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  • 1
    Digitale Medien
    Digitale Medien
    Changes in Mitotic Index Induced By Colchicine (1966)
    [s.l.] : Nature Publishing Group
    Nature 212 (1966), S. 1541-1542 
    Details
    ISSN: 1476-4687
    Quelle: Nature Archives 1869 - 2009
    Thema: Biologie , Chemie und Pharmazie , Medizin , Allgemeine Naturwissenschaft , Physik
    Notizen: [Auszug] THK mitotie index, the percentage of cells in division, is known to increase in actively dividing cell populations which have been treated with colchicine. This increase, which has been frequently described1, is detected in the first few hours of treatment and is caused by the accumulation of cells ...
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1038/2121541a0
    Standort Signatur Erwartet Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    Changes in mitotic indices in roots of Vicia faba (1966)
    Springer
    Chromosoma 18 (1966), S. 421-437 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Roots of Vicia faba were treated with solutions of colchicine or IAA or both. Mitotic indices and the frequencies of the different stages of mitosis were determined immediately after a three hour treatment or following a 24 hour period of recovery. Roots scored after treatment with colchicine for three hours showed several effects, none of which were reversed by simultaneous treatment with IAA. Treatment with IAA for three hours had little detectable effect on mitotic index (MI) on the frequencies of the various stages of mitosis. After a recovery period, following a three hour treatment, of 24 hours, colchicine treated roots showed a significant increase in their MI; this was due largely to an increase in the number of metaphases but it was also due in part to the presence of tetraploid cells in division. IAA treated roots revealed an inhibition of mitotic activity, which was most marked at 3.13–6.26×10−4 M IAA. The results from roots treated with mixtures of colchicine and IAA for three hours and fixed 24 hours later showed: 1) the increase in MI induced by colchicine is reversed by IAA, the intensity of the reversal increasing with increasing concentrations of IAA; 2) reductions in the total numbers of cells in prophase or in metaphase occur after treatment with different concentrations of IAA; 3) IAA leads to a reduction in the number of tetraploid cells seen in division. It appears that colchicine induces a change in the pattern of mitotic activity 24 hours after the end of treatment and its effects are reversed by IAA. At 4.2×10−4 M IAA a balance occurs between the opposing effects of colchicine and IAA and the MI is not significantly different from that of the controls. It is suggested that one result of a treatment with colchicine is a change in the level of growth factors in root meristems. This change, which appears to result in a temporary increase in MI is reversed by the addition of IAA. Thus one of the growth factors, the level of which has been affected, is replaceable by exogenous IAA.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00332546
    Standort Signatur Erwartet Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Changes in the mitotic cycle in lateral root meristems of Vicia faba following kinetin treatment (1968)
    Springer
    Chromosoma 24 (1968), S. 177-187 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Roots of Vicia faba were treated with H3-Thymidine (1 μC/ml) for one hour, either before or after a three hour treatment with a 10−5 M solution of kinetin. The durations of the mitotic cycle and its constituent phases were then derived from the curves recording the rhythmic entry and exit of labeled cells in prophase, both for the kinetin treated roots and the controls. The rate of DNA synthesis was also determined for the control roots and for roots exposed to H3-Thymidine immediately following treatment with kinetin. — Control values for the durations of the mitotic cycle, G1, S, G2 and mitosis were in agreement with most of the results reported in the literature. Kinetin treatment resulted in an increase in the rate of DNA synthesis, but did not affect the number of cells undergoing DNA synthesis, i.e. kinetin, or a similar compound, may be involved in the control of the rate of DNA synthesis in plant root meristems, but it does not appear to be involved in the control of the initiation of the S period of interphase. — The durations of G1 and G2 are shorter and longer respectively in the kinetin treated roots as compared with the control values. Changes in the durations of these phases of interphase, S, cycle time and the rate of cell proliferation have been discussed with respect to time after kinetin treatment and their possible relationship to carbohydrate metabolism.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00285200
    Standort Signatur Erwartet Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Lateral root formation in Vicia faba L. (1972)
