Differential effects of specific chromosomal deficiencies on the development of the maize pollen grain

Genome ◽  
1991 ◽  
Vol 34 (4) ◽  
pp. 579-594 ◽  
Author(s):  
B. Kindiger ◽  
J. B. Beckett ◽  
E. H. Coe Jr.
Keyword(s):  
Male Gametophyte ◽  
Pollen Grain ◽  
Developmental Changes ◽  
Normal Male ◽  
Microspore Development ◽  
Pollen Mitosis ◽  
Maize Pollen ◽  
Differential Effects ◽  
Chromosome Arm ◽  
First Pollen Mitosis

A study was made of the differential effects of specific chromosomal deficiencies on the development of the maize pollen grain. Twenty-six B–A translocations involving 17 of the 20 chromosome arms were used to produce hypoploid plants in which one half of the microspores had a predictable chromosomal deletion. Breakpoints of the translocations were proximally located in most cases, although some were more distal. Deficient and normal male gametophytes from these hypoploids were studied cytologically to characterize developmental changes. Generally, loss of part of a chromosome arm caused abnormal microspore development, a slowing of the normal mitotic or developmental processes in the male gametophyte, or a termination of development. Slowing of development was observed as early as the quartet stage in deficient microspores from TB-1Sb and TB-9Sd hypoploids, while in others the developmental delay occurred later, mostly during the first pollen mitosis. The abnormal or blocked development associated with other deficiencies began as early as the quartet stage in deficient microspores of TB-1La hypoploids and as late as the first mitotic telophase in those of TB-6Lb, TB-6Lc, TB-9La, and TB-9Lc. The developmental modifications induced by the diverse deficiencies are dependent on the particular segment lost, demonstrating that components of normal microspore development identified in this study are controlled by genes located in specific parts of the genome.Key words: pollen, gametophyte, deletion, B–A translocations.

Maize microsporogenesis

Genome ◽  
1989 ◽  
Vol 32 (2) ◽  
pp. 232-244 ◽  
Author(s):  
Ming T. Chang ◽  
M. Gerald Neuffer
Keyword(s):  
Zea Mays ◽  
Zea Mays L ◽  
Developmental Stages ◽  
Morphological Changes ◽  
Pollen Mitosis ◽  
Maize Pollen ◽  
Maize Tassel ◽  
Cytological Features ◽  
Second Pollen Mitosis ◽  
First Pollen Mitosis

The use of maize (Zea mays L.) pollen for basic scientific research has been well documented, but the progression of clear cytological features of maize microsporogenesis has not been fully documented. This study was undertaken to identify cytologically the different developmental stages of maize pollen and to correlate them with morphological features of the developing maize tassel. Morphological changes in the length of the tassel, floret, and anther were recorded and correlated with six cytologically defined stages of microsporogenesis: premeiosis, meiosis, uninucleate stage, first pollen mitosis, second pollen mitosis, and mature pollen.Key words: cytogenetics, gametophyte, maize, microsporogenesis, pollen.

Reproduction Multitasking: The Male Gametophyte

2021 ◽  
Vol 72 (1) ◽  
Author(s):  
Said Hafidh ◽  
David Honys
Keyword(s):  
Male Gametophyte ◽  
Cell Communication ◽  
Embryo Sac ◽  
Pollen Grain ◽  
Wall Structure ◽  
Annual Review ◽  
Publication Date ◽  
Developmental Phase ◽  
Double Fertilization ◽  
Male Gametes

The gametophyte represents the sexual phase in the alternation of generations in plants; the other, nonsexual phase is the sporophyte. Here, we review the evolutionary origins of the male gametophyte among land plants and, in particular, its ontogenesis in flowering plants. The highly reduced male gametophyte of angiosperm plants is a two- or three-celled pollen grain. Its task is the production of two male gametes and their transport to the female gametophyte, the embryo sac, where double fertilization takes place. We describe two phases of pollen ontogenesis—a developmental phase leading to the differentiation of the male germline and the formation of a mature pollen grain and a functional phase representing the pollen tube growth, beginning with the landing of the pollen grain on the stigma and ending with double fertilization. We highlight recent advances in the complex regulatory mechanisms involved, including posttranscriptional regulation and transcript storage, intracellular metabolic signaling, pollen cell wall structure and synthesis, protein secretion, and phased cell–cell communication within the reproductive tissues. Expected final online publication date for the Annual Review of Plant Biology, Volume 72 is May 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

