| Popis: |
A phytocenose of a natural Mediterranean ecosystem (wood and garrigue * ), undisturbed by man for a third of a century, has been subjected to chronic gamma radiation (source 137caesium) since July 12th 1969. This experiment has been set up at the Nuclear Research Centre at Cadarache. Some similar experiments have already been carried out, but with different types of ecosystems. The first results obtained up till the date of writing agree with the results obtained on different types of ecosystems, at least in the fields of morphology (leaf malformation and stem shortening), anatomy (meristem inhibition, tissue distortion) and radiosensitivity (the herbaceous plants are more resistant than ligneous plants). It should also be noted that surviving foliage which had grown before the radiation began displayed a high radiosensitivity in general, and that thallophytes (lichens) showed an increased rate of growth in the space left free by the death of higher plants (especially ligneous plants). The authors noted that the typical Mediterranean species were more resistant, while the submediterranean species appeared more sensitive, and this is apparent in the classification of the species by degree of sensitivity. It appears that in this case, the ecological environmental characteristics are as important as the standard factors already known, if not more so, in determining a plant's radiosensitivity. |