    Springer
    Chromosoma 39 (1972), S. 341-350 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract MI was found to decrease in LP with increase in cell number, and reached minimal values just before the emergence of LP to form lateral roots. These changes in MI have been correlated with the accumulation of cells in G1, 24 hours before a lateral root is formed. The durations of C and the various phases of the mitotic cycle were also investigated in LP, and compared with those in small primordia. As lateral root primordia increase in cell number, the durations of C, S and G2 become longer, while G1 becomes shorter. Also MI and GF decrease while the proportion of quiescent cells increases. Thus, there is a gradual decrease in the rate of cell proliferation as primordia increase in size. The changes which take place in these parameters during lateral root primordium development have been compared with the events which occur in seed proliferating tissues at the onset of dormancy.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00290792
    Standort Signatur Erwartet Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    Heterogeneity in Cell Behaviour in Primordia ofVicia faba (1968)
    Springer
    Chromosoma 25 (1968), S. 470-474 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The response of cells of small primordia ofVicia faba to3H-TdR and colchicine is discussed. The delayed uptake of3H-TdR shown by cells of small primordia appears to be a property of only 50% of the cells; the remaining never become capable of incorporating3H-TdR. Prom the labeled cells and polyploid cells induced by colchicine the shortest cycle time in small primordia is estimated to be 12 hours. Within a period equal to 1 mitotic cycle, 31–35% of all mitoses are tetraploid, following treatment with colchicine. The remainder are diploid and diploid mitoses were seen for up to 30 hours. These observations are indicative of a heterogeneity for mitotic cycle time in populations consisting of up to 1,500 cells. The percentage labeled mitosis curve of diploid cells was changed in primordia treated with colchicine; higher peaks were found. These results show that even small populations of cells, at the beginning of a morphogenetic system, are very heterogeneous for key cell properties.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF02327723
    Standort Signatur Erwartet Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    Some effects of 2,4,5-trichlorophenoxyacetic acid on the mitotic cycle of lateral root apical meristems of Vicia faba (1969)
    Springer
    Chromosoma 27 (1969), S. 327-337 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Roots of Vicia faba were given a one hour pulse label with. 3H-TdR (1 μC/ml), either before or after a three hour treatment with a 10−5 M solution of 2,4,5-trichlorophenoxyacetic acid (TCPA). The durations of the various phases of the mitotic cycle were derived from labeled prophase curves, prepared from autoradiographs of lateral root apical meristems. — TCPA was found to lengthen the duration of the mitotic cycle, primarily because it extended the duration of the period of DNA synthesis (S), though post-synthetic interphase (G2) was also longer. No measurements could be made with respect to the duration of presynthetic interphase (G1), because of rapid changes in the lengths of the G2 and S periods following treatment. — As well as extending the duration of S, TCPA treatment also resulted in at least an initial increase in the rate of DNA synthesis and a decrease in the actual number of cells in S. These results have been discussed with respect to the control of the organization of the root apical meristem.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00326169
    Standort Signatur Erwartet Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    The response of apical meristems of primary roots of Vicia faba L. to colchicine treatments (1971)
    Springer
    Chromosoma 35 (1971), S. 217-232 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract The effects of 0.5% and 0.025% solutions of colchicine on the passage of cells through the mitotic cycle in apical meristems of primary roots of Vicia faba have been examined. Both treatments affected cell progression through the mitotic cycle in the same way: S and G1 were shorter, and G2 and mitosis longer, than the corresponding control values. The duration of the various phases of the mitotic cycle were similar to those reported previously for apical meristems of lateral roots though cycle time itself was longer. Recovery of root proliferating tissues from colchicine-induced inhibition of growth is correlated with the presence of quiescent cells. Meristems which have no quiescent cells do not recover from eolchicine treatment, while meristems which contain many quiescent cells recover faster than those which contain few. The growth fraction and the proportion of proliferating cells with a short cycle time are linearly related to the duration of the S period in root meristems.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00285738
