A separate control for frequency and within-bivalent distribution of chiasmata in rye (Secale cereale L.)

Genome ◽  
1987 ◽  
Vol 29 (3) ◽  
pp. 419-424 ◽  
Author(s):  
V. Lein ◽  
T. Lelley
Keyword(s):  
Secale Cereale ◽  
Chiasma Frequency ◽  
Positional Distribution ◽  
Pollen Grains ◽  
Female Parent ◽  
Close Correlation ◽  
Strong Negative Correlation ◽  
Pollen Mother Cells ◽  
Chiasma Distribution ◽  
Mother Cells

Six genetically different inbred genotypes of spring-type rye Secale cereale with differences in the average number and in the positional distribution of chiasmata were used in this study. The line with the lowest chiasma frequency was chosen as the female parent and crossed with the other five lines. Parental, F1, and F2 data were collected on chiasma number and on chiasma distribution between and within bivalents. Evidence for a polygenic control of both phenomena was found. Chiasma distribution between bivalents within pollen mother cells obviously follows a binomial distribution. This is effected by a mechanism that prevents the formation of a second chiasma on a chromosome arm as long as chromosome arms without chiasma remain; i.e., with 14 chiasmata seven ring bivalents will generally be formed. This mechanism causes a very strong negative correlation between frequency and between-cell variance of chiasmata. The number of chiasmata is independent of their position within the bivalents. A very close correlation between the number of pollen mother cells without univalents and the number of fertile pollen grains was found. Key words: inbred rye, genetic control, chiasma frequency, chiasma distribution, heterosis.

A natural first-generation hybrid between Rorippa barbareaefolia and R. islandica

1968 ◽  
Vol 46 (8) ◽  
pp. 1079-1081
Author(s):  
Gerald A. Mulligan ◽  
A. E. Porsild
Keyword(s):  
First Generation ◽  
Female Parent ◽  
Yukon Territory ◽  
Male Parent ◽  
Male Sterile ◽  
Pollen Mother Cells ◽  
Mother Cells ◽  
Generation Hybrid

All the seeds taken from a fruiting specimen of Rorippa barbareaefolia (2n = 16) growing in the Yukon Territory produced plants with 24 somatic chromosomes. These plants were first-generation hybrids between R. barbareaefolia (2n = 16) and R. islandica (2n = 23). The female parent, R. barbareaefolia, was male sterile. Pairing configurations in pollen mother cells of these first generation hybrids suggested that the male parent, R. islandica, was autotetraploid.

scholarly journals Studies on the Morphology, Ontogeny and Embryology of the Flowers of Hedycarya Arborea J.R. et G. Forst. (Subfamily Monimioideae) and Laurelia Novae-Zelandiae A. Cunn. (Subfamily Atherospermoideae) of the Family Monimiaceae

2021 ◽  
Author(s):  
◽  
Frederick Bruce Sampson
Keyword(s):  
Generative Cell ◽  
Embryo Sac ◽  
Pollen Grains ◽  
Tetrad Stage ◽  
Pollen Mother Cells ◽  
The Family ◽  
Long Time ◽  
External Part ◽  
Mother Cells ◽  
And Function

