scholarly journals The Mitoses in the Spore Mother-Cell of Pallavicinia

1903 ◽  
Vol 36 (5) ◽  
pp. 384-388 ◽  
Author(s):  
Andrew C. Moore
Keyword(s):  
Mother Cell ◽  
Spore Mother Cell

scholarly journals Changes in the nuclear structure of bacteria, particularly during spore formation

1945 ◽  
Vol 44 (2) ◽  
pp. 99-108 ◽  
Author(s):  
Emmy Klieneberger-Nobel
Keyword(s):  
Nuclear Structure ◽  
Mother Cell ◽  
Spore Formation ◽  
Developmental Cycle ◽  
Spore Mother Cell ◽  
Nuclear Changes ◽  
Fusion Cell ◽  
Ripe Spore ◽  
The Individual ◽  
Stage 1

Changes of nuclear structure in bacteria have been studied by means of the hydrochloric acid-Giemsa method which produces brilliantly stained specimens and can be carried out with almost the same ease as some of the ordinary routine staining techniques.The nuclear changes in the four spore-bearing organisms studied are outlined in Text-fig. III, to which the following numbers refer. The dumbbell bodies which are dispersed in the cells of the young growth (1) become alined in the long axis of the cell (2) where they eventually fuse into an axial nuclear cylinder (3, 4). These cells divide up into fusion cells of approximately the same length (5). The development of the ‘chromosome’ stage (1) into the fusion cell (5) is the first step in the process of sporulation. During its further development the fusion cell or spore mother cell divides twice (6, 7), with the result that it is segregated into four structures which often assume dumbbell shape. Therefore the chromatin cylinder of the individual spore mother cell seems to be equivalent to four nuclear elements one of which functions as the spore ‘chromosome’ (‘nucleus’?), whereas the remaining three disintegrate (8, 9). The ripe spore (9) representing, as it does, the smallest cell unit contains one nuclear structure only.Therefore the two main features in spore formation of bacteria appear to be (1) a fusion of the dumbbell bodies into an axial chromatin rod (‘autogamy’?), (2) a reduction partition which is reminiscent of, though not corresponding to, the more complicated phenomenon of meiosis in the higher organisms. The sporulation, as outlined in this paper, gives new proof of the important part played by the chromatinic dumbbell bodies (‘chromosomes’) in the developmental cycle of spore-bearing organisms. The fusion cell with its axial chromatin cylinder has for the first time been proved to have a progressive functional significance as a stage in a nuclear cycle. The particular mode of fusion followed by reduction partition suggests that the chromatinic dumbbell bodies may be concerned with the transmission of the hereditary characters in bacteria.

The Spore-Mother-Cell of Anthoceros

1899 ◽  
Vol 28 (2) ◽  
pp. 89-109 ◽  
Author(s):  
Bradley Moore Davis
Keyword(s):  
Mother Cell ◽  
Spore Mother Cell

Whi3 Mnemon Association with Endoplasmic Reticulum Membranes Confines the Memory of Deceptive Courtship to the Yeast Mother Cell

2020 ◽  
Author(s):  
Yasmin Lau ◽  
Marcel Grogg ◽  
Iuliia Parfenova ◽  
Juha Saarikangas ◽  
Richard Alan Nichols ◽  
...  
Keyword(s):  
Endoplasmic Reticulum ◽  
Mother Cell

Cell grouping and primary wall generations in the cambial zone, xylem, and phloem in Pinus

1968 ◽  
Vol 16 (2) ◽  
pp. 177 ◽  
Author(s):  
A Mahmood
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Secondary Wall ◽  
Radial Direction ◽  
Cell Plate ◽  
Tangential Direction ◽  
Primary Wall ◽  
Photographic Evidence ◽  
Secondary Wall Deposition ◽  
Cambial Zone

The use of the term cambium, or equivalent terms, in modern literature is discussed. The term cambial zone adopted in this paper includes the cambial initial and the dividing and enlarging cells. The tissue mother cell produced at each division of the initial produces a group of four cells in xylem or two cells in phloem. Theoretical constructs have been made for xylem and phloem production by associating the concepts that xylem and phloem are produced in alternate series of initial divisions and that a new primary wall is deposited around each daughter protoplast at each cell division. Correlations are derived from the theoretical constructs for the thickness of primary wall layers lying in the tangential direction and of those lying in the radial direction at progressive histological levels. Deductions from theoretical constructs are made when the initial is producing xylem, when it changes its polarity from xylem to phloem production, and when the reverse change occurs. Most of the theoretical deductions are supported by photographic evidence. The chief point of this study is the demonstration of generations (multiplicity) of primary parental walls. The term intercellular material proposed in this paper includes the cell plate plus any remnants of ancestral primary walls between the current primary walls surrounding the adjacent protoplasts. This term is still applicable to cells where secondary wall deposition is taking place or has been completed.

Embryological studies in the compositae, I. Sporogenesis, Gametogenesis, and Embryogeny in Cotula australis (Less.) Hook. F

1962 ◽  
Vol 10 (1) ◽  
pp. 1 ◽  
Author(s):  
GL Davis
Keyword(s):  
Mother Cell ◽  
Megaspore Mother Cell ◽  
Embryo Sac ◽  
Subsequent Development ◽  
Pollen Grains ◽  
Archesporial Cell ◽  
Polygonum Type ◽  
Wall Formation ◽  
Chalazal Megaspore

Cotula australis has a discoid heterogamous capitulum in which the outermost three whorls of florets are female and naked. The bisexual disk florets are fully fertile and have a four-lobed corolla with four shortly epipetalous stamens. The anthers contain only two microsporangia. Wall formation and microsporogenesis are described and the pollen grains are shed at the three-celled condition. The ovule is teguinucellate and the hypodermal archesporial cell develops directly as the megaspore mother cell. Megasporogenesis is normal and the monosporio embryo sac develops from the chalazal megaspore. Breakdown of the nucellar epidermis takes place when the embryo sac is binucleate and its subsequent development follows the Polygonum type. The synergids extend deeply into the micropyle and one persists until late in embryogeny as a haustorium. The development of the embryo is of the Asterad type, and the endosperm is cellular. C. coronopifolia agrees with C. australis in the presence of only two microsporangia in each anther and the development of a synergid haustorium.

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