Meiotic metaphase I to telophase II as the most responsive stage during microspore development for callus induction in tomato (Solanum lycopersicum) anther cultures

2005 ◽  
Vol 27 (4) ◽  
pp. 675-685 ◽  
Author(s):  
José M. Seguí-Simarro ◽  
Fernando Nuez
Keyword(s):  
Solanum Lycopersicum ◽  
Callus Induction ◽  
Meiotic Metaphase ◽  
Microspore Development ◽  
Anther Cultures ◽  
Metaphase I

Cytokinin-cytokinin interaction ameliorates the callus induction and plant regeneration of tomato (Solanum lycopersicum Mill.)

2012 ◽  
Vol 60 (1) ◽  
pp. 47-55 ◽  
Author(s):  
A. Ali ◽  
T. Yossef ◽  
A. El-Banna
Keyword(s):  
Plant Regeneration ◽  
Solanum Lycopersicum ◽  
Callus Induction ◽  
Ms Medium ◽  
Regeneration System ◽  
Benzyl Adenine ◽  
Cotyledon Explants ◽  
Tomato Genotypes ◽  
Number Of Shoots

The present study was carried out for developing an efficient in vitro callus induction and plant regeneration system in four different tomato genotypes (Solanum lycopersicum Mill., previous name: Lycopersicon esculentum), Advantage II, Edkawy, Castle Rock and Super Strain B, using hypocotyl and cotyledon explants. The effects of two cytokinins, BA (benzyl adenine) and Kin (kinetin), on callus induction and plant regeneration frequency were investigated when added to MS medium in combination at varying concentrations. All concentrations of the two cytokinins were suitable for callus induction and plant regeneration. The frequency of callus induction and plant regeneration from both cotyledon and hypocotyl explants reached 100% for all tested genotypes. Cotyledons produced a higher average number of shoots per explants than hypocotyls for all the genotypes in the five concentrations of combined cytokinins. The average number of shoots per explant in Super Strain B was found to be the highest (42 and 60 for the hypocotyl and cotyledon explants, respectively). Supplementing MS medium with 1.0 mg L−1 kinetin and 1.0 mg L−1 benzyl adenine was found to be optimum for producing the highest number of shoots per explant from hypocotyls and cotyledons in the tomato genotypes investigated. The proposed medium showed a significant superiority over the reference media.

The three-dimensional arrangement of chromosomes at meiotic metaphase I in normal and interchange heterozygotes of Briza humilis

1990 ◽  
Vol 97 (3) ◽  
pp. 565-570
Author(s):  
JANET M. MOSS ◽  
BRIAN G. MURRAY
Keyword(s):  
Mother Cell ◽  
Three Dimensional ◽  
Meiotic Metaphase ◽  
Central Position ◽  
Normal Plant ◽  
Serial Sections ◽  
Pollen Mother Cells ◽  
Sector Analysis ◽  
Mother Cells ◽  
Metaphase I

Pollen mother cells at metaphase I have been reconstructed from serial sections in normal and interchange heterozygotes of Briza humilis. The pollen mother cells have an irregular shape with a prominent projection from the tangential face into the anther loculus. The seven bivalents of the normal plant are usually arranged with one bivalent in a central position surrounded by a ring of the remaining six or as a ring of all seven bivalents. The central:peripheral distribution of quadrivalents is different in two different interchange plants; in a sector analysis, where cells are divided into four quarters relative to the tangential face of the pollen mother cell, the two plants also show differences in quadrivalent distribution, indicating that individual chromosomes occupy different positions in the cell. The relevance of these results to the positioning of quadrivalents in lateral squashes of meiotic metaphase I are discussed.

scholarly journals Two types of highly ordered micro- and macrochromosome arrangement in metaphase plates of butterflies (Lepidoptera)

