2n GAMETES IN DIPLOID SOLANUM: FREQUENCY AND TYPES OF SPINDLE ABNORMALITIES

1982 ◽  
Vol 24 (3) ◽  
pp. 301-314 ◽  
Author(s):  
R. E. Veilleux ◽  
N. A. McHale ◽  
F. I. Lauer
Keyword(s):  
Cross Sections ◽  
Meiotic Division ◽  
2N Gametes ◽  
Anatomical Study ◽  
Solanum Phureja ◽  
Spindle Orientation ◽  
Pollen Production ◽  
2N Pollen ◽  
Genetic Theory ◽  
Parallel Spindles

Cytological disturbances resulting in 2n pollen were examined in four clones of diploid (2x = 24) Solanum phureja Juz. and Buk.; two (148-17 and 127-14) were variable and two (154-1 and B2-11) were consistently high in 2n pollen production. Three types of abnormal spindle orientation were observed at the second meiotic division: fused, tripolar, and parallel spindles (fs, tps, and ps, respectively). All four genotypes had fs. Three had tps, and ps was least frequent, occuring in two genotypes only. Cross-sections of buds revealed that all three abnormalities can occur in adjacent cells of a locule. In all genotypes, fs predominated at high levels of expression of 2n gametes. At lower levels of expression (i.e. less than 60%, which occurred only in 148-17 and 127-14), however, the frequencies of tps and ps increased. In general, there was little evidence for localization of dyads (resulting from fs or ps) or tetrads (resulting from normal divisions) within cross sections of locules, but 52.4% of all tetrads which occurred in a single locule of genotype 127-14 were found in 25% of the locular area. Cross-sections of buds revealed variation in frequency of 2n gametes among anthers (61.7 vs. 5.6% in 148-17) and between locules of an anther (73.1 vs. 90.0% in B2-11). Implications of the anatomical study were applied to current genetic theory regarding the development of 2n gametes in potato species.

THREE MECHANISMS OF 2n POLLEN FORMATION IN DIPLOID POTATOES

1975 ◽  
Vol 17 (2) ◽  
pp. 217-225 ◽  
Author(s):  
D. W. S. Mok ◽  
S. J. Peloquin
Keyword(s):  
Meiotic Division ◽  
Genetic Data ◽  
The Other ◽  
Cleavage Furrow ◽  
2N Pollen ◽  
Parallel Spindles ◽  
Solatium Tuberosum ◽  
Pollen Formation ◽  
Group Tuberosum

Three mechanisms of 2n pollen formation observed in diploid hybrids between Solatium tuberosum Group Phureja (2x) and haploids of S. tuberosum Group Tuberosum (4x) are termed parallel spindles (ps), premature cytokinesis 1 (pc 1) and premature cytokinesis 2 (pc 2). A II spindles are parallel to each other in many cells of clones producing 2n pollen by ps. A single cleavage furrow follows and forms a dyad which generates two 2n microspores. The other two mechanisms, pc 1 and pc 2, produce 2n pollen by omission of the second meiotic division. Premature cytokinesis 1 (pc 1) involves asynchronized movement of bivalents to and from the M I plate and falling apart of chromatids at T I. A cleavage furrow follows the first meiotic division, no second division occurs and products of meiosis are dyads. Premature cytokinesis 2 (pc 2) exhibits no abnormalities at the first meiotic division. However, cytokinesis occurs prematurely at P II, no second division occurs, and only dyads are formed. Genetic data suggested that these three mechanisms may be controlled by single loci, and are inherited independently as simple recessives.

Use of Ipomoea trifida (HBK.) G. Don germ plasm for sweet-potato improvement. 2. Fertility of synthetic hexaploids and triploids with 2n gametes of I. trifida, and their interspecific crossability with sweet potato

Genome ◽  
1991 ◽  
Vol 34 (2) ◽  
pp. 209-214 ◽  
Author(s):  
Rosanna Freyre ◽  
Masaru Iwanaga ◽  
Gisella Orjeda
Keyword(s):  
Sweet Potato ◽  
Egg Production ◽  
Ipomoea Batatas ◽  
2N Gametes ◽  
Pollen Production ◽  
2N Pollen ◽  
Ipomoea Trifida ◽  
Potato Improvement ◽  
Synthetic Hexaploids ◽  
Interspecific Crossability

Twenty-two synthetic hexaploids and 33 triploids with 2n pollen production of Ipomoea trifida were used in crosses to estimate their male and female fertility and their crossability with sweet potato, Ipomoea batatas (L.) Lam. Several important conclusions were drawn. (i) The fertility of pollen of the triploid plants was confirmed, which suggested they are truly functional 2n pollen. (ii) The average male fertility of hexaploid plants was higher than that of triploid with 2n pollen production plants. (iii) 2n egg production was observed in several triploid genotypes, (iv) From a polycross, 3079 seeds with normal shapes were produced. These represent a population of hexaploid I. trifida with a wide genetic base, and they may be important material for sweet-potato improvement, (v) A total of 3275 seeds were obtained from crosses with six sweet-potato female parents, of which only 60 germinated, indicating the existence of an interspecific barrier. The implications of 2n gametes for breeding and evolution of sweet potato are also discussed.Key words: Ipomoea batatas, Ipomoea trifida, 2n gametes, sexual polyploidization, triploid.