Reevaluation of the Identification of Ancient Maize Pollen from Alabama

1997 ◽  
Vol 62 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Mary Eubanks
Keyword(s):  
Zea Mays ◽  
North America ◽  
Sample Size ◽  
Pollen Grain ◽  
Eastern North America ◽  
Maize Pollen ◽  
Maize Agriculture ◽  
Positive Identification ◽  
Poaceae Pollen

Fearn and Liu (1995) reported positive identification of a large Poaceae pollen grain recovered from a lake bed core in Alabama dating to 3500 B.P. as Zea mays. Reinterpretation of old data and new data reported here indicate this identification is questionable. Review of the evidence at hand indicates the most likely identification of the pollen grain in question is Tripsacum, although it could be primitive maize, teosinte, or Zea “indiana,” a hybrid between Tripsacum and teosinte. Until the sample size is expanded and a firm identification can be made, caution is urged in interpretations about the significance of this find for early maize agriculture in eastern North America.

Extrême précocité et conditions thermiques du développement apical et floral chez Claytonia caroliniana var. caroliniana

1985 ◽  
Vol 63 (9) ◽  
pp. 1516-1520 ◽  
Author(s):  
Miroslav M. Grandtner ◽  
Camille Gervais
Keyword(s):  
Sugar Maple ◽  
Floral Development ◽  
Growth Period ◽  
Chromosomal Anomalies ◽  
Cellular Activity ◽  
Seed Setting ◽  
Pollen Mitosis ◽  
Aerial Portion ◽  
Second Pollen Mitosis ◽  
First Pollen Mitosis

The apical and floral development of Claytonia caroliniana var. caroliniana has been studied concurrently with soil temperature, in a sugar maple forest of the Stoneham mountain, Québec. Apical cellular activity begins early in May, while the flowering stems of the year are present. At the beginning of July, external apical development becomes visible. In the first days of August, 9 months before flowering, the foliar and floral structures of the next year are already present in the soil. Meiosis takes place at the beginning of October and first pollen mitosis follows shortly after, in the middle of the same month. From that time, well developed individuals, without chlorophyll, are present just under the litter. They can occasionally turn green and reach the upper surface of the litter in November or December, where they will spend wintertime under the snow, at a temperature oscillating between 0 and −4 °C. This behaviour is quite close to the survival strategy of hemicryptophytes. The active epigeous growth period begins in the middle of April, with the melting of snow. Second pollen mitosis and flowering take place at this time, rapidly followed by seed setting, dissemination, and destruction of the aerial portion of the plant. Cytoecological investigations to study possible influence of environmental factors on chromosomal anomalies in primordia should thus be conducted during the year preceding the flowering of Claytonia.

Male gametophyte development in monosomics of maize

Genome ◽  
1989 ◽  
Vol 32 (1) ◽  
pp. 155-164 ◽  
Author(s):  
Zuo-Yu Zhao ◽  
David F. Weber
Keyword(s):  
Gene Dosage ◽  
Male Gametophyte ◽  
Developmental Differences ◽  
Chromosome 1 ◽  
Normal Male ◽  
Chromosome 2 ◽  
Developmentally Delayed ◽  
Gametophyte Development ◽  
Male Gametophyte Development ◽  
Maize Plants

The development of male gametophytes in diploid and monosomic-1, -2, -3, -4, -6, -7, -8, -9, and -10 maize plants was characterized. Developmental differences due to nullisomy in the gametophyte were evaluated by comparing the development of haploid and nullisomic microspores formed by monosomic plants, while differences due to gene dosage in the sporophyte were evaluated by comparing the development of haploid microspores in monosomic plants with those in diploids. These analyses show that (i) male gametophytes nullisomic for the chromosomes analyzed are developmentally delayed and eventually abort; (ii) male gametophytes nullisomic for chromosome 2 or 6 can reach the first mitosis, but those nullisomic for chromosomes 1, 3, 4, 7, 8, 9, or 10 do not reach the first division; and (iii) monosomy of chromosome 1, 2, 3, 4, 6, 7, 8, or 9 interferes with normal male gametophyte development, and monosomic-2 and -9 plants specifically cannot support pollen maturation.Key words: aneuploidy, monosome, nullisome, microspore, r-X1, deficiency.