<p>The inflorescences, flowers and the vascularization of floral parts of Hedycarya arborea and Laurelia novae-zelandiae were described and comparisons made with other members of the family in an attempt to determine the basic types of inflorescences, flowers and floral vascularization in the family. The vegetative, inflorescence and floral meristems of the two genera were compared. It was concluded that the vegetative apices of both had the tunica-corpus configuration typical of many other woody Ranales and other orders. The inflorescence apices were quite similar to the vegetative ones. The young floral apices are in a state of transition from a tunica-corpus to a mantle-core configuration and older floral apices had the mantle-core configuration, which is typical of the floral apices of many woody Ranales. Unusual features of the floral apices of Hedycarya and Laurelia were the lack of a pronounced rib meristem and the occurrence of relatively frequent divisions within vacuolate cells of the core. The ontogeny of the stamens of Hedycarya and Laurelia was described and comparisons were made. In both genera the micro-sporangium developed in a similar fashions: in Hedycarya 5-6 wall layers are formed inside the epidermis; in Laurelia there are 3-5 layers. Both genera had a typically thickened endothecium and a tapetum of the secretory type in which the tapetal cells become binucleate during the first meiotic division of the pollen mother cells. In Hedycarya the meiotic divisions of the pollen mother cells are of the successive type in which walls form by means of centrifugal cell plates Pollen grains remain in permanent tetrads in this genus. In Laurelia wall formation at the end of meiosis is of a modified simultaneous type, which may not have been hitherto described in the literature. Pollen grains are not in permanent tetrads. When the first division occurs in each microspore in Hedycarya, all four cells of a tetrad are at the same stage of division and the generative cell is cut off towards the distal face of the grain. Each microspore is in the two celled condition when shed. It was deduced that the generative cell is cut off against what represents a radial wall of the grain (with reference to the tetrad stage) in Laurelia. Pollen is shed in either the two or three celled condition. Comparisons were made with the development of microsporangia and male gametophytes in other woody Ranales. A study was made of the ontogeny, structure and function of the staminal appendages of Laurelia. It was found that the appendages function as nectaries, the nectar being predominantly sucrose. After a discussion of the various theories as to the morphological nature of the staminal appendages of the Laurales, it was concluded that they are morphologically staminodes. The carpels of Hedycarya and Laurelia have a basically similar ontogeny in which, as in the Lauraceae, the terminal stigmatic region develops from a solid terminal meristem in contrast to many woody Ranales in which the stigma-consists of crests which surround the external part of the cleft of the carpel. The ovules of Hedycarya and Laurelia resemble those of most other woody Ranales in being bitegmic, crassinucellate and anatropous with a monosporic 8-nucleate embryo sac of the Polygonum type. Both linear and T-shaped megaspore tetrads were found in the two genera. Laurelia has pseudocarps which develop after anthesis and enclose plumose achenes, but in Hedycarya the fruits are drupes. It was concluded that Laurelia and Hedycarya belong to two subfamilies which have been separated from each other for a long time and have undergone considerable evolution in different directions. It was also concluded that the Monimiaceae are closely related to the Lauraceae.</p>

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.

Effect of auxins and cytokinins upon the start of meiosis in cultured anthers of rye (Secale cereale L.)

1985 ◽  
Vol 27 (6) ◽  
pp. 759-765 ◽  
Author(s):  
J. Rueda ◽  
A. M. Vázquez
Keyword(s):  
Anther Culture ◽  
Plant Hormones ◽  
Secale Cereale ◽  
Meiotic Division ◽  
Basic Medium ◽  
Differential Capacity ◽  
Pollen Mother Cells ◽  
Secale Cereale L ◽  
Mother Cells

Anthers of rye excised at premeiotic interphase were cultured in vitro on a basic medium and on a series of auxin- and cytokinin-containing media to ascertain the effect of these plant hormones upon the start of meiosis. Only in the hormone-containing media was it possible to find anthers in which pollen mother cells had started the meiotic division. The different hormones and concentrations tested exhibited a differential capacity to induce the start of meiosis, the percentages of anthers with pollen mother cells in meiosis varying from 0% in one medium to more than 60% in two other media. In some media, pollen mother cells were able to complete the whole meiotic division, while in others they were arrested at different stages of meiosis.Key words: Secale cereale, meiosis induction, anther culture, plant hormones.

Origin of B chromosomes in cultivated rye

Genome ◽  
1995 ◽  
Vol 38 (2) ◽  
pp. 307-312 ◽  
Author(s):  
K. Niwa ◽  
S. Sakamoto
Keyword(s):  
Secale Cereale ◽  
Natural Populations ◽  
B Chromosomes ◽  
Standard Type ◽  
Monophyletic Origin ◽  
Pollen Mother Cells ◽  
Somatic Metaphase ◽  
Pistillate Parent ◽  
Mother Cells ◽  
Cytogenetic Relationship

Cultivated rye (Secale cereale) and its weedy relative (S. segetale) carry B chromosomes. The B chromosomes are known to be morphologically alike at somatic metaphase and they are of the standard type in natural populations. To clarify the cytogenetic relationship between the standard B chromosomes of S. cereale and those of S. segetale, we made four crosses between Afghan S. segetale with two standard B chromosomes as a pistillate parent and Turkish, Iranian, Korean, and Japanese S. cereale, all with two standard B chromosomes as pollen parents. We observed the pairing of B chromosomes at diakinesis in pollen mother cells in all F1 hybrids with four standard B chromosomes, two from each of the pistillate and the pollen parents. The degree of pairing of B chromosomes in all F1 hybrids with four standard B chromosomes was similar to or somewhat lower than, that in parental strains with four standard B chromosomes. These results showed that the standard B chromosomes in S. segetale from Afghanistan are homologous with those in S. cereale from Turkey, Iran, Korea, and Japan. We therefore propose monophyletic origin of the standard B chromosomes in S. segetale and S. cereale.Key words: Secale, B chromosomes, origin, cultivated rye, weedy rye.

