Separation of 2n Potato Pollen from a Heterogeneous Pollen Mixture by Velocity Sedimentation

A method is described for separating large and small pollen effectively from a heterogeneous mixture. This method potentially is applicable to separation of pollen grains of different ploidy levels, since “unreduced” 2n pollen is larger than normal pollen (n); it might then be used to increase the efficiency of a breeding program employing sexual polyploidization and to diminish crossing inefficiencies in interploid crosses.

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INTER-COMPATIBILITY AND PERFORMANCE OF DIPLOID AND DERIVED TETRAPLOID RAPE (BRASSICA CAMPESTRIS L.)

Canadian Journal of Plant Science ◽

10.4141/cjps62-114 ◽

1962 ◽

Vol 42 (4) ◽

pp. 672-680 ◽

Cited By ~ 2

Author(s):

R. K. Downey ◽

J. M. Armstrong

Keyword(s):

Seed Oil ◽

Brassica Campestris ◽

Early Stage ◽

Pollen Grains ◽

2N Pollen ◽

Seed Oil Content ◽

Ploidy Levels ◽

Good Penetration ◽

Selection For ◽

And Performance

Normal diploid and derived tetraploid strains of Brassica campestris were grown in alternate 6-row plots at two locations. Rows of tetraploid rape, spaced 18 inches from diploid rows, were distinctly reduced in yield of seed, oil content and seeds per pod, whereas the seed yield of the diploid was not affected by the proximity of the tetraploid. The yield of the tetraploid increased as the distance from the diploid plots increased.Pollen germination studies and controlled crosses were made within and between ploidy levels. Seven and one-half hours after pollination of 2n and 4n stigmas, n pollen had germinated and made good penetration into stylar tissue whereas pollen tubes were just emerging from 2n pollen grains. It was concluded that pollen from diploid plants had a competitive advantage over pollen from tetraploid plants.No evidence of mature triploid seeds was found on tetraploid plants exposed to n pollen or on diploid plants exposed to 2n pollen. It is suggested that if triploid embryos were formed they aborted at an early stage in development.Comparative yield of seed and oil at 13 locations showed that the derived tetraploid strains yielded less than diploid varieties. This was true despite six to eight generations of selection for seed and oil yield, following synthesis of the tetraploid, and although the strains were isolated in groups according to level of ploidy.

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Use of 2n Giant Pollen to Produce Nonaploid Japanese Persimmon

HortScience ◽

10.21273/hortsci.32.3.441b ◽

1997 ◽

Vol 32 (3) ◽

pp. 441B-441

Author(s):

R. Tao ◽

T. Ohkuma ◽

M. Tamura ◽

A. Sugiura

Keyword(s):

Nuclear Dna ◽

Flow Cytometric Analysis ◽

Nuclear Dna Content ◽

Pollen Grains ◽

2N Pollen ◽

Japanese Persimmon ◽

Normal Pollen ◽

Nylon Mesh ◽

Flow Cytometric ◽

Pollen Diameter

Distribution of pollen diameter of Japanese persimmon cv. Zenjimaru (2n = 6x, × = 15) was determined using pollen grains hydrated with CPW solution supplemented with 0.9 M mannitol. Mean diameter of giant pollen grains (65 μm) was 1.3 times longer than that of normal pollen grains (50 μm). The occurrence of giant pollen was estimated to be about 5% of the pollen population. The hydrated giant pollen grains could be sorted out from normal pollen grains by filtering through a layer of nylon mesh (62 μm). Flow cytometric analysis of nuclear DNA content confirmed that giant pollen was unreduced 2n pollen. 2n giant pollen grains were pollinated to cn. Jiro (2n = 6x) callie and plantlets could be obtained from immature embyros excised from seeds 70 days after pollination.

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Male meiosis and pollen morphology in diploid Indonesian wild bananas and cultivars

The Nucleus ◽

10.1007/s13237-021-00350-7 ◽

2021 ◽

Author(s):

Fajarudin Ahmad ◽

Yuyu S. Poerba ◽

Gert H. J. Kema ◽

Hans de Jong

Keyword(s):

Hybrid Sterility ◽

Pollen Grains ◽

Chromosome Analysis ◽

Male Meiosis ◽

Enzyme Treatment ◽

Unreduced Gamete ◽

Ploidy Levels ◽

Scientific Disciplines ◽

Sterile Pollen ◽

Mother Cells

AbstractBreeding of banana is hampered by its genetic complexity, structural chromosome rearrangements and different ploidy levels. Various scientific disciplines, including cytogenetics, linkage mapping, and bioinformatics, are helpful tools in characterising cultivars and wild relatives used in crossing programs. Chromosome analysis still plays a pivotal role in studying hybrid sterility and structural and numerical variants. In this study, we describe the optimisation of the chromosome spreading protocol of pollen mother cells focusing on the effects of standard fixation methods, duration of the pectolytic enzyme treatment and advantages of fluorescence microscopy of DAPI stained cell spreads. We demonstrate the benefits of this protocol on meiotic features of five wild diploid Musa acuminata bananas and a diploid (AA) cultivar banana “Rejang”, with particular attention on pairing configurations and chromosome transmission that may be indicative for translocations and inversions. Pollen slides demonstrate regular-shaped spores except “Rejang”, which shows fertile pollen grains of different size and sterile pollen grains, suggesting partial sterility and unreduced gamete formation that likely resulted from restitutional meiotic divisions.