scholarly journals Distribution of Microtubular Cytoskeletons and Organelle Nucleoids During Microsporogenesis in a 2n Pollen Producer of Hybrid Populus

2009 ◽  
Vol 58 (1-6) ◽  
pp. 220-226 ◽  
Author(s):  
J. Wang ◽  
X. Y. Kang
Keyword(s):  
Indirect Immunofluorescence ◽  
Pollen Grains ◽  
Pollen Production ◽  
2N Pollen ◽  
Meiotic Abnormalities ◽  
Chromosome Behavior ◽  
Dapi Staining ◽  
Populus Simonii ◽  
Parallel Spindles ◽  
The Relationship

Abstract The distribution of microtubular cytoskeletons and organelle nucleoids during microsporogenesis in Populus simonii Carr. x P. nigra L. ‘Tongliao’ was studied by indirect immunofluorescence and 4’,6-diamidino-2- phenylindole (DAPI) staining. Our purpose was to reveal the relationship between changes in microtubule and chromosome behavior and cytokinesis and to explain the mechanism of 2n pollen production. We observed stable frequencies of 2n pollen production, ranging from 1.56% to 2.29%, between 2006 and 2008. Moreover, conjoined pollen grains were also observed. Meiotic abnormalities, including univalents, lagging chromosomes and micronuclei, were observed during microsporogenesis. Triads and dyads were also detected in meiotic products. Parallel spindles in metaphase II were unable to fuse, owing to the existence of an organelle band. Regularly, in telophase II, primary phragmoplasts were organized between sister nuclei, and secondary phragmoplasts formed between non-sister nuclei. Cell plates were initiated by centrifugal expansion of phragmoplasts and cytoplasmic infurrowing started at the junctions between the microsporocyte wall and the expanded phragmoplasts. However, a secondary phragmoplast was absent in some microsporocytes. These observations suggest that the occurrence of 2n pollen may result from the partial failure of cytokinesis caused by the absence of secondary phragmoplasts in this hybrid.

scholarly journals Morphological and phytochemical analysis of leaves and stems of Tetrapterys multiglandulosa CAV.

2020 ◽  
pp. 959-964
Author(s):  
Gilberto Gonçalves Facco ◽  
Eloty Justina Schleder ◽  
Natalia Yoshioka de Vidis ◽  
Maristela Halverson ◽  
Rosemary Matias ◽  
...  
Keyword(s):  
Cross Sections ◽  
Clinical Signs ◽  
Single Layer ◽  
Anatomical Study ◽  
Phytochemical Analysis ◽  
Native Plant ◽  
Circular Section ◽  
Vegetative Organs ◽  
Ethanol Extracts ◽  
Columnar Cells

This study aimed to carry out morphoanatomical, histochemical and phytochemical analysis of leaves and stems of Tetrapterys multiglandulosa Cav. (Malpighiaceae), a native plant responsible for abortion and sudden death in beef cattle. Plant specimens underwent anatomical study, in which leaves and stems were dried and ground with aqueous and ethanol extracts subjected to histochemical and phytochemical analysis. Anatomical observation of vegetative organs detected the presence of simple columnar cells in the adaxial epidermis, palisade mesophyll, parenchyma with a layer of cells and paracitic type stomata. Stem cross-sections presented circular section, single layer (uniseriate) epidermis with thick cuticle and Malpighi’s trichomes, the phelogen was in differentiation. The cortex showed angular collenchyma, parenchyma with exogenous channels and druse shaped calcium oxalate crystals. Phytochemical tests of aqueous and ethanol extracts of leaves and stems indicated the presence of phenolic compounds, tannins, flavonoids, saponins, alkaloids and cardiotonic heterosides. Potentially phytotoxic secondary metabolites evidenced in the leaves and stems, including saponins and cardiotonic heterosides were correlated with clinical signs observed in intoxicated animals.