scholarly journals Abnormal Microspore Development Leads to Pollen Abortion in a Seedless Mutant of ‘Ougan’ Mandarin (Citrus suavissima Hort. ex Tanaka)

2007 ◽  
Vol 132 (6) ◽  
pp. 777-782 ◽  
Author(s):  
Zhiyong Hu ◽  
Min Zhang ◽  
Qigen Wen ◽  
Jie Wei ◽  
Hualin Yi ◽  
...  
Keyword(s):  
Pollen Viability ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Mature Pollen ◽  
Abnormal Development ◽  
Microspore Development ◽  
Wild Type ◽  
Pollen Abortion ◽  
Tetrad Stage ◽  
In The Wild

Seedlessness is of commercial importance in citrus (Citrus L.). Seedless ‘Ougan’ mandarin (C. suavissima) was selected from a bud sport mutation that occurred in ‘Ougan’ mandarin. We analyzed their pollen viability through KI-I2 and FDA staining, and examined the anthers of wild-type (seedy) and seedless mutant ‘Ougan’ mandarin using histological and cytochemical methods to characterize the process of pollen development. No pollen fertility was detected in this mutant. Pollen abortion in anthers of the mutant occurred at the tetrad stage of microspore development, and almost all the tetrads were abnormal. The mutant had heterogeneous microspore populations, including monads, dyads, triads, tetrads, and polyads in the same microsporangium. Pollen grain number per anther of the mutant was 21.9% less than the wild type. Morphology of mature pollen grains using SEM showed that the shape of mature pollen grains from both wild type and mutant is similar, but the microsporangia of the latter contained pollen grains of more variable sizes. At the early mature pollen grain stage, abundant starch grains and lipids appeared in the wild type's pollen, but fewer amounts were observed in the mutant. Moreover, the tapetal cells of the wild type accumulated lipids, but not those of the mutant. Results indicated that the abnormal development of the microspore led to pollen abortion in the mutant, and this could be the reason for its seedlessness. However, the genetic reasons for the aberrant tetrads are not clear and are under investigation.

Biology of Australian seagrasses: Pollen development and submarine pollination in Amphibolis antarctica and Thalassodendron ciliatum (Cymodoceaceae)

1978 ◽  
Vol 26 (3) ◽  
pp. 265 ◽  
Author(s):  
SC Ducker ◽  
JM Pettitt ◽  
RB Knox
Keyword(s):  
Acid Phosphatase ◽  
High Resolution ◽  
19Th Century ◽  
Aquatic Plants ◽  
Mature Pollen ◽  
Pollen Mitosis ◽  
Electron Microscopic ◽  
First Pollen Mitosis ◽  
Thalassodendron Ciliatum ◽  
Submarine Pollination

Development of the filiform pollen of the sea nymph Arnphibolis antarctica (Labill.) Sonder & Aschers. ex Aschers. has been characterized by high resolution light and electron microscopic methods. First pollen mitosis occurs at the end of the young spore period immediately preceding the vacuolate period, in contrast to many terrestrial pollens. Mature pollen is trinucleate, and is spirally coiled within the anther. The mature pollen wall shows a positive reaction for acid phosphatase like the intine of terrestrial pollens but is devoid of the outer exine layer, as judged by light and electron microscopic evidence. Development and arrangement of Thalassodendron ciliatum (Forssk.) Den Hartog pollen are similar. The adaptation of the pollen of aquatic plants for submarine pollination is reviewed in the light of evidence from 18th and 19th century work.

Relative rate of development of aneuploid and euploid microspores in a tertiary trisomic of rye, Secale cereale L.

