| Abstrakt: |
A study was made of colchicine effect on genetic and morphological stability of morphogenic calli of the tatar buckwheat Fagopyrum tataricum (L.) Gaertn. A prolonged exposure of the morphogenic callus in colchicins-containing medium led to its morphological changes: the callus became more friable, and proembryogenic cell complexes disappeared. Genetic non-stability started from the first days of culturing in colchicine-containing indicated by amitotic divisions and K-mitoses, leading to the formation of micronuclei and increased variability in chromosome number. As a result of colchicine action, a few lines of heterogeneous calli were obtained differing in morphology, chromosome numbers, and ability to morphogenesis from the primary morphogenic callus. Genetic instability appeared in the following passages, when the treated calli were subcultured in the medium without colchicine: a wide range of abnormal nuclear division and chromosome aberrations was observed. This prolonged genetic instability was accompanied by a prominent increase in the formation of friable clones, which was 20-30 times higher than in the control. The formation of friable clones seems to result from one or two point mutations. |