    Standort Signatur Erwartet Verfügbarkeit
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  • 8
    Digitale Medien
    Digitale Medien
    Studies on induced changes in growth patterns and polarity in roots of Vicia faba L. (1966)
    Springer
    Planta 71 (1966), S. 257-267 
    Details
    ISSN: 1432-2048
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Roots of Vicia faba were treated with colchicine (0.025%), or IAA (4.7×10-6 M), or both, for 3 hours and fixed at various intervals over the following 11 days. The axis of spindle orientation and the distribution of mitotic figures, lateral root primordia and xylem vessel elements was examined in the apical 10 mm of median longitudinal sections of these roots. No effect of IAA was found on the orientation of the spindle. However, evidence was obtained indicating that the systems controlling the polarity of cell division and cell expansion differ in some way. The number of lateral root primordia formed was greater in roots treated with IAA or colchicine than in control roots. These primordia were always initiated adjacent to a xylem vessel. Thus, no primordium was closer to the apex than the most apical xylem vessel, suggesting that an endogenous factor involved in primordia initiation is transported in the xylem. The primordia which develop after colchicine treatment grow out as lateral roots; this is in contrast with those which form after IAA treatment and which do not undergo elongation. These results, which it must be emphasized apply only to the apical 1 cm of treated roots, indicate that lateral root primordia become sensitive to IAA at a certain stage in their development. Exogenous IAA acts as an inhibitor. The new meristem, which forms in the primary root apex after colchicine treatment, contains both diploid and polyploid cells, i.e. it was formed from cells that were unaffected and from cells that were affected by colchicine. Following colchicine treatment the size of the meristem shrinks and this can be prevented by treatment with IAA. This and other evidence presented here, suggests that IAA is a factor involved in the control of the size of the apical meristem in normal roots.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00384887
    Standort Signatur Erwartet Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Delayed incorporation of H3-thymidine by primordial cells (1968)
    Springer
    Chromosoma 24 (1968), S. 1-9 
    Details
    ISSN: 1432-0886
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Roots of Vicia faba were treated with H3-thymidine (1 μc/ml) for 1 h and incorporation of H3-TdR into nuclei of primordia was studied. Large primordia (〉1,500 cells) did not incorporate H3-TdR. Cells of small primordia did not incorporate the labeled precursor immediately but did so after a delay of several hours. The frequency of labeled nuclei became similar to that of lateral meristems only after a delay of 12–14 h. The gradual increase in labeling index also occurs in colchicine treated cells, which do not divide; this shows that the rise in labeling index is not due solely to the division of labeled cells. It has been estimated from H3-TdR and colchicine labeled cells that small primordia have a population of cells in which intermitotic time is about 12 h. The delay in incorporation appears to indicate that pools of H3-TdR can be maintained in small primordia for several hrs and that the precursor is not used until the cells synthesize thymidine kinase.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00329602
    Standort Signatur Erwartet Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Colchicine induced changes in the rate of entry of cells into prophase in roots ofVicia faba andHyacinthus orientalis (1972)
    Springer
    Plant systematics and evolution 120 (1972), S. 15-28 
    Details
    ISSN: 1615-6110
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Summary Colchicine treatments change the rate of entry of cells into prophase in roots of bothVicia faba andHyacinthus orientalis. These changes have been discussed with respect to the effects of colchicine on cell progression through interphase. Since colchicine treatments alter the normal kinetics of cell entry into mitosis, the rate of accumulation of cells in metaphase following colchicine treatments cannot be used to determine cycle time in the species investigated in this study. Evidence is also presented showing that hyacinth roots are less sensitive to colchicine treatments than those of the broad bean.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01373255
    Standort Signatur Erwartet Verfügbarkeit
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