The duration of meiosis in pollen mother cells of wheat, rye and Triticale

1971 ◽  
Vol 178 (1052) ◽  
pp. 259-275 ◽  
Keyword(s):  
Triticum Aestivum ◽  
Dna Synthesis ◽  
Secale Cereale ◽  
Sampling Methods ◽  
Tritiated Thymidine ◽  
Pollen Mother Cells ◽  
Mother Cells

The duration of meiosis and its stages at 20 °C has been determined in wheat ( Triticum aestivum 2 n = 6 x = 42), in rye ( Secale cereale 2 n = 14) and in Triticale (2 n = 8 x = 56) by sampling methods and by timing the intervals between the pre-meiotic DNA synthesis and meiotic stages following the incorporation of tritiated thymidine. The results from all the methods used were in general agreement. Meiosis takes about 24 h in wheat, 21 h in Triticale and about 51 h in rye. The lengths of the meiotic stages relative to that of the division correspond reasonably well in the three forms studied but zygotene and pachytene were much longer in rye than in wheat and Triticale .

scholarly journals Timing of Reproductive Organs Maturity in Proterandrous Malva sylvestris L.

2017 ◽  
Vol 9 (2) ◽  
pp. 287-295
Author(s):  
Aslihan ÇETİNBAŞ-GENÇ ◽  
Meral ÜNAL
Keyword(s):  
Flower Development ◽  
Pollen Grains ◽  
Reproductive Organs ◽  
Floral Meristem ◽  
Pollen Mother Cells ◽  
Malva Sylvestris ◽  
Nucellar Tissue ◽  
Female Phase ◽  
Mother Cells ◽  
Pollen Sacs

Flower development of protandrous species Malva sylvestris L. was divided into 12 stages, as revealed by applying histological and scanning electron microscope techniques. Flower development started with the conversion of apical meristem into floral meristem. Initiation of male organ primordia started before that of female organ. Five rounded structures called corolla/androecium units differentiated from floral meristem, on which stamen primordia emerged. When pollen mother cells exist in the pollen sacs, initiation of carpels starts from floral meristem. Concurrent with the termination of meiosis in pollen mother cells, ten loculed ovary comed in view. Simultaneously with the occurrence of vacuoleted pollen grains, megaspore mother cell becomes visible in the nucellar tissue. Concominant with the existence of two celled-pollen grains, the style was formed and ovule becomes anatropous. When pollen grains are shed in male phase, ten branched stigma appeared on the upper part of the style, but receptive surface was not fully formed to accept pollen grains. Female phase is characterized by the opening of stigmatic branches with papillate receptive surface. Timing of reproductive organs maturity overlapped for a while, thus, the reproductive stragey of M. sylvestris was incomplete proterandry. 

Genetically controlled desynapsis in diploid Critesion violaceum and its hybrids with autotetraploid Psathyrostachys juncea

1984 ◽  
Vol 26 (5) ◽  
pp. 532-537 ◽  
Author(s):  
Richard R-C. Wang
Keyword(s):  
Chromosome Pairing ◽  
Chiasma Frequency ◽  
Intergeneric Hybrid ◽  
Dosage Effect ◽  
The Other ◽  
Pollen Mother Cells ◽  
Psathyrostachys Juncea ◽  
Self Pollination ◽  
Meiotic Irregularities ◽  
Mother Cells

Segregation for chiasma frequency was observed in the progeny of a diploid (2n = 14) Critesion violaceum strain following self-pollination. One S1 plant had normal metaphase pairing with an average of 0.43I + 6.78II, giving a high chiasma frequency, 12.03 per cell. The other S1 plant averaged 7.89I + 3.08II and a low chiasma frequency, 3.47 per cell. Examination of pollen mother cells at early prophases revealed that chromosome pairing was not totally prevented. It was concluded that desynapsis was responsible for the meiotic irregularities observed in the variant progeny. The same phenomena were observed in F1 hybrids of the cross between diploid C. violaceum and an induced autotetraploid (2n = 28), Psathyrostachys juncea. The normal F1 hybrid had a chiasma frequency of 12.81, but the desynaptic hybrid had a chiasma frequency of 6.94. A dosage effect of the desynaptic gene, which was probably recessive, was suggested. The implications and significance of this discovery are discussed.Key words: asynapsis, chiasma, meiosis, intergeneric hybrid.

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