2019 ◽  
Vol 13 (1) ◽  
pp. 19-25 ◽  
Author(s):  
Vladimir A. Lukhtanov
Keyword(s):  
Metaphase Plate ◽  
Meiotic Metaphase ◽  
Chromosome Organization ◽  
Cell Divisions ◽  
Size Groups ◽  
Metaphase I

In karyotype of many organisms, chromosomes form two distinct size groups: macrochromosomes and microchromosomes. During cell divisions, the position of the macro- and microchromosomes is often ordered within metaphase plate. In many reptiles, amphibians, birds, insects of the orthopteran family Tettigoniidae and in some plants, a so called “reptilian” type organization is found, with microchromosomes situated in the center of metaphase plate and with macrochromosomes situated at the periphery. An opposite, “lepidopteran” type is known in butterflies and moths (i.e. in the order Lepidoptera) and is characterized by macrochromosomes situated in the center and by microchromosomes situated at the periphery. The anomalous arrangement found in Lepidoptera was previously explained by holocentric organization of their chromosomes. Here I analyse the structure of meiotic metaphase I plates in ithomiine butterfly, Forbestraolivencia (H. Bates, 1862) (Nymphalidae, Danainae, Ithomiini) which has a clear “reptilian” organization, contrary to previous observations in Lepidoptera. In this species large bivalents (i.e. macrochromosomes) form a regular peripheral circle, whereas the minute bivalents (i.e. microchromosomes) occupy the center of this circle. The reasons and possible mechanisms resulting in two drastically different spatial chromosome organization in butterflies are discussed.

scholarly journals Induction and Growth Kinetics Callus of Tomato (Solanum lycopersicum)

2020 ◽  
Vol 12 (1) ◽  
pp. 35-41 ◽  
Author(s):  
Arkan Setiaji ◽  
RR Rifka Annisa ◽  
Rumiyati Rumiyati ◽  
Endang Semiarti
Keyword(s):  
Solanum Lycopersicum ◽  
Growth Kinetics ◽  
Callus Induction ◽  
Dry Weight ◽  
Growth Efficiency ◽  
Ms Medium ◽  
Solanum Lycopersicum L ◽  
Absolute Growth ◽  
Embedded Method

Plant callus extracts are potential to be developed as ingredient in skincare products. Tomato callus is supposed to contain protein-derivatives and or other components such as secondary metabolites that play a role in skin regeneration. Therefore the production of calli is important to be studied for callus sustainable supply. This research aims to obtain optimum medium for callus induction and to analyze tomato callus development anatomically. In vitro culture response was assessed in tomato plant (Solanum lycopersicum L. ‘Permata’) for optimum callus induction. Seeds were grown on ¼ MS medium for 10-15 days. Hypocotyl was excised and cultured on MS medium + 2 mg/l 2,4-D for 15 days as the explants for callus induction. Callus was transferred to MS medium with 8 variations of PGRs including the combination of BAP + NAA, and 2,4-D. Both fresh and dry weight was measured every 5 days over 60 days to establish the growth kinetics and growth efficiency of callus. Anatomic characters of calli were examined through paraffin-embedded method. The result showed of MS medium supplemented with 2.0 mg/l NAA and 0.2 mg/l BAP is optimum for tomato callus induction, based on highest number of the absolute growth rate on fresh weight (73.77% per day), dry weight (3.84% per day), and callus initiation time (5.56 days) achieved by the medium. Cells in the ground tissue of tomato hypocotyl are competent to be dedifferentiated into a callus. This research results were expected to find out suitable methods for tomato callus production in preparation for skincare uses.

