Endosperm mitotic activity and endoreduplication in maize affected by defective kernel mutations

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 68-77 ◽  
Author(s):  
R. V. Kowles ◽  
M. D. McMullen ◽  
G. Yerk ◽  
R. L. Phillips ◽  
S. Kraemer ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Dna Content ◽  
Endosperm Development ◽  
Kernel Weight ◽  
Endosperm Nucleus ◽  
Endosperm Cell ◽  
Cell Numbers

A group of 35 defective kernel (dek) mutants in maize has been studied with regard to their effect on endosperm development. Information is reported on kernel weight, kernel viability, mutant transmission, DNA content per endosperm nucleus, endosperm cell numbers during development, and DNA endoreduplication patterns. All of the dek mutations reduced mitotic activity and resulted in greatly reduced cell numbers. All except one mutation decreased DNA endoreduplication. The exception indicates that the processes of mitotic activity and endoreduplication can be uncoupled. Notable differences in DNA endoreduplication patterns were observed among the dek strains. Defective kernels with homozygous defective embryos did not germinate in any of these strains, although some morphologically defective kernels did germinate and were shown to have normal embryos of +/+ or +/dek genotype. Dek mutants that had a defective endosperm and an embryo that developed normally were not identified. The mutations investigated are recessive, but F2 segregation for many of the mutants revealed significant deviations from expected 3:1 ratios.Key words: defective kernels, endosperm, endoreduplication.

scholarly journals Mitotic activity and changes in DNA content during Zea mays L. endosperm development

2014 ◽  
Vol 71 (3) ◽  
pp. 195-200
Author(s):  
Hanna Kuran ◽  
Kazimierz Marciniak
Keyword(s):  
Zea Mays ◽  
Mitotic Activity ◽  
Dna Content ◽  
Nuclear Dna ◽  
Zea Mays L ◽  
Nuclear Dna Content ◽  
Staining Intensity ◽  
Endosperm Development ◽  
Dna Contents ◽  
Mitotic Figures

Mitotic activity and nuclear DNA content in endosperm of <em>Zea mays</em> cv. Złota Karłowa were examined. DNA content was cytophotometrically measured on squashed preparations after Feulgen procedure. Mitotic activity in endosperm was determined till the stage when embryo sack reached 4.5 mm in length. Some of mitotic figures show multiplied DNA content. Endosperm nuclei have various DNA contents which increase throughout endosperm development. DNA content enhancement indicates endoreduplication in progress. Some nuclei with high DNA content display changes in chromatin structure, which are expressed by the presence of strands and aggregates of chromatin characterised by high staining intensity. A conclusion has been drawn that mitotic divisions and the endoreduplication phase of nuclear DNA may occur simultaneously and dominate one over another at different phases of endosperm development.

Changes in chromosome structure, mitotic activity and nuclear DNA content from cells of Allium Test induced by bark water extract of Uncaria tomentosa (Willd.) DC

2006 ◽  
Vol 107 (2) ◽  
pp. 211-221 ◽  
Author(s):  
Mieczysław Kuraś ◽  
Julita Nowakowska ◽  
Elwira Śliwińska ◽  
Radosław Pilarski ◽  
Renata Ilasz ◽  
...  
Keyword(s):  
Mitotic Activity ◽  
Dna Content ◽  
Nuclear Dna ◽  
Chromosome Structure ◽  
Water Extract ◽  
Nuclear Dna Content ◽  
Allium Test ◽  
Uncaria Tomentosa

scholarly journals DNA CONTENT OF PLACENTAL NUCLEI

1962 ◽  
Vol 13 (2) ◽  
pp. 183-191 ◽  
Author(s):  
Michael Galton
Keyword(s):  
Cell Proliferation ◽  
Dna Synthesis ◽  
Mitotic Activity ◽  
Dna Content ◽  
Reproductive Capacity ◽  
Interphase Nuclei ◽  
Daughter Cells ◽  
Reproductive Ability ◽  
Dna Values ◽  
Rapid Accumulation

The DNA content of individual nuclei in four immature human placentas was determined by microspectrophotometric analysis of Feulgen-stained sections. The absence of mitosis in the syncytiotrophoblast, taken together with the finding of a diploid unimodal distribution, at a time of rapid placental growth, indicated that the syncytiotrophoblast possessed little or no intrinsic reproductive capacity. In contrast, the cytotrophoblast displayed considerable mitotic activity and was found to contain a high proportion of nuclei with DNA values in excess of the diploid amount, corresponding to DNA synthesis in interphase nuclei preparatory to division. From the complementary behavior of the two layers of trophoblast, with respect to evidence of reproductive ability, it is concluded that the rapid accumulation of nuclei in the syncytiotrophoblast, during the early development of the placenta, is accounted for by cell proliferation within the cytotrophoblast followed by alignment and coalescence of some daughter cells in the syncytiotrophoblast.

