Exposure to ultraviolet (UV) radiation is generally regarded to be deleterious to biological systems; however – like many potentially bad things – in small doses it may actually be beneficial. Well, that is what Jason Wargent and co-workers have found (Plant, Cell & Environment, 2011).
The UK-based research found that exposure of lettuce (Lactuca sativa) to UV-B in the early stages of growth led to increased photosynthetic activity and consequently higher yield(!). Or, in the more guarded parlance of the scientific paper, ‘Our findings suggest that earlier exposure to realistic levels of UV radiation leads to positive photosynthetic performance and other protective changes in leaf morphology, and when combined with enhanced photoprotection to high light and temperature as observed under controlled conditions, these early-stage effects driven by UV-B appear to enhance plant tolerance against generalized field transplantation stresses to a greater capacity, which can then lead to increased productivity in a longer-term field growth environment’.
Rather than repeat that, and in case you’ve missed the potential importance of this finding, the article’s abstract usefully concludes thus, ‘Our findings are discussed within the context of sustainability in agriculture and the paradigm shift in photobiology [slight emphasis added by me] which such beneficial responses to UV radiation could represent’(!!). And – because I know you’re wondering – I’m not aware that the famous leafy culinary vegetable’s green colouration was darkened by the treatment (by analogy to the tanning effect that occurs in human epidermides upon exposure to UV). So, your principal salad component should still be green (though why anybody eats the unsatisfying so-called foodstuff in the first place is beyond me).