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Incompatibility, stamen movement and pollen economy in a heterostyled tropical forest tree, Cratoxylum formosum (Guttiferae)

Proceedings of the Royal Society of London Series B Biological Sciences ◽

10.1098/rspb.1982.0010 ◽

1982 ◽

Vol 214 (1195) ◽

pp. 273-283 ◽

Cited By ~ 22

Keyword(s):

Critical Level ◽

Pollen Grains ◽

Forest Tree ◽

Incompatible Pollen ◽

Insect Visitation ◽

Small Pollen ◽

Evolutionary Step ◽

Novel Method ◽

Compatible Pollinations ◽

Compatible Pollen

Cratoxylum formosum shows all the classical features of a distylic species. The two types are: long-styled plants with short stamens and small pollen grains and short-styled plants with long stamens and large pollen grains. Compatible pollinations are only between the two types; incompatible pollen tubes are inhibited in the style. A significant morphological feature distinguishes Cratoxylum from distylic plants in other families. Instead of having a small number of anthers making well separated narrow discs in the two types, Cratoxylum has many anthers (144) and they are arranged on staminal bundles that produce long cylinders of anthers that partially occupy similar height zones in the two types of flower. A novel method of separation of the two height zones is achieved by the bending of the stamens of the long-styled type when the flower opens, which converts the cylinder to a narrow disc of anthers at the same height as the ‘short’ stigma. The bending coincides with anther dehiscence and is slightly later than the first daily insect visitation. The anthers return to the upright position later in the day, when the pollination is complete. There was a 20-fold difference between the amounts of pollen deposited on the two types of stigmas. The ‘long’ stigmas received 1200 pollen grains per flower, in the ratio of 46 ‘long’ to 54 ‘short’, which is close to the ratio of two types of pollen produced in the population. This random deposition of pollen on ‘long’ stigmas is, however, more than adequate for the 36 seeds produced per flower. ‘Short’ stigmas received only 64 pollen grains per flower, in the ratio of 90 ‘long’ to 10 ‘short’, and several flowers had below the critical level of 36 compatible pollen grains for full seed production. Pollen loads of the pollinating bee, Apis javana , consisted of ‘long’ and ‘short’ pollen on the thorax in the ratio found on the ‘long’ stigma, and on the head of the bee in a ratio close to the 9:1 found on the ‘short ’ stigma. The corbicular loads reflected accurately the pollen of the tree in which the bee was caught. For Cratoxylum the accurate positioning of the anthers of the long-styled plant in relation to the visiting bees head was an important evolutionary step in the effective pollination of the short-styled form, which, at least in this species, is one critical and highly selected feature of the system.

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CYTOLOGY OF 2n POLLEN FORMATION IN DIPLOID ALFALFA, MEDICAGO SATIVA

Canadian Journal of Genetics and Cytology ◽

10.1139/g79-057 ◽

1979 ◽

Vol 21 (4) ◽

pp. 525-530 ◽

Cited By ~ 52

Author(s):

Nicholi Vorsa ◽

E. T. Bingham

Keyword(s):

Medicago Sativa ◽

Seed Set ◽

Pollen Grains ◽

Genetic Constitution ◽

2N Pollen ◽

Diploid Parent ◽

2N Gamete ◽

Medicago Sativa L ◽

Pollen Formation ◽

Mother Cells

Four diploid (2x) clones of alfalfa, Medicago sativa L., which produced good seed set when used as male parents in 4x-2x crosses were selected for study. The 2x clones descended from 2x haploids of cultivated 4x alfalfa. Fertility in the 4x-2x cross was due to the production of pollen with the unreduced chromosome number (2n pollen) from the 2x parent. The cytological mechanism of 2n pollen formation was found to be disorientation of spindles at metaphase II in up to 38% of the pollen mother cells. Thus, both n and 2n pollen were produced by all four diploids examined. Normal spindles at metaphase II were oriented such that they defined the poles of a tetrahedron and resulted in normal tetrads in a tetrahedral arrangement. Disoriented spindles were basically parallel to each other and resulted in formation of dyads and occasionally a triad. Dyads developed into two 2n pollen grains; triads developed into one 2n and two n pollen grains. Since both n and 2n pollen grains are produced by the diploids, they can be maintained as diploids or they can be used as male parents in crosses to tetraploids. The genetic constitution of 2n pollen resulting from parallel spindles is similar to that expected after first division restitution of meiosis and much of the heterozygosity of the diploid parent is conserved in the gametes. The 2n gamete mechanism has potential application in germplasm transfer and in maximizing heterozygosity in tetraploid hybrids.