Early seed development in the annual and perennial Secale taxa

1985 ◽  
Vol 27 (2) ◽  
pp. 134-142 ◽  
Author(s):  
J. P. Gustafson ◽  
A. J. Lukaszewski
Keyword(s):  
Seed Development ◽  
Dna Content ◽  
Endosperm Development ◽  
Early Embryo ◽  
Embryo Cell ◽  
Developmental Patterns ◽  
Positive Correlation ◽  
Embryo Cells ◽  
Telomeric Heterochromatin ◽  
Early Seed Development

The early embryo and endosperm development patterns of five annual taxa and three perennial taxa of the genus Secale were analyzed. The results showed that there was considerable variation in the speed of early embryo and endosperm development within the genus Secale, and that the developmental patterns of the annual and perennial taxa overlapped. Comparisons indicated that DNA content per se did not have any influence on the speed of early embryo development or aberrant endosperm nucleus production in either the annual or perennial taxa. However, comparisons between the percent telomeric heterochromatin and the number of embryo cells produced showed a significant positive correlation in the annual taxa, and a nonsignificant correlation in the perennial taxa. There was a positive correlation between the number of aberrant endosperm nuclei and percent telomeric heterochromatin in the annual taxa, while the perennial taxa showed a nonsignificant but negative correlation. The results suggest that percent telomeric heterochromatin has a different effect on early seed development in the annual taxa than in the perennial taxa.Key words: Secale, heterochromatin, DNA content, embryo cell cycle.

Cellular endosperm formation in Phaseolus vulgaris. I. Light and scanning electron microscopy

1988 ◽  
Vol 66 (6) ◽  
pp. 1209-1216 ◽  
Author(s):  
Edward C. Yeung ◽  
Michael J. Cavey
Keyword(s):  
Phaseolus Vulgaris ◽  
Mitotic Activity ◽  
Endosperm Development ◽  
Bean Seed ◽  
Phaseolus Vulgaris L ◽  
Entire Surface ◽  
Cotyledon Stage ◽  
Cellular Endosperm ◽  
Inner Surface ◽  
Endosperm Formation

The formation of the endosperm in Phaseolus vulgaris L. conforms to the nuclear pattern of endosperm development. The endosperm is partially cellularized in the vicinity of the developing embryo, while the rest of the endosperm remains multinucleate. Mitotic activity of the endosperm is gradually confined to the region adjacent to the tips of the enlarging cotyledons. Continuing mitotic activity in this region results in the formation of cellular endosperm in the bean seed. At the cotyledon stage of embryo development, except in the region of the degenerating nucellus, the entire surface of the developing embryo is covered by a layer of cellular endosperm cells. Initially, the cellular endosperm is loosely attached to the inner surface of the seed coat. With the disappearance of the liquid endosperm, it becomes firmly attached. Further expansion of the seed results in the separation of cellular endosperm cells along their long axes. As the seed matures, the cellular endosperm dries, with no apparent degradation of its cells.

A study of DNA and mitotic activity in the vegetative apex of Douglas fir during the annual growth cycle

1973 ◽  
Vol 51 (7) ◽  
pp. 1395-1409 ◽  
Author(s):  
John N. Owens ◽  
Marje Molder
Keyword(s):  
Mitotic Activity ◽  
Dna Content ◽  
Peripheral Zone ◽  
Growth Cycle ◽  
Nuclear Volume ◽  
Annual Growth ◽  
Axillary Shoots ◽  
Volume Percentage ◽  
Leaf Initiation ◽  
Mother Cells

