Production of total and stainable pollen grains inOlea europaeaL

Grana ◽  
2007 ◽  
Vol 46 (2) ◽  
pp. 85-90 ◽  
Author(s):  
Giuseppe Ferrara ◽  
Salvatore Camposeo ◽  
Marino Palasciano ◽  
Angelo Godini
Keyword(s):  
Pollen Grains ◽  
Stainable Pollen

2n gametes in Solanum commersonii and cytological mechanisms of triplandroid formation in triploid hybrids of Solanum commersonii × Solanum gourlayi

Genome ◽  
1992 ◽  
Vol 35 (5) ◽  
pp. 864-869 ◽  
Author(s):  
R. W. Masuelli ◽  
E. L. Camadro ◽  
A. O. Mendiburu
Keyword(s):  
2N Gametes ◽  
Pollen Grains ◽  
Solanum Commersonii ◽  
Stainable Pollen ◽  
Large Size ◽  
Common Potato ◽  
Aneuploid Chromosome ◽  
The Common ◽  
Bridge Species ◽  
Solanum Gourlayi

Solanum commersonii Dun. (cmm) is a diploid wild species of potential value for potato breeding. Ploidy level manipulations are necessary to cross this species with the common potato. This could be achieved by the use of "bridge" species and sexual polyploidization in which 2n gametes are involved. Eight introductions of cmm were screened for production of (i) diplandroids, through cytological observations confirmed by controlled 4x Solanum acaule Bitt. (acl) × 2x cmm crosses, and (ii) diplogynoids, by controlled 2x cmm × 2x Solanum gourlayi Haw. (grl) crosses. Eleven plants produced 1–3% large size pollen and one plant produced more than 3% of this type of pollen. Twelve triploid and seven tetraploid hybrids were obtained when these plants were used in crosses with acl. On the other hand, 75 triploid hybrids were obtained from the second type of cross. The average pollen stainability in the diplogynoid triploid cmm × grl hybrids was 18.9%, with a range of 2–34.4%. Forty-four to 54.6% of meiocytes with parallel spindles in metaphase II and anaphase II were observed in microsporogenesis of these hybrids. For each clone, the frequency of triplandroids predicted according to the frequency of meiocytes with parallel, fused and tripolar spindles in anaphase II were 52.3, 36.6, and 45.2%, respectively. These values were highly superior to the frequency of triplandroids predicted according to the number of dyads and triads observed, 8.8, 0.7, and 3.9%, respectively. However, triplandroid frequencies predicted according to the frequencies of fused and tripolar spindles agree with the triplandroid frequencies observed. The frequencies of stainable pollen grains are not completely accounted for by the formation of fused and tripolar spindles. In view of the variability encountered in size, it is assumed that a high proportion of gametophytes with aneuploid chromosome numbers are also stainable. A hypothesis is put forward regarding the possible genetic control of triplandroid formation in the diplogynous triploid hybrids analyzed.Key words: 2n gametes, triploid hybrids, spindle orientation, Solanum commersonii Dun.

Effects of Safflower Sterility Genes on the Inflorescence and Pollen Grains

1994 ◽  
Vol 42 (3) ◽  
pp. 325 ◽  
Author(s):  
J Carapetian
Keyword(s):  
Pollen Grains ◽  
Reproductive Organs ◽  
Carthamus Tinctorius ◽  
Female Sterility ◽  
Natural Conditions ◽  
Vegetative Development ◽  
Stainable Pollen ◽  
The Mean ◽  
Pollen Diameter ◽  
Sterility Genes

Three interacting, unlinked, nuclear genes are reported to control the inheritance of male-female sterility in safflower (Carthamus tinctorius L.). In a cross between US-10 cultivar (genotype S(1)S(1)s(2)s(2)s(3)s(3)) and a geographically distant Indian line 57-147 (genotype s(1)s(1)S(2)S(2)S(3)S(3)), F-2 plants segregated 57 fertile:7 sterile. Sterile genotypes set no seed under natural conditions. This study reports the effects of sterility genes on the inflorescence and pollen grains. Floret elongation was limited in sterile plants at bloom. Lengths of florets in the sterile individuals showed a 17% and a 40% reduction one day before and on the day of anthesis, respectively. This resulted in a conspicuous pinched appearance of the capitula. Lack of seed development in sterile plants hindered the expansion of capitula and prevented the dried florets from lying against the imbricate bracts as in normal fertile plants. The percentage pollen stainability was 96.1 in US-10, 87.5 in 57-147, 91.3 in the F-1, 90.5 in fertile F-2, and 1.4 in sterile F-2 plants. However, none of the stainable pollen grains of the sterile F-2 plants was viable. The mean pollen diameter was 53.2 in US-10, 56.3 in 57-147, 53.9 in the F-1, 58.1 in fertile F-2, and 35.8 mu m in sterile F-2 plants. Sterile plants exhibited a greater variation in pollen diameter than the fertile plants. Light and scanning electron microscopy observations revealed the absence of normally sculptured and tricolpate pollen from the sterile plants. The results suggest that the sterility genes have their effects primarily on reproductive organs, but do not hinder vegetative development and growth of sterile plants before they bloom.

