We have focused mainly on recent work in order to highlight the progress made to date, and to attempt an analysis of the complexity of both independent and interacting factors on terrestrial ecosystems in terms of UV radiation and other environmental constraints, including emerging evidence of the role of stratospheric ozone trends in affecting climate.
Ozone depletion, changed exposure to ultraviolet-B (UV-B, 280–315 nm) radiation, and climate change exert both individual and interactive effects on biological systems, with intricate feedbacks.
1,2 Some of the key factors interacting with UV radiation that affect organism response are water availability, temperature, and nutrient availability. UV radiation has also been implicated as a contributor to global warming through its stimulation of volatile organic compounds from plants, plant litter and soils. Emission of carbon dioxide (CO2) from plant litter and soils may also contribute to global warming.
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During the course of research on the effects of UV radiation, much emphasis has been placed on the potential detrimental impacts on plants and ecosystems. However, the balance of recent evidence is shifting to show that while some detrimental effects do occur, UV radiation is also a key regulator of plant morphology and physiological, biochemical and genetic processes, and is important in animal and plant signalling. Following on from this line of investigation, it has also become apparent that UV radiation and climate variables can be usefully exploited for value-adding to, e.g., agricultural crops.
8 The emerging concept, that agricultural
2,9 plants can become more hardy through exposure to UV radiation, represents a marked shift in perspective.
8,9 In addition, certain plants produce more medicinal compounds with exposure to UV radiation.
10 The overall objective is to boost the quality and/or quantity of the yield, usually selectively, e.g. by making plants less prone to attack by pests and diseases. Concepts such as that of “eustress” are also relevant. Eustress is analogous to “priming” where a stress is imposed on plants to acclimate them and develop tolerance, which facilitates better growth when exposed to a more severe stress.
9,11