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Virola dominicana sp. nov. (Myristicaceae) from Dominican amber

Botany ◽

10.1139/cjb-2013-0019 ◽

2013 ◽

Vol 91 (8) ◽

pp. 530-534 ◽

Cited By ~ 6

Author(s):

George Poinar ◽

Royce Steeves

Keyword(s):

New Species ◽

Intraspecific Variation ◽

Pollen Grains ◽

First Record ◽

Western Hemisphere ◽

Dominican Amber ◽

The Family ◽

Small Pollen ◽

Male Flowers ◽

Staminal Column

The Myristicaceae is a member of the early diverging angiosperm order Magnoliales; however, the family is poorly represented by fossil collections. We describe Virola dominicana sp. nov. (Myristicaceae), the first record of fossilized Myristicaceae flowers, from mid-Tertiary (45–15 million years ago) Dominican amber. The description is based on 24 male flowers in 17 pieces of amber, thus providing some indication of intraspecific variation, including a two-tepaled flower. Diagnostic characters of the new species are the long-simple or few-branched trichomes on the perianth margins, the small pollen grains, and a short staminal column. These fossils also show co-occurring insects, some of which could be Virola pollinators. It is speculated that V. dominicana disappeared from Hispaniola during the Pliocene–Pleistocene cooling events leaving no native members of the Myristicaceae in this region today. Additionally, these fossils demonstrate that Myristicaceae was present in the Western Hemisphere during the mid-Tertiary.

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Morphological diversity of pollen from selected species of the genus Taraxacum, according to their ploidal level

Acta Agrobotanica ◽

10.5586/aa.2008.008 ◽

2012 ◽

Vol 61 (1) ◽

pp. 65-69 ◽

Cited By ~ 2

Author(s):

Jolanta Marciniuk ◽

Anna Rudzińska-Langwald

Keyword(s):

Pollen Grains ◽

Morphological Diversity ◽

Great Variability ◽

2N Pollen ◽

Regular Type ◽

Unknown Number ◽

Species Being ◽

The Way

The study of the morphology of pollen concerned eight species of the genus Taraxacum. Seven types were chosen with a different number of chromosomes belonging to the section Palustria: Taraxacum paucilobum 2n = 3x = 24, T. subdolum 2n = 3x =24, T. subpolonicum 2n =3x = 24, T. vindobonense 2n = 4x = 32, T. trilobifolium 2n = 4x = 32, T. mendax 2n = 5x = 40, T. portentosum 2n =? and one type from the section Obliqua - T. platyglossum 2n =?. Pollen from all the examined species was observed by SEM microscopy. A distinct relation exists between the morphology of pollen and the way of reproduction. Pollen of triploidal species, being compulsory apomicts, is characterized by a great variability of the size and a high percentage of deformed pollen grains. Tetraploids, being optional apomicts, produce regular pollen with a relatively even size. The regular type of pollen in pentaploidal Taraxacum mendax and in species with an unknown number of chromosomes (Taraxacum portentosum and T. platyglossum) suggests that these taxa are optional apomicts.

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A comparison of progeny from diallel crosses of diploid potato with regard to the frequencies of 2n-pollen grains

Euphytica ◽

10.1007/bf00037114 ◽

1995 ◽

Vol 92 (3) ◽

pp. 313-320

Author(s):

Qu Dongyu ◽

Zhu Dewei ◽

M. S. Ramanna ◽

E. Jacobsen

Keyword(s):

Pollen Grains ◽

Diploid Potato ◽

2N Pollen ◽

Diallel Crosses

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Pollen viability and germination in some neotropical aroids

Botany ◽

10.1139/b07-110 ◽

2008 ◽

Vol 86 (1) ◽

pp. 98-102 ◽

Cited By ~ 5

Author(s):

Denis Barabé ◽

Karine Lavallée ◽

Marc Gibernau

Keyword(s):

Pollen Viability ◽

Pollen Grains ◽

Total Loss ◽

Small Pollen

Pollen viability and germination were observed in six species of neotropical Araceae. In Anaphyllopsis americana (Engl.) A. Hay, 50% of pollen grains remain viable after 70 h following dehiscence, and it takes over 210 h for total loss of viability to occur. In Montrichardia arborescens (L.) Schott, approximately 50% of pollen grains are not viable after 24 h, and no germination occurs after 36 h. Monstera adansonii Schott and Philodendron pedatum (Hook.) Kunth have the lowest initial pollen viability (40%–55%) and lose half of this viability after approximately 30 h. Pollen grains of Monstera adansonii remain viable for at least 60 h and that of P. pedatum for approximately 40 h, and constitute another group with a similar viability pattern. In Philodendron melinonii Brongn. ex Regel and Philodendron solimoesense A.C. Sm., pollen loses 50% of its viability after 24 h, but remains viable for at least 48 h. The percentage of viability decreases in a pattern from species having a long flowering cycle and small pollen grains (A. americana) to species with a short flowering cycle and large pollen grains (M. arborescens).

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