Cell-Division of the Pollen-Mother-Cell of Cobaea scandens Alba

1920 ◽  
Vol 47 (8) ◽  
pp. 325 ◽  
Author(s):  
Wanda Kirkbride Farr
Keyword(s):  
Cell Division ◽  
Pollen Mother Cell ◽  
Mother Cell

scholarly journals Meiotic Chromosome Behavior and Capsule Setting in Doritaenopsis Hybrids

2008 ◽  
Vol 133 (1) ◽  
pp. 107-116 ◽  
Author(s):  
Pablo Bolaños-Villegas ◽  
Shih-Wen Chin ◽  
Fure-Chyi Chen
Keyword(s):  
Cell Division ◽  
Pollen Mother Cell ◽  
Chromosome Pairing ◽  
Chromosomal Aberrations ◽  
High Frequency ◽  
Mother Cell ◽  
Seed Set ◽  
Pollen Viability ◽  
High Pollen ◽  
Mother Cells

The development of new cultivars in Doritaenopsis Guillaum. & Lami orchids is often hindered by factors such as low seed count in hybrids. Cytological study may offer the ability to develop new hybrids by revealing cultivars with good chromosome pairing and high pollen viability, which are somewhat difficult to obtain under current breeding programs. Cross pollination, pollen viability, and chromosomal behavior during meiosis were analyzed to reveal the relation between seed fertility and capsule set in Doritaenopsis hybrids. The number of mature capsules harvested and their relative seed content were used as indices of crossing availability. The results of meiosis were evaluated according to pollen viability detected by fluorescein diacetate and quantification of sporad types by acid fuchsin staining. Chromosome number and pairing at meiosis were observed in root tips or in samples of pollen mother cells. A positive relation was found among high seed set, high frequency of viable tetrads, high degree of chromosome pairing, and low frequency of chromosomal aberrations such as inversions and translocations. On the basis of these factors, three types of hybrids could be distinguished. In type one hybrids, chromosomes paired as bivalents, pollen mother cells divided into tetrads, and capsule setting occurred after pollination of pollen acceptors. In type two hybrids, chromosomes remained mainly as univalents that developed into micromeiocytes, pollen mother cell division was disrupted, and seed recovery was low after pollination. Type three hybrids showed chromosomes paired mostly as multivalents, chromosome bridges, pollen mother cell division with massive failure, and little fertility. In Doritaenopsis orchids, high pollen viability and high fertility depends on a high frequency of normal tetrads, and low seed set in cross-pollination is predicted with micronuclei in the end products of meiosis. The occurrence of chromosomal aberrations may suggest a process of genome differentiation that could compromise breeding efforts if not taken into consideration.

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.

scholarly journals Morpho-Histology, Endogenous Hormone Dynamics and Transcriptome Profiling in Dacrydium Pectinatum during Male Cone Development

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1598
Author(s):  
Wenju Lu ◽  
Enbo Wang ◽  
Weijuan Zhou ◽  
Yifan Li ◽  
Zhaoji Li ◽  
...  
Keyword(s):  
Pollen Mother Cell ◽  
Mother Cell ◽  
Cell Formation ◽  
Transcriptome Profiling ◽  
Endogenous Hormone ◽  
Male Cone ◽  
Transcriptome Database ◽  
Cone Development ◽  
Hormone Biosynthesis ◽  
External Forces

Dacrydium pectinatum de Laubenfels is a perennial gymnosperm species dominant in tropical montane rain forests. Due to severe damages by excessive deforestation, typhoons, and other external forces, the population of the species has been significantly reduced. Furthermore, its natural regeneration is poor. To better understand the male cone development in D. pectinatum, we examined the morphological and anatomical changes, analyzed the endogenous hormone dynamics, and profiled gene expression. The morpho-histological observations suggest that the development of D. pectinatum male cone can be largely divided into four stages: microspore primordium formation (April to May), microspore sac and pollen mother cell formation (July to November), pollen mother cell division (January), and pollen grain formation (February). The levels of gibberellins (GA), auxin (IAA), abscisic Acid (ABA), cytokinin (CTK), and jasmonic acid (JA) fluctuated during the process of male cone development. The first transcriptome database for a Dacrydium species was generated, revealing >70,000 unigene sequences. Differential expression analyses revealed several floral and hormone biosynthesis and signal transduction genes that could be critical for male cone development. Our study provides new insights on the cone development in D. pectinatum and the foundation for male cone induction with hormones and studies of factors contributing to the species’ low rate of seed germination.

scholarly journals Sensory mother cell division is specifically affected in a Cyclin-A mutant of Drosophila melanogaster.

1992 ◽  
Vol 11 (8) ◽  
pp. 2935-2939 ◽  
Author(s):  
R. Ueda ◽  
S. Togashi ◽  
M. Takahisa ◽  
S. Tsurumura ◽  
M. Mikuni ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Cell Division ◽  
Mother Cell ◽  
Cyclin A

Changes in Pattern of Microtubule Organization During Meiosis in Pollen Mother Cell of Autotetraploid Rice

2010 ◽  
Vol 36 (10) ◽  
pp. 1777-1785
Author(s):  
Jin-Hua HE ◽  
Xing-An CHENG ◽  
Zhi-Xiong CHEN ◽  
Hai-Bin GUO ◽  
Xiang-Dong LIU ◽  
...  
Keyword(s):  
Pollen Mother Cell ◽  
Mother Cell ◽  
Microtubule Organization ◽  
Autotetraploid Rice

Developmental synchronization of male and female gametophytes inGinkgo bilobaand its neck mother cell division prior to fertilization

2012 ◽  
Vol 147 (4) ◽  
pp. 541-552 ◽  
Author(s):  
Zhongming Zhang ◽  
Sarah C. Clayton ◽  
Keming Cui ◽  
Chenglee Lee
Keyword(s):  
Cell Division ◽  
Mother Cell ◽  
Male And Female

Relationships between inbreeding, meiotic irregularity, and fertility in alfalfa

1986 ◽  
Vol 28 (1) ◽  
pp. 130-137 ◽  
Author(s):  
S. E. Smith ◽  
R. P. Murphy
Keyword(s):  
Medicago Sativa ◽  
Seed Production ◽  
Inbreeding Depression ◽  
Pollen Mother Cell ◽  
Mother Cell ◽  
Pollen Parent ◽  
Meiotic Behavior ◽  
Negatively Associated ◽  
Meiotic Irregularity ◽  
Medicago Sativa L

Fertility (seed production) in alfalfa (Medicago sativa L.) is severely depressed by inbreeding; however, little is known of the factors directly responsible for this depression. Irregularities in meiotic behavior could be partially responsible for the inbreeding depression in fertility observed. This study considered relationships between fertility, inbreeding, and irregularity in microsporogenesis. Fertility declined markedly with inbreeding in the materials examined (S0–S3). Irregularity in microsporogenesis, as measured by the percent irregular quartets, (i.e., quartets with micronuclei, supernumerary microspores, or irregular cytokinesis) increased significantly with inbreeding. Increases in quartet irregularity were associated with increases in the number of univalents per pollen mother cell observed at metaphase I. Considering all materials studied, the percentage of irregular quartets was negatively and significantly correlated with fertility as both a seed and a pollen parent. In more detailed analyses, it was observed that the percent irregular quartets was negatively associated with fertility as a pollen parent only when levels of irregularity were relatively high. No association was observed between the percent irregular quartets and fertility when levels of irregularity were relatively low.Key words: Medicago, microsporogenesis, seed production, breeding, fertility.

Sign in / Sign up

Export Citation Format

Share Document