MITOTIC CYCLES IN ROOT TIP CELLS OF TWO SPECIES OF TRILLIUM (LILIACEAE)

1970 ◽  
Vol 12 (4) ◽  
pp. 750-758 ◽  
Author(s):  
E. R. Boothroyd ◽  
Nancy MacDonald Mark
Keyword(s):  
Mitotic Cycle ◽  
The Other ◽  
Root Tip ◽  
Cycle Times ◽  
Autoradiographic Technique ◽  
Tip Cells ◽  
Root Tip Cells

There is a fourfold difference in the reported lengths of the mitotic cycles in Trillium. One report (29 hours at 23 °C for T. erectum) was based on the colchicine tag method, whereas the other (120 hours at 25 °C for T. grandiflorum) was based on the autoradiographic technique. In the present study both methods were used on both species. Experiments, carried out at 20 °C, gave minimum estimates of 104 hours and 84 hours respectively for T. grandiflorum and T. erectum, as determined by the colchicine method, and 92 hours and 80 hours by autoradiography. Both methods gave evidence of the existence of two or more populations of cells with different mitotic cycle times.

DISTRIBUTION OF HETEROCHROMATIN IN THE CHROMOSOMES OF HAPLOPAPPUS GRACILIS

1968 ◽  
Vol 10 (2) ◽  
pp. 433-443 ◽  
Author(s):  
Ira H. Ames ◽  
Jyotirmay Mitra
Keyword(s):  
Aqueous Solution ◽  
Chromosome Aberrations ◽  
Maleic Hydrazide ◽  
Cold Treatment ◽  
The Other ◽  
Root Tip ◽  
Metaphase Chromosomes ◽  
Haplopappus Gracilis ◽  
Tip Cells ◽  
Root Tip Cells

Several approaches were employed to study the distribution of heterochromatin in root tip chromosomes of Haplopappus gracilis. Cold treatment and pretreatment in an aqueous solution of 8-hydroxyquinoline revealed achromatic gaps in metaphase chromosomes. Cold treatment also permitted the demonstration of positive heteropycnosis in prophase chromosomes. Further support for the identification of heterochromatic segments was provided by a study of the localization of chromosome aberrations induced by maleic hydrazide and an analysis of the pattern of DNA synthesis in chromosomes of root tip cells. Seven of the ten regions that were preferentially broken by maleic hydrazide also reacted differentially to cold treatment or to pretreatment with 8-hydroxyquinoline. A good correlation was found between regions that completed DNA replication late in the DNA-synnhetic period and segments that were shown to be heterochromatic by the other techniques.

Effect of sodium fluoride treatments on the mitotic cycle of root-tip cells in jack pine seedlings

1989 ◽  
Vol 67 (5) ◽  
pp. 1606-1608 ◽  
Author(s):  
J. J. Zwiazek ◽  
Jennifer M. Shay
Keyword(s):  
Sodium Fluoride ◽  
Pinus Banksiana ◽  
Mitotic Cycle ◽  
Jack Pine ◽  
Root Tip ◽  
Pine Seedlings ◽  
Induced Changes ◽  
Tip Cells ◽  
Accumulation Method ◽  
Root Tip Cells

Fluoride-induced changes in the mitotic cycle were studied in root-tip cells of jack pine (Pinus banksiana Lamb.) seedlings using the metaphase accumulation method. Sodium fluoride treatments resulted in lengthening of the mitotic cycle. This was due to an increase in the duration of interphase. The duration of mitosis and individual mitotic phases was not affected by the treatments.

Sunlight decreased genotoxicity of azadirachtin on root tip cells of Allium cepa and Eucrosia bicolor

2010 ◽  
Vol 73 (5) ◽  
pp. 949-954 ◽  
Author(s):  
W. Kwankua ◽  
S. Sengsai ◽  
C. Kuleung ◽  
N. Euawong
Keyword(s):  
Allium Cepa ◽  
Root Tip ◽  
Tip Cells ◽  
Root Tip Cells

Salt Stress-induced Programmed Cell Death in Rice Root Tip Cells

2007 ◽  
Vol 49 (4) ◽  
pp. 481-486 ◽  
Author(s):  
Jian-You Li ◽  
Ai-Liang Jiang ◽  
Wei Zhang
Keyword(s):  
Cell Death ◽  
Salt Stress ◽  
Programmed Cell Death ◽  
Rice Root ◽  
Root Tip ◽  
Tip Cells ◽  
Root Tip Cells

Cytological evidence bearing on the origin of the B genome in polyploid wheats

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 36-43 ◽  
Author(s):  
K. Kerby ◽  
J. Kuspira
Keyword(s):  
Dna Hybridization ◽  
Triticum Turgidum ◽  
Root Tip ◽  
Cytological Evidence ◽  
B Genome ◽  
Genome Donor ◽  
The One ◽  
Genome Donors ◽  
Tip Cells ◽  
Root Tip Cells

To help elucidate the origin of the B genome in polyploid wheats, karyotypes of Triticum turgidum, Triticum monoccum, and all six purported B genome donors were compared. The analysis utilized a common cytological procedure that employed the most advanced equipment for the measurement of chromosome lengths at metaphase in root tip cells. A comparison of the karyotypes of T. turgidum and T. monococcum permitted the identification of B genome chromosomes of T. turgidum. These consist of two SAT pairs, one ST pair, three SM pairs, and one M pair of homologues. Comparisons of the chromosomes of the B genome of T. turgidum with the karyotypes of the six putative B genome donors showed that only the karyotype of Aegilops searsii was similar to the one deduced for the donor of the B genome in T. turgidum, suggesting that Ae. searsii is, therefore, the most likely donor of the B genome to the polyploid wheats. Support for this conclusion has been derived from geographic, DNA-hybridization, karyotype, morphological, and protein data reported since 1977. Reasons why the B genome donor has not been unequivocally identified are discussed.Key words: phylogeny, karyotypes, Triticum turgidum, Triticum monococcum, B genome, B genome donors.

scholarly journals Squash Preparations of Living Root-Tip Cells

Nature ◽  
1949 ◽  
Vol 164 (4178) ◽  
pp. 930-930 ◽  
Author(s):  
J. CHAYEN
Keyword(s):  
Root Tip ◽  
Living Root ◽  
Tip Cells ◽  
Root Tip Cells
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