Short-term impacts of enhanced UV-B radiation on photo-assimilate allocation and metabolism: a possible interpretation for time-dependent inhibition of growth

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Type Article
Original languageEnglish
Pages (from-to)1-2
Number of pages2
JournalPlant Ecology
Issue number1-2
Publication statusPublished - 2001
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To test the hypothesis that plant source-sink relations are important in determining response to UV-B radiation, a short-term (45 d) field experiment was conducted at Abisko Scientific Research Station, Abisko, Sweden (68° N). Tillers of the grass Calamagrostis purpurea were grown outdoors at levels of UV-B radiation representing 25% ozone depletion. Growth, respiration, photo-assimilate allocation and UV-B protective compounds were subsequently measured. There were no significant effects of enhanced UV-B on total plant dry weight, leaf area, Shoot: Root ratio, leaf weight ratio, leaf area ratio, specific leaf area, tiller number per plant or blade thickness of this species. However, the amount of UV-B absorbing compounds and respiration rates were significantly increased in young and mature leaves. Increases in leaf respiration were accompanied by alterations in plant carbohydrate allocation at enhanced UV-B. The amount of soluble root carbohydrates was reduced following UV-B exposure. Enhanced UV-B also caused increases in the soluble sugar: starch ratio of young leaves, the stem and total aboveground biomass. The importance of source-sink relations and constitutive versus induced defense are discussed in relation to UV-B response.