The influence of cytokinins on genetic tumor formation

1972 ◽  
Vol 50 (11) ◽  
pp. 2235-2238 ◽  
Author(s):  
Ira H. Ames

Young seedlings of two tumor-prone Nicotiana amphiploids, grown aseptically on nutrient medium, were treated with either N6-benzyladenine or kinetin. The incidence of tumor formation was scored for 18 days subsequent to exposure. These cytokinins markedly accelerated the rate of tumorigenesis in both amphiploids. The results are discussed in relation to the problem of the trigger mechanism for tumor induction in Nicotiana species hybrids.

1970 ◽  
Vol 48 (12) ◽  
pp. 2209-2212 ◽  
Author(s):  
Ira H. Ames

Young seedlings of two tumorous Nicotiana amphiploids and the parental species, grown aseptically on nutrient medium, were treated with 2,3,5-triiodobenzoic acid. The incidence of tumor formation was scored for 18 days subsequent to exposure. Triiodobenzoic acid markedly accelerated the rate of tumorigenesis in both amphiploids, but it did not induce tumors in the parental species. The compound also induced tumor formation in a small percentage of seedlings of a non-tumorous mutant of the N. glauca × N. langsdorffii amphiploid. These results are discussed in relation to the problem of the trigger mechanism for tumor induction in Nicotiana species hybrids.<


1971 ◽  
Vol 49 (9) ◽  
pp. 1699-1701 ◽  
Author(s):  
Ira H. Ames

Young seedlings of the amphiploid Nicotiana suaveolens × N. langsdorffii, grown aseptically on nutrient medium, were treated with several concentrations of gibberellic acid (GA3). The incidence of tumor formation was scored for 18 days subsequent to exposure. At a concentration of 5 × 10−3 M, GA3 caused a striking reduction in the rate of tumor formation and a marked enhancement of stem growth in this tumor-prone amphiploid. These results are discussed in relation to the problem of the trigger mechanism for tumor induction in Nicotiana hybrids.


1969 ◽  
Vol 47 (6) ◽  
pp. 921-924 ◽  
Author(s):  
I. H. Ames ◽  
H. H. Smith

Young seedlings of the amphiploid Nicotiana glauca × N. langsdorffii, grown aseptically on nutrient medium, were treated with solutions containing 2-mercaptoethanol, and the incidence of tumor formation was scored for 30 days subsequent to exposure. Mercaptoethanol caused a marked acceleration in the rate of tumorigenesis when the pH of the test solution was in the alkaline range. The effectiveness of the compound was reduced by lowering the pH of the treatment solution.


1970 ◽  
Vol 25 (7) ◽  
pp. 735-738 ◽  
Author(s):  
Rolf Beiderbeck

Concentrations of 10 µg/ml rifampicin reduce the growth of Agrobacterium tumefaciens by more than 90%, concentrations of 100 µg/ml prevent tumor formation in Kalanchoë daigremontiana by the same bacteria.A treatment with rifampicin does not irreversibly alter the bacteria; after removal of the drug bacterial propagation and the ability of tumor induction are restored.0-24 h treatments of the plant wounds with rifampicin prior to infection prevent tumor formation completely.Addition of rifampicin after infection inhibits tumor formation optimally if the drug is added only few hours after inoculation. 30 h after infection the bacteria-host-system is resistant against rifampicin.100 μg/ml rifampicin do not influence the growth of already induced tumors.


CYTOLOGIA ◽  
1934 ◽  
Vol 5 (3) ◽  
pp. 373-377 ◽  
Author(s):  
Dontcho Kostoff

1976 ◽  
Vol 31 (5-6) ◽  
pp. 317-318 ◽  
Author(s):  
Rolf Beiderbeck

Tumor induction by Agrobacterium tumefaciens on Kalanchoe leaves is suppressed by charcoal mixed with the inoculum. The inhibition works best with a certain mass relation between bacteria and charcoal. The bacteria become adsorbed to the charcoal particles and in this state they are unable to induce tumors. If charcoal is added to bacteria-infected wounds only 15 min after infection it is not interfering with tumor formation. These results are supporting the hypothesis of sites in the wound to which Agrobacterium has to be attached to incite tumors.


1950 ◽  
Vol 28c (3) ◽  
pp. 277-282 ◽  
Author(s):  
L. C. Coleman

In a search for suitable material for a cytological study of plant tumors, pure and virulent cultures of Agrobacterium tumefaciens were inoculated into stems of young Vicia faba plants without result. On the other hand, a bacterium isolated from Himalaya blackberry produced large tumors. A comparison of the two forms as to their virulence on other plant species showed that the blackberry organism would not attack tomato, Nicctiana glutinosa, and Datura medeloides, all highly susceptible to A. tumefaciens. Sunflower proved to be a common host to the two pathogens, but the host responses showed significant differences. The tumors caused by the blackberry organism were smaller and were not accompanied by epinasty of the leaves immediately above the tumor, a characteristic feature associated with tumor formation induced by A. tumefaciens. From cultural characters and differences in host range, it was decided that the blackberry organism belongs to Agrobacterium rubi (Hildebrand) Starr & Weiss., a species considered as confined to Rubus species. Its host range is obviously much wider than this and, as it embraces plants only slightly or not at all susceptible to A. tumefaciens, it is likely to prove an important addition to this species in providing material for the study of plant tumors.


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