Inheritance and microsporogenesis of a synaptic mutant (sy-2) from Solanum commersonii Dun.

1986 ◽  
Vol 28 (4) ◽  
pp. 520-524 ◽  
Author(s):  
S. A. Johnston ◽  
R. W. Ruhde ◽  
M. K. Ehlenfeldt ◽  
R. E. Hanneman Jr.
Keyword(s):  
Chromosome Segregation ◽  
2N Gametes ◽  
Pollen Grains ◽  
Pollen Sterility ◽  
Crossing Over ◽  
2N Pollen ◽  
Solanum Commersonii ◽  
Stainable Pollen ◽  
Tetrad Stage ◽  
Meiotic Mutants

A mutant has been found in diploid Solanum commersonii (2n = 2x = 24) in which no bivalents are formed during microsporogenesis. This trait, a simply inherited recessive, has been designated sy-2. It conditions high levels of pollen sterility through random chromosome segregation at anaphase I. Only the nucleolar-associated chromosomes appear to segregate non-randomly, possibly due to the fusion of the nucleoli as cells near diakinesis. Branched spindle configurations result in multipolar telophase I arrangements, yielding from one to seven pollen grains at the tetrad stage. Most of the stainable pollen produced appears to be 2n. The 2n pollen formed by this mechanism should bear the exact genotype of the parent, since no crossing-over occurs.Key words: Solanum, potato, 2n gametes, mutants (meiotic), mutants (synaptic).

Genome analysis of Elytrigia caespitosa, Lophopyrum nodosum, Pseudoroegneria geniculata ssp. scythica, and Thinopyrum intermedium (Triticeae: Gramineae)

Genome ◽  
1993 ◽  
Vol 36 (1) ◽  
pp. 102-111 ◽  
Author(s):  
Zhi-Wu Liu ◽  
Richard R.-C. Wang
Keyword(s):  
Karyotype Analysis ◽  
Diploid Species ◽  
Pollen Grains ◽  
Root Tip ◽  
Meiotic Pairing ◽  
Tetraploid Species ◽  
Thinopyrum Intermedium ◽  
Male Sterile ◽  
Stainable Pollen ◽  
C Banding

To elucidate the genome constitutions of the tetraploid (2n = 4x = 28) species Elytrigia caespitosa, Lophopyrum nodosum, and Pseudoroegneria geniculata ssp. scythica and the hexaploid (2n = 6x = 42) Thinopyrum intermedium, meiotic pairing was studied in these species as well as 10 hybrids. Karyotype analysis with aceto-orcein stained root-tip cells was performed for the four species and the hybrids of T. bessarabicum with E. caespitosa, P. geniculata ssp. scythica, and T. intermedium. Karyotype analysis by Giemsa C-banding was carried out with the three tetraploid species and the two triploid hybrids involving T. bessarabicum. The species behaved as strict allopolyploids. All hybrids were male sterile with few stainable pollen grains. It is concluded from the results that the three tetraploid species have the genome formula JeJeSS and T. intermedium has the formula JeJeJeJeSS. The chromosomes of the Je and S genomes in these species had C-banding patterns differing from each other and from those of the extant diploid species. Based on these findings, the four species investigated should be placed in the same genus or the same section of a genus. However, new combinations are not proposed at this time pending future taxonomic investigation of the genome constitution of Elytrigia repens (L.) Nevski.Key words: genome, hybrid, meiosis, karyotype, chromosome banding, speciation.

Resolution of Channels in the Exine by Translocation of Colloidal Iron

1971 ◽  
Vol 29 ◽  
pp. 352-353
Author(s):  
John R. Rowley
Keyword(s):  
Phosphate Buffer ◽  
Pollen Development ◽  
Osmium Tetroxide ◽  
Pollen Grains ◽  
Deionized Water ◽  
Colloidal Iron ◽  
Fixed Material ◽  
Epilobium Angustifolium ◽  
Untreated Material ◽  
Microspore Mitosis

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.