1985 ◽  
Vol 27 (4) ◽  
pp. 393-398 ◽  
Author(s):  
J. Janse
Keyword(s):  
Mitotic Index ◽  
Secale Cereale ◽  
Time Scale ◽  
Relative Rate ◽  
Pollen Mitosis ◽  
Rate Of Development ◽  
Pollen Mother Cells ◽  
Secale Cereale L ◽  
First Pollen Mitosis ◽  
Mother Cells

Meiotic configurations were studied in pollen mother cells of a tertiary trisomic of rye. Chains of five and chains of three, in alternate orientation, were the most frequent configurations. Assuming loss of univalents in anaphase I or single chromatids in anaphase II, a total of 58.1% of the viable gametes resulting after meiosis were expected to contain the normal haploid complement, whereas 41.9% were expected to have the translocated chromosome in addition. The percentages of uninucleate and binucleate microspores in anthers containing dividing microspores provided a time scale for the development of euploid and aneuploid spores during first pollen mitosis. Microspores containing the extra translocated chromosome tended to divide at a later stage than euploid microspores. The slower development was also illustrated by the course of the mitotic index of both types. It was found that 58.1% of all microspores passing through pollen mitosis contained seven chromosomes and 41.9% contained eight chromosomes, which means that up to the end of first pollen mitosis aneuploid spores were not lost significantly more than euploid spores. It is likely that the delay in development already starts immediately after meiosis.Key words: rye, tertiary trisomic, euploid microspores, aneuploid microspores, rate of development.

Elimination of hop latent viroid upon developmental activation of pollen nucleases

2008 ◽  
Vol 389 (7) ◽  
Author(s):  
Jaroslav Matoušek ◽  
Lidmila Orctová ◽  
Josef Škopek ◽  
Karel Pešina ◽  
Gerhard Steger
Keyword(s):  
Mature Pollen ◽  
Developmental Expression ◽  
Pollen Mitosis ◽  
Rt Pcr ◽  
Sequence Comparisons ◽  
Pollen Maturation ◽  
First Pollen Mitosis ◽  
Microspore Stage ◽  
Germinating Pollen

Abstract Hop latent viroid (HLVd) is not transmissible through hop generative tissues and seeds. Here we describe the process of HLVd elimination during development of hop pollen. HLVd propagates in uninucleate hop pollen, but is eliminated at stages following first pollen mitosis during pollen vacuolization and maturation. Only traces of HLVd were detected by RT-PCR in mature pollen after anthesis and no viroid was detectable in in vitro germinating pollen, suggesting complete degradation of circular and linear HLVd forms. The majority of the degraded HLVd RNA in immature pollen included discrete products in the range of 230–100 nucleotides and therefore did not correspond to siRNAs. HLVd eradication from pollen correlated with developmental expression of a pollen nuclease and specific RNAses. Activity of the pollen nuclease HBN1 was maximal during the vacuolization step and decreased in mature pollen. Total RNAse activity increased continuously up to the final steps of pollen maturation. HBN1 mRNA, which is abundant at the uninucleate microspore stage, encodes a protein of 300 amino acids (34.1 kDa, isoeletric point 5.1). Sequence comparisons revealed that HBN1 is a homolog of S1-like bifunctional plant endonucleases. The developmentally activated HBN1 and pollen ribonucleases could participate in the mechanism of HLVd recognition and degradation.

The RSS system of unidirectional cross-incompatibility in maize. 2. Cytology

Genome ◽  
1992 ◽  
Vol 35 (4) ◽  
pp. 560-564
Author(s):  
Abdul Rashid ◽  
Peter A. Peterson
Keyword(s):  
Pollen Tube ◽  
Female Parent ◽  
Pollen Tubes ◽  
Pollen Grain ◽  
Maize Pollen ◽  
Transmitting Tract ◽  
Incompatible Pollination ◽  
Recessive Genes ◽  
Maize Genetics ◽  
Incompatibility Reaction

In 1975, a number of genetic lines discovered in our maize genetics nursery in Ames, Iowa, showed unidirectional cross-incompatibility. Later, it was found that this unidirectional cross-incompatibility is controlled by three recessive genes. One locus (cif) controls the incompatibility reaction in the female tissue and the other two (cim1 and cim2) control the incompatibility reaction in the pollen grain. The cross is incompatible only when the female parent is homozygous recessive for the cif and the male parent is homozygously recessive for the cim1 as well as the cim2 locus. Cytological studies of this unidirectional cross-incompatibility show that the site of the incompatibility reaction occurs after the entry of the pollen tubes into the transmitting tract of the incompatible silks. Between 12 and 24 h after pollination, the incompatible pollination is characterized by the swelling and bursting of pollen tubes at the tip, after which pollen tube growth stops.Key words: maize, pollen tube, cross-incompatibility.

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