Effects of salinity and temperature on Deschampsia antarctica
- 202 Downloads
Deschampsia antarctica is one of two species of vascular plants native to Antarctica. Populations of D. antarctica have become established on recently exposed glacial forelands on the Antarctic Peninsula and these plants may rely upon nutrient inputs from hauled out mammals, seabirds and sea spray. However, not much is known about the ability of these plants to tolerate salinity stress. We examined the effects of salinity and temperature on growth, reproduction, chlorophyll fluorescence and water relations of D. antarctica. In addition, we analysed concentrations of free proline in leaves and roots as previous studies have found large increases in the concentration of this amino acid in response to environmental stress. The growth chamber experiment was a 3 × 3 (temperature × salinity) complete factorial. Plants were grown at three temperature regimes: 7°/7°C, 12°/7°C, and 20°/7°C day/night and three salinity levels: <0.02 decismen per metre (dS m−1; “low salinity”), 2.5 dS m−1 (“medium salinity”), and 5.0 dS m−1 (“high salinity”) for 66 days. Warmer temperatures improved leaf and tiller production as well as leaf and root length, which is consistent with previous findings on this species. Salinity reduced final root length by 6 and 13% in the medium and high-salinity treatments, respectively. Plants growing in medium and high-salinity treatments had xylem pressures that were more negative and higher free-proline concentrations, suggesting that proline may act as an osmoregulant in D. antarctica.
KeywordsDeschampsia antarctica Osmoregulation Proline Salt tolerance Soil salinity Temperature
This research was supported by the National Science Foundation Office of Polar Programs (Grant OPP-0230579) and a Summer Research Grant from The College of Graduate Studies and Research at Minnesota State University to CTR. We thank Mary Morgan for assistance with proline determinations and Drs. Thomas A Day and Fusheng Xiong for assistance with seed collection.
- Convey P (1996) Reproduction of Antarctic flowering plants. Antarct Sci 8:127–134Google Scholar
- Convey P, Smith RIL (2006) Responses of terrestrial Antarctic ecosystems to climate change. Plant Ecol 182:1–10Google Scholar
- Edwards JA (1972) Studies in Colobanthus quitensis (Kunth) Bartl. and Deschampsia antarctica Desv: V. Distribution, ecology and vegetative performance on Signy Island. Br Antarct Surv Bull 28:11–28Google Scholar
- Heuer B (1999) Osmoregulatory role of proline in plants exposed to environmental stresses. In: Pessarakli M (ed) Handbook of plant and crop stress, 2nd edn. Marcel Dekker, Inc, New York, pp 675–695Google Scholar
- Passioura JB, Munns R (2000) Rapid environmental changes that affect leaf water status induce transient surges or pauses in leaf expansion rate. Aust J Plant Physiol 27:941–948Google Scholar
- Ruhland C, Strauss S, Krna M, Day T (2006) The effects of supplemental warming and precipitation on growth and reproduction of Antarctic vascular plants. In: Abstracts of the ecological society of America. Annual Meeting Memphis, TN. Available via ESA. http://abstracts.co.allenpress.com/pweb/esa2006/document/61672. Accessed 15 May 2009
- Smith RIL (2003) The enigma of Colobanthus quitensis and Deschampsia antarctica in Antarctica. In: Huiskes AHI, Gieskes WWC, Rozema J, Schorno RML, van Der Vies SM, Wolff WJ (eds) Antarctic biology in a global context Leiden. Backhuys Publishers, The Netherlands, pp 234–239Google Scholar