Freeze-substitution of rye grass and ragweed pollen grains

1990 ◽  
Vol 48 (3) ◽  
pp. 686-687
Author(s):  
Liza B. Martinez ◽  
Susan M. Wick
Keyword(s):  
Cell Function ◽  
Pollen Grains ◽  
Freeze Substitution ◽  
Cell Types ◽  
Rapid Freezing ◽  
Rye Grass ◽  
Acrylic Resins ◽  
Allergenic Proteins ◽  
Cold Embedding ◽  
Structural Preservation

Rapid freezing and freeze-substitution have been employed as alternatives to chemical fixation because of the improved structural preservation obtained in various cell types. This has been attributed to biomolecular immobilization derived from the extremely rapid arrest of cell function. These methods allow the elimination of conventionally used fixatives, which may have denaturing or “masking” effects on proteins. Thus, this makes them ideal techniques for immunocytochemistry, in which preservation of both ultrastructure and antigenicity are important. These procedures are also compatible with cold embedding acrylic resins which are known to increase sensitivity in immunolabelling.This study reveals how rapid freezing and freeze-substitution may prove to be useful in the study of the mobile allergenic proteins of rye grass and ragweed. Most studies have relied on the use of osmium tetroxide to achieve the necessary ultrastructural detail in pollen whereas those that omitted it have had to contend with poor overall preservation.

Origin of Nectar and Pollen Grains in Honey Produced in Basrah Governorate

2014 ◽  
Vol 27 (1) ◽  
pp. 245-253
Author(s):  
Muhannad R. J. Allamy ◽  
TTaha Y. Al-Edany
Keyword(s):  
Pollen Grains

Pollen morphology of some Tamarix (Tamaricaceae) species of Iran

2020 ◽  
Vol 62 (1-2) ◽  
pp. 151-161
Author(s):  
T. Shagholi ◽  
M. Keshavarzi ◽  
M. Sheidai
Keyword(s):  
North Africa ◽  
Pollen Grains ◽  
Ecological Niches ◽  
Multivariate Statistical Methods ◽  
Multivariate Statistical ◽  
Qualitative And Quantitative ◽  
Petal Length ◽  
Electron Microscopes ◽  
High Level ◽  
Scanning Electron Microscopes

Tamarix L. (Tamaricaceae) is a halophytic shrub in different parts of Asia and North Africa. Taxonomy and species limitation of Tamarix is very complex. This genus has three sections as Tamarix, Oligadenia, and Polyadenia, which are mainly separated by petal length, the number of stamens, the shape of androecial disk and attachment of filament on the androecial disk. As there was no palynological data on pollen features of Tamarix species of Iran, in the present study 12 qualitative and quantitative pollen features were evaluated to find diagnostic ones. Pollen grains of 8 Tamarix species were collected from nature. Pollen grains were studied without any treatment. Measurements were based on at least 50 pollen grains per specimen. Light and scanning electron microscopes were used. Multivariate statistical methods were applied to clarify the species relationships based on pollen data. All species studied showed monad and tricolpate (except some individuals of T. androssowii). Some Tamarix species show a high level of variability, in response to ecological niches and phenotypic plasticity, which make Tamarix species separation much more difficult. Based on the results of the present study, pollen grains features are not in agreement with previous morphological and molecular genetics about the sectional distinction.

Adaptation of electronic scanning microscopy methods for investigation of pollen grains

2020 ◽  
Vol 8 (14) ◽  
pp. 20-28
Author(s):  
Leonora Adamchuk ◽  
◽  
Vladyslav Sukhenko ◽  
Mykola Skoryk ◽  
◽  
...  
Keyword(s):  
Pollen Grains ◽  
Scanning Microscopy

The morphology and ultrastructure of pollen grains of Scutasporites nanuki Utting (Sashiniaceae, Coniferales) from the Permian of the East-European Platform

Palaeobotany ◽  
2012 ◽  
Vol 3 ◽  
pp. 5-11
Author(s):  
A. V. Gomankov ◽  
V. F. Tarasevich
Keyword(s):  
East European Platform ◽  
Central Body ◽  
Pollen Grains ◽  
Irregular Shape ◽  
East European ◽  
Sem And Tem

Dispersed bisaccate pollen grains of Scutasporites nanuki were studied by means of LM, SEM and TEM. Sacci ultrastructure of these pollen grains was rather peculiar. Sacci were like a thin fi lmy fringe attached to the central body near the equator. They were fi lled with sporopollenin elements of irregular shape and various dimensions with equally various cavities between them. Such an ultrastructure is called as spongy. The morphology and ultrastructure of S. nanuki is discussed in the context of the evolution of early conifers.

Sign in / Sign up

Export Citation Format

Share Document