Consequences of depletion of stratospheric ozone for terrestrial Antarctic ecosystems: the response of Deschampsia antarctica to enhanced UV-B radiation in a controlled environment
2001
Rozema, J. | Broekman, R. | Lud, D. | Huiskes, A.H.J. | Moerdijk, T. | Bakker, N. de | Meijkamp, B. | Beem, A. van
Mini UV lamps were installed over antarctic plants at Leonie Island, Antarctic peninsula, and shoot length measurements of Deschampsia antarctica were performed during the austral summer January-February 1999. We studied the response of the antarctic hairgrass, Deschampsia antarctica to enhanced UV-B. In a climate room experiment we exposed tillers of Deschampsia antarctica, collected at Leonie Island, Antarctic peninsula, to ambient and enhanced levels of UV-B radiation. In this climate room experiment with 0, 2.5 and 5 kJ m(-2) day(-1) UV-B(BE) treatments we observed that length growth of shoots at 2.5 and 5 kJ m(-2) day(-1) UV-B(BE) was markedly reduced compared to 0 kJ m(-2) day(-1) UV-B(BE). In addition, there was an increased number of shoots and increased leaf thickness with enhanced UV-B. The Relative Growth Rate (RGR) was not affected by UV-B, possibly because reduced shoot length growth by enhanced UV-B was compensated by increased tillering. Light response curves of net leaf photosynthesis of plants exposed to 5 kJ m(-2) day(-1) UV-B(BE) did not differ from those exposed to 0 kJ m(-2) day(-1) UV-B(BE). The content of UV-B absorbing compounds of plants exposed to increasing UV-B did not significantly change. Mini UV-B lamp systems were installed in the field, to expose the terrestrial antarctic vegetation at Leonie Island to enhanced solar UV-B. In that study, the increment of shoot length of tagged plants of Deschampsia antarctica during the January-February 1999 at Leonie Island, was recorded and compared to shoot length growth under controlled conditions. The consequences of enhanced UV-B radiation as a result of ozone depletion for the terrestrial antarctic ecosystems are discussed.
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