. (tri- and tetraporate) is the first report in the world. The sizes of pollen grains fall into the classification group magna (pollen grain diameter 50–100 μm). Pollen shapes vary from preoblate to prolate and their polar views were triangulate and lobate. The exine ornamentation varies from gemmate in S. rotata to spinulate in the rest studied species. Species of Scabiosa have been dispersed in UPGMA tree that this confirmed the previous studies about taxonomic problems and species complexity in this genus. These results show the transfer of the some Scabisoa species to Lomelosia Raf. based on palynological characters. Pollen morphology of the family is helpful at the generic and specific level.Bangladesh J. Plant Taxon. 24(2): 129–136, 2017 (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)


2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Gotelli ◽  
B. Galati ◽  
D. Medan

Tapetum, orbicule, and pollen grain ontogeny inColletia paradoxaandDiscaria americanawere studied with transmission electron microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells and related to orbicule and pollen grain formation are described. The proorbicules have the appearance of lipid globule, and their formation is related to the endoplasmic reticulum of rough type (ERr). This is the first report on the presence of orbicules in the family Rhamnaceae. Pollen grains are shed at the bicellular stage.


2007 ◽  
Vol 97 (8) ◽  
pp. 892-899 ◽  
Author(s):  
Khalid Amari ◽  
Lorenzo Burgos ◽  
Vicente Pallas ◽  
María Amelia Sanchez-Pina

The route of infection and the pattern of distribution of Prunus necrotic ringspot virus (PNRSV) in apricot pollen were studied. PNRSV was detected both within and on the surface of infected pollen grains. The virus invaded pollen during its early developmental stages, being detected in pollen mother cells. It was distributed uniformly within the cytoplasm of uni- and bicellular pollen grains and infected the generative cell. In mature pollen grains, characterized by their triangular shape, the virus was located mainly at the apertures, suggesting that PNRSV distribution follows the same pattern as the cellular components required for pollen tube germination and cell wall tube synthesis. PNRSV also was localized inside pollen tubes, especially in the growth zone. In vitro experiments demonstrated that infection with PNRSV decreases the germination percentage of pollen grains by more than half and delays the growth of pollen tubes by ≈24 h. However, although PNRSV infection affected apricot pollen grain performance during germination, the presence of the virus did not completely prevent fertilization, because the infected apricot pollen tubes, once germinated, were able to reach the apricot embryo sacs, which, in the climatic conditions of southeastern Spain, mature later than in other climates. Thus, infected pollen still could play an important role in the vertical transmission of PNRSV in apricot.


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