Depletion of the ozone layer is likely to inflict lasting genetic damage to plant life through exposure to strong ultraviolet light, according to research.
High levels of ultraviolet B caused DNA damage and mutations among tobacco plants and thale cress in laboratory conditions, Swiss and German scientists report in Thursday's issue of Nature, the British science weekly.
And in a small but significant number of plants, mutations occurred in the reproductive cells, meaning that the changes were handed on to subsequent generations.
The findings go far beyond previous work which said ultraviolet bleaches chlorophyll in leaves and stunts plant growth but found no evidence that ensuing generations could be affected.
"The events observed here may represent the tip of a mutational iceberg," commented plant biologist Anne Britt of the University of California at Davis.
"This study presents intriguing data suggesting that depletion of the ozone layer may have a measurable effect on the mutation rate of at least some plants."
The research was conducted by researchers from Friedrich-Miescher-Institut in Basel, Switzerland and the GSF-Forschungszentrum fuer Umwelt und Gesundheit in Neuherberg, Germany.
They inserted a so-called "reporter" gene in the plants in which any cells that suffered changes to short DNA sequences would be stained blue, making them immediately apparent to the naked eye.
The work adds to previous knowledge about the damaging effect of UV-B on human DNA.
Many people who sunbathed intensively in the 1960s and 70s are now paying the price with skin cancer -- cells whose DNA has been turned malignant by exposure to strong ultraviolet light.
The ozone layer in the Earth's atmosphere helps protect life by filtering out ultraviolet light, especially in the UV-B wavelength of 280-320 nanometres.
Ozone molecules are under attack from chloro-fluorocarbons (CFCs), gases that are used commercially as aerosol propellants, refrigerants, cleansing agents and foaming agents in the manufacture of plastics -- PARIS (AFP)
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