Genomic composition of 4x–2x potato hybrids: influence of Solanum chacoense

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 413-420 ◽  
Author(s):  
Fouzia Bani-Aameur ◽  
F. I. Lauer ◽  
R. E. Veilleux ◽  
A. Hilali
Keyword(s):  
Solanum Tuberosum ◽  
Interspecific Hybrids ◽  
Tuber Yield ◽  
Solanum Chacoense ◽  
Solanum Phureja ◽  
2N Pollen ◽  
Fall Season ◽  
Tuber Set ◽  
Target Environment ◽  
Breeding Selections

Tetraploid potato hybrids representing three genomic compositions (TTTT, TTPP, and TTPC (T, Solanum tuberosum; P, Solanum phureja; C, Solanum chacoense)) were constructed by crossing S. tuberosum (2n = 4x = 48) cultivars or advanced breeding selections among themselves or with 2n pollen producing selections of either S. phureja (2n = 2x = 24) or F1 hybrids between S. phureja and S. chacoense (2n = 2x = 24). Seedling families were evaluated in the fall season and selections within each family were evaluated in spring trials at Ait-Melloul, Morocco. Genomic composition was the greatest source of variance for yield-attributing traits, with TTPC outperforming other hybrids in fall trials for vine vigor, tuber set, and tuber yield and TTPP outperforming other hybrids in spring trials for the same traits. The results imply that analytic breeding for potato by construction of complex interspecific hybrids may result in clones surpassing a previously proposed heterotic threshold if the target environment is conducive to expression of favorable traits from alien germ plasm.Key words: Solanum phureja, Solanum chacoense, Solanum tuberosum, 4x–2x hybrids, potato, analytic breeding.

2n pollen formation via parallel spindles in the potato cultivar sebago

1980 ◽  
Vol 57 (9) ◽  
pp. 449-455 ◽  
Author(s):  
E. W. Souter ◽  
J. C. Dawe ◽  
S. J. Peloquin
Keyword(s):  
Potato Cultivar ◽  
2N Pollen ◽  
Parallel Spindles ◽  
Pollen Formation

An anatomical study of the myelination of human laryngeal nerves

2011 ◽  
Vol 125 (12) ◽  
pp. 1263-1267 ◽  
Author(s):  
J C Fleming ◽  
N Gibbins ◽  
P J Ingram ◽  
M Harries
Keyword(s):  
Recurrent Laryngeal Nerve ◽  
Cross Sections ◽  
Recovery Of Function ◽  
Superior Laryngeal Nerve ◽  
Anatomical Study ◽  
Laryngeal Nerve ◽  
Clinical Consequence ◽  
Laryngeal Nerves ◽  
Significant Difference ◽  
Myelinated Fibres

AbstractObjective:To determine the differences in myelination between the human recurrent laryngeal nerve and superior laryngeal nerve.Methods:Fifteen confirmed laryngeal nerve specimens were harvested from five cadavers. Cross-sections were examined under a photomicroscope and morphometric analysis performed.Results:There was a significantly greater number of myelinated fibres than unmyelinated fibres, in both the recurrent laryngeal nerve (p = 0.018) and the superior laryngeal nerve (p = 0.012). There was a significantly greater number of myelinated fibres in the superior laryngeal nerve, compared with the recurrent laryngeal nerve (p = 0.028). However, there was no significant difference in the number of unmyelinated fibres, comparing the two nerves (p = 0.116).Conclusion:These findings support those of previous studies, and provide further evidence against the historical plexus theory of laryngeal nerve morphology. The differences in the degree of myelination, both within and between the human laryngeal nerves, may have clinical consequence regarding recovery of function following nerve injury.

Variability of flowering and 2n pollen production in diploid potatoes under high temperatures

1987 ◽  
Vol 64 (1) ◽  
pp. 35-40 ◽  
Author(s):  
Kathleen G. Haynes ◽  
F. L. Haynes ◽  
William H. Swallow
Keyword(s):  
High Temperatures ◽  
Pollen Production ◽  
2N Pollen

scholarly journals Preliminary morphological and anatomical study of Orthosiphon stamineus

2013 ◽  
Vol 1 (04) ◽  
pp. 01-06 ◽  
Author(s):  
Manaf Almatar ◽  
Zaidah Rahmat ◽  
Faezah Mohd Salleh
Keyword(s):  
Medicinal Plant ◽  
Cross Sections ◽  
Morphological Study ◽  
Developmental Stages ◽  
Anatomical Study ◽  
Medical Application ◽  
Orthosiphon Stamineus ◽  
Phenolics Compounds ◽  
Wide Usage

This study focuses on the characterization of morphological and anatomical traits of Orthosiphon stamineus which belongs to the Lamiaceae family. Orthosiphon stamineus, better known as “Misai Kucing” or “cats whiskers” by the locals, contained active phenolics compounds such as flavanoids. Despite its wide usage as a medicinal plant, information regarding Orthosiphon stamineus specific developmental stages is relatively scarce. Furthermore, to date, no anatomical data of this plant is available. Therefore, this study aims to systematically identify the developmental stages and its anatomy which may provide more insight to its medical application. The result showed some distinct morphological and anatomical characteristics. In the morphological study, it was observed that Orthosiphon stamineus is a herbal shrub with well-developed creeping rootstock. The leaves are simple, green, and arranged in opposite pairs. The stem is approximately 28 cm in height at the stage (12 days). The flowers have long wispy stamens shaped with pale purple color. In anatomical study, the cross sections of the stem for tow stage (32) and (62) days of this plant were examined. All the detailed systematic study of this plant has not worked earlier.

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