<br/>The parameters used were survival of irradiated leaves of <em>S. ionantha</em> , production of adventitious plantlets at the base of the petiole and mutation frequency.<p/>The differences between unfiltered X-rays from a 250/25 deep therapy apparatus and fast neutrons from a degraded fissions spectrum was slight and sometimes negligible. A striking dose rate effect was observed, especially with X-rays. In fractionation experiments a protective mechanism was induced in the leaves by pre-irradiation with either type of radiation. This mechanism reached a maximum after 8-12 h. Then the extent of the protection was equivalent to 3 krad X-rays or 1.5 krad fast neutrons after a single pre-treatment with the optimum initial dose of 500 rad, X-rays or fast neutrons. A 10-15 fold irradiation with this dose, separated by 8-h intervals, induced a protection of 6-7 krad X-rays or 3-4 krad fast neutrons.<p/>Several of the treatments result in a higher number of mutants per 100 irradiated leaves compared with the optimum acute dose of 3 krad X-rays or 1.5 krad fast neutrons.
|Qualification||Doctor of Philosophy|
|Award date||23 Jun 1972|
|Place of Publication||Wageningen|
|Publication status||Published - 1971|
- ornamental plants
- plant breeding
Broertjes, C. (1971). Use in plant breeding of acute, chronic or fractionated doses of X-rays or fast neutrons as illustrated with leaves of Saintpaulia. Wageningen: Centre for Agricultural Publishing and Documentation.