NUCLEAR TECHNIQUES AND IN- VITRO CULTURE FOR PLANT IMPROVEMENT
A synthesis is given of all the results obtained by the Biology Group of the Joint Research Centre, Ispra, during the last few years regarding the effects of various kinds of ionizing radiation on large populations of Nicotiana plumbaginifolia protoplasts. After a critical assessment of the protoplast system as a tool for radiosensitivity studies, a description is given of the dose effect relationship (RBE) and split dose effects after gamma ray and fast neutron irradiation. Among the results obtained, it was noted that fractionation of gamma ray doses allowed a substantial recovery, while fractionation of a fast neutron dose into low single fractions markedly increased the biological effectiveness of the total dose. Dose-response curves were also obtained for irradiated haploid protoplasts. Cell sizing, Feulgen cytophotometry and 3-H-thymidine labelling were used to describe cellular heterogeneities pre-existing in original tissues and transmitted to the protoplast culture. Dissection of leaf tissue into its more or less differentiated territories and purification of the protoplasts in various phases of an iso-osmotic density gradient made it possible to separate subpopulations with definite characteristics. Among these, radiosensitivity gave a quite homogeneous response for each subpopulation. In order to analyse the radiosensitivity of tissues at various differentiation stages, the radiation response of protoplasts freshly isolated from leaf tissue was compared with the response of protoplasts from very young calluses. The differences were quite evident and show that the differentiated leaf cells are much more sensitive than the proliferating cells of young calluses.
Bibliographic Reference: EFFECTS OF IONIZING RADIATIONS ON PLANT CELLS CULTURED IN-VITRO, WIEN (AUSTRIA) AUG. 19-23, 1985, PUBL. IN "NUCLEAR TECHNIQUES AND IN-VITRO CULTURE FOR PLANT IMPROVEMENT" BY IAEA, 1986, PP. 93-101
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Record Number: 1989124115100 / Last updated on: 1987-01-01
Available languages: en