TY - JOUR
T1 - Influence of solar ultraviolet-B radiation on Antarctic terrestrial plants
T2 - Results from a 4-year field study
AU - Day, Thomas
AU - Ruhland, C. T.
AU - Xiong, F. S.
N1 - Funding Information:
We thank field team members Carl Grobe, Jenny Lin, Erin Mueller and Kirt Karl for the outstanding support they provided and their perseverance under challenging field conditions. Tuyetlan Nguyen, Lauren Griffen, Maria Wiehe, Erin Foley and Hana Dostalova assisted in laboratory analyses of samples and data. We also thank personnel of Antarctic Support Associates for logistical support, Biospherical Instruments for UV-B spectral data from the SUV-100 spectroradiometer at Palmer Station, and two anonymous reviewers for useful comments on the manuscript. This work was supported by National Science Foundation grants OPP-9596188 and 9615268.
PY - 2001/9/1
Y1 - 2001/9/1
N2 - We examined the influence of solar ultraviolet-B radiation (UV-B; 280-315 nm) on the performance of Antarctic vascular plants (Colobanthus quitensis and Deschampsia antarctica) by placing filters that either absorbed or transmitted most solar UV-B over tundra along the Antarctic Peninsula for four consecutive growing seasons. The difference in biologically effective UV-B levels between our treatments was 65%, which was similar to the enhancement in ambient UV-B levels that appeared attributable to ozone depletion during the first 2 months of the growing season (November and December) at our site (62%). In both species, exposure to UV-B reduced vegetative growth, primarily through slower leaf elongation rates that led to shorter fully expanded leaves. In C. quitensis, exposure to UV-B also led to reductions in leaf longevity, branch production, cushion diameter growth, aboveground biomass, and thickness of the non-green cushion base and litter layer. Exposure to UV-B accelerated the development of reproductive structures and increased the number of panicles (D. antarctica) and capsules (C. quitensis) that reached maturity per unit of ground surface area covered by mother plants. However, this effect was offset by a tendency for these panicles and capsules to produce fewer spikelets and seeds. Ultimately, UV-B exposure did not effect the numbers of spikelets or seeds produced per unit of ground surface area. While seeds from plants exposed to UV-B tended to be lighter, germination rates were similar between UV-B treatments. The relative reductions in leaf elongation rates in D. antarctica attributable to UV-B exposure increased from the first (23%) through the fourth (43%) growing season, and relative reductions in leaf longevity in C. quitensis tended to increase from the first (9%) through the fourth (19%) growing season, suggesting that UV-B growth responses tended to be cumulative over successive years.
AB - We examined the influence of solar ultraviolet-B radiation (UV-B; 280-315 nm) on the performance of Antarctic vascular plants (Colobanthus quitensis and Deschampsia antarctica) by placing filters that either absorbed or transmitted most solar UV-B over tundra along the Antarctic Peninsula for four consecutive growing seasons. The difference in biologically effective UV-B levels between our treatments was 65%, which was similar to the enhancement in ambient UV-B levels that appeared attributable to ozone depletion during the first 2 months of the growing season (November and December) at our site (62%). In both species, exposure to UV-B reduced vegetative growth, primarily through slower leaf elongation rates that led to shorter fully expanded leaves. In C. quitensis, exposure to UV-B also led to reductions in leaf longevity, branch production, cushion diameter growth, aboveground biomass, and thickness of the non-green cushion base and litter layer. Exposure to UV-B accelerated the development of reproductive structures and increased the number of panicles (D. antarctica) and capsules (C. quitensis) that reached maturity per unit of ground surface area covered by mother plants. However, this effect was offset by a tendency for these panicles and capsules to produce fewer spikelets and seeds. Ultimately, UV-B exposure did not effect the numbers of spikelets or seeds produced per unit of ground surface area. While seeds from plants exposed to UV-B tended to be lighter, germination rates were similar between UV-B treatments. The relative reductions in leaf elongation rates in D. antarctica attributable to UV-B exposure increased from the first (23%) through the fourth (43%) growing season, and relative reductions in leaf longevity in C. quitensis tended to increase from the first (9%) through the fourth (19%) growing season, suggesting that UV-B growth responses tended to be cumulative over successive years.
KW - Antarctica
KW - Colobanthus quitensis
KW - Deschampsia antarctica
KW - Leaf expansion
KW - Litter
KW - Ozone depletion
KW - Reproduction
KW - UV-B radiation
UR - http://www.scopus.com/inward/record.url?scp=0035449636&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0035449636&partnerID=8YFLogxK
U2 - 10.1016/S1011-1344(01)00161-0
DO - 10.1016/S1011-1344(01)00161-0
M3 - Article
C2 - 11693369
AN - SCOPUS:0035449636
SN - 1011-1344
VL - 62
SP - 78
EP - 87
JO - Journal of Photochemistry and Photobiology B: Biology
JF - Journal of Photochemistry and Photobiology B: Biology
IS - 1-2
ER -