Vegetative apices of Pseudotsuga menziesii (Mirb.) Franco were studied throughout the annual growth cycle. When observations based on anatomy, histochemistry, and external morphology are combined, the growth cycle of the vegetative apex should be subdivided into five stages: (1) dormancy, (2) early bud-scale initiation, (3) late bud-scale initiation and rapid apical enlargement, (4) early, rapid leaf initiation, and (5) late, slow leaf initiation. The same cytohistological zonation pattern is present in vegetative apices throughout the growth cycle and usually consists of apical, peripheral, and rib meristem zones. During dormancy, early bud-scale initiation, and early leaf initiation, the apical zone is separated into apical initials and central mother cells based on nuclear characteristics and mitotic activity. Cytohistological zonation is supported by constant differences in nuclear volume, mitotic activity, and DNA content between zones. The peripheral zone is mitotically more active than the apical zone; however, the apical zone is not quiescent. Zones vary in size, prominence, and mitotic activity, which often relates to a particular developmental stage of the apex. The dormant apex has no mitotic activity, and cytohistological zonation is present but not distinct. Zonation increases throughout the first half of the growing season, reaches a maximum during late bud-scale and early leaf initiation, and decreases as dormancy approaches. In general, increases in nuclear volume, percentage of nuclei at 4C, and average DNA content per nucleus correlate with increases in the prominence of zonation. Zonation did not result from different zones being "held" at certain C levels of DNA. Although nuclear volume was used in calculating the DNA content, the DNA level often varied independently of volume. Mitotic activity and dormancy appear to be related to carbohydrate levels within the bud and subtending shoot. The period of most prominent zonation is also the period of most active primordial initiation, largest apical size, and the time when new axillary shoots become determined in their pathway of development.

Evénements structuraux et métaboliques dans les entre-nœuds des bourgeons axillaires du pois, en réponse à la levée de dominance

1978 ◽  
Vol 56 (10) ◽  
pp. 1213-1228 ◽  
Author(s):  
Arlette Nougarède ◽  
Pierre Rondet
Keyword(s):  
Cell Growth ◽  
Pisum Sativum ◽  
Mitotic Activity ◽  
Dna Content ◽  
Apical Dominance ◽  
Mitotic Cycle ◽  
Homogeneous Reaction ◽  
Basal Portion ◽  
Elongation Phase ◽  
Synthetic Phase

Events associated with the release from dominance are described for internodes 1 and 2 of the axillary buds of Pisum sativum. During the inhibited state, most of the nuclei are found in the G1 phase of a diploid cycle. At the release from dominance, some nuclei in the G2 phase during inhibition enter into mitosis and the nuclei in G1 enter into the DNA synthetic phase. Until the 3rd day, a homogeneous reaction is registered for the whole of the two first internodes. Three maxima of mitotic activity are detected in the epidermis, the cortex, and the procambium and only one in the pith. From the 3rd day, the mitoses are localized at the uppermost part of these internodes: meanwhile, elongation occurs in their basal portion. At this level, the nuclear volumes are maximal at the 6th day. After release from apical dominance, the increase in DNA content reflects the resumption of the mitotic cycle and, subsequently, the onset of differentiation, with 4C level nuclei in the cortex and 8C nuclei in the pith. The cell growth of the epidermis, the cortex, and the pith, either radial or tangential, precedes the elongation phase.

ROLE OF VASOPRESSIN IN THE MITOTIC RESPONSE OF RAT BONE MARROW CELLS TO HAEMORRHAGE

1977 ◽  
Vol 72 (1) ◽  
pp. 5-16 ◽  
Author(s):  
N. H. HUNT ◽  
A. D. PERRIS ◽  
P. A. SANDFORD
Keyword(s):  
Bone Marrow ◽  
Mitotic Activity ◽  
Bone Marrow Cells ◽  
Cell Numbers ◽  
Severe Haemorrhage ◽  
Mitogenic Action ◽  
Stimulate Bone Marrow

SUMMARY Two days after a severe haemorrhage plasma calcium concentrations and bone marrow mitotic activity in rats were significantly increased and so remained for a further 5–6 days until the haematocrit had returned to normal. The first 48 h after bleeding were characterized by hypocalcaemia. During this phase two significant peaks in mitotic activity were observed at 4 and 18 h after haemorrhage. The mitotic surge 4 h after bleeding was still present in adrenalectomized and parathyroidectomized animals but in rats which were either hypophysectomized or had congenital diabetes insipidus this mitotic response was absent. Vasopressin was shown to stimulate bone marrow mitotic activity both in vivo and in vitro whereas angiotensin, aldosterone and erythropoietin had no rapid, direct mitogenic action on these cells. This novel hypophysial–bone marrow system suggests that vasopressin may assist in post-haemorrhagic recovery in blood cell numbers in the circulation.

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