Incomplete pole orientation of kinetochores in complex meiotic metaphase I configurations delays metaphase–anaphase transition in Secale

Genome ◽  
2014 ◽  
Vol 57 (4) ◽  
pp. 233-238
Author(s):  
J. Sybenga
Keyword(s):  
Chromosome Segregation ◽  
Secale Cereale ◽  
Anther Development ◽  
Meiotic Metaphase ◽  
Mild Form ◽  
Reciprocal Translocations ◽  
Chromatid Cohesion ◽  
Pole Orientation ◽  
Metaphase I

To prevent unbalanced chromosome segregation, meiotic metaphase I – anaphase I transition is carefully regulated by delaying anaphase until all kinetochores are well oriented (anaphase checkpoint) in mammals and insects. In plants this has not yet been established. In heterozygotes of two reciprocal translocations of Secale cereale, with one chromosome replaced by its two telocentric arms, anaphase delay was correlated with the orientation of the kinetochores of the complex of five chromosomes. The terminal kinetochores of the half chromosomes were readily elongated and pole oriented. Chains of five chromosomes with all five kinetochores orienting on alternate poles where the first to start anaphase. Kinetochores of two adjacent chromosomes when oriented on the same pole were partly shielded and less well pole directed. Anaphase was delayed. Cells with this configuration accumulated during anther development. Kinetochores in metacentric chromosomes lacking chiasmata in one arm (in trivalents and bivalents) were slightly better pole oriented and delayed anaphase less. Release of chromatid cohesion as triggered by kinetochore stretch is apparently delayed by inadequate exposition and pole orientation of the kinetochores. It is a mild form of an anaphase checkpoint, in normal material synchronizing bivalent segregation.

Independent arrangement of bivalents and (or) quadrivalents in linear meiotic metaphase plates of rye

Genome ◽  
1991 ◽  
Vol 34 (3) ◽  
pp. 421-429 ◽  
Author(s):  
P. G. Goicoechea ◽  
A. Roca ◽  
A. R. Linde ◽  
T. Naranjo ◽  
R. Giraldez
Keyword(s):  
Meiotic Metaphase ◽  
Relative Positioning ◽  
C Banding ◽  
Ring Bivalents ◽  
Type 3 ◽  
Metaphase I

The relative positioning of bivalents and (or) quadrivalents in flattened lateral views of metaphase I (linear metaphase plates) has been analyzed in three different plant types of rye: normal plants (type 1); heterozygotes for translocation T305W (type 2); and double heterozygotes for translocations T305W and TR01 (type 3). In all plant types all bivalents and (or) quadrivalents were identified using C-banding. The results indicate that quadrivalents show a preference towards being located in marginal positions of the linear plate, and there are also differences in position preferences between specific bivalents. Adjacently oriented quadrivalents and rod bivalents show a stronger preference for marginal positions than alternate quadrivalents and ring bivalents, respectively, but this does not indicate the existence of a fixed or ordered arrangement of chromosomes in the spindle since bivalents and (or) quadrivalents are independently located relative to each other.Key words: Secale, meiosis, metaphase, arrangement, multivalents, bivalents.

Chromosome organization in meiosis revealed by light microscope analysis of silver-stained cores

Genome ◽  
1987 ◽  
Vol 29 (5) ◽  
pp. 706-712 ◽  
Author(s):  
J. S. Rufas ◽  
J. Gimenez-Abian ◽  
J. A. Suja ◽  
C. Garcia De La Vega
Keyword(s):  
Key Words ◽  
Light Microscope ◽  
Meiotic Chromosome ◽  
Chiasma Formation ◽  
Silver Impregnation ◽  
Meiotic Metaphase ◽  
Chromosome Organization ◽  
Microscope Analysis ◽  
Impregnation Technique ◽  
Metaphase I

Three species of grasshoppers have been analyzed by means of a modified silver impregnation technique that reveals the presence of a chromatid core that identifies chiasmata at first meiotic metaphase. In terms of the behaviour of the chromatid core most of the configurations observed at diplotene with orcein are easily recognized in metaphase I silver-stained bivalents. Some "hidden" configurations, as well as simple chromatin associations, that do not appear to represent chiasmata have also been detected. The disposition and behaviour of the chromatid cores in metaphase I and anaphase I provide grounds to support a reorganization of half-bivalents between first and second division. Key words: chromatid core, meiotic chromosome organization, chiasma formation, insect cytogenetics.

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