Eryngium maritimum is a coastal plant of the Apiaceae family. This species is threatened in several countries where it reaches the northern limits of its distribution area. Existing populations in the Baltic Region and Scandinavia are potentially affected by the low efficiency of its generative reproduction. We studied physiological aspects of its germination and dormancy breaking requirements using seeds collected from two Latvian populations. Seeds were subjected to cold and warm stratification and treatment with gibberellic acid. We monitored the development of seed embryos throughout the process of stratification at different temperatures and built a size-class structure of embryo development within a batch of seeds to visualize the developmental progress and to compare different treatments. The final germination percentage and germination rate increased after cold stratification at 5 °C in seeds germinated at 25/10 °C. Maximum germination was achieved after four months of cold stratification. Treatment with gibberellic acid had a similar dormancy breaking effect that was enhanced by previous warm stratification. The relative size of embryos increased during cold stratification, although this increase was not uniform. We conclude that in seeds of E. maritimum, embryo growth during stratification is required before germination can start and that growth is enhanced by warm stratification. Breaking the physiological component of seed dormancy requires cold stratification that can be substituted by treatment with gibberellic acid. We suggest that germination characteristics of seeds and the structure of embryo development within seeds in a particular population may reflect the state of the plant population itself and provide valuable information for research on the biology of this species.
Adams, C. A., Baskin, J. M. & Baskin, C. C. 2011. Using size-class structure to monitor growth of underdeveloped embryos in seeds of three Aristolochia species: implications for seed ecology. Seed Science Research, 21, 159–164.
http://dx.doi.org/10.1017/S0960258511000018
Andersone, U., Druva-Lusite, I., Ieviņa, B., Karlsons, A., Necajeva, J., Samsone, I. & Ievinsh, G. 2011. The use on nondestructive methods to assess a physiological status and conservation perspectives of Eryngium maritimum L. Journal of Coastal Conservation, 15, 509–522.
http://dx.doi.org/10.1007/s11852-010-0139-7
Aviziene, D., Pakalnis, R. & Sendzikaite, J. 2008. Status of red-listed species Eryngium maritimum L. on the Lithuanian coastal dunes. In Environmental Engineering: Proceedings of the 7th International Conference, May 2008, pp. 22–28. Vilnius Gediminas Technical University.
Baskin, J. M. & Baskin, C. C. 2004. A classification system for seed dormancy. Seed Science Research, 14, 1–16.
http://dx.doi.org/10.1079/SSR2003150
Curle, C. M., Stabbetorp, O. E. & Nordal, I. 2007. Eryngium maritimum, biology of a plant at its northernmost localities. Nordic Journal of Botany, 24, 617–628.
Fatare, I. 2003. Eryngium maritimum L. In Red Data Book of Latvia, Volume 3, Vascular Plants (Andrušaitis, G., ed.), pp. 278–279. Riga.
Fenner, M. & Thompson, K. 2005. The Ecology of Seeds. Cambridge University Press.
http://dx.doi.org/10.1017/CBO9780511614101
Finch-Savage, W. E. & Leubner-Metzger, G. 2006. Seed dormancy and the control of germination. New Phytologist, 171, 501–523.
http://dx.doi.org/10.1111/j.1469-8137.2006.01787.x
Gaudeul, M. & Till-Bottraud, I. 2003. Low selfing in a mass-flowering, endangered perennial, Eryngium alpinum L. (Apiaceae). American Journal of Botany, 90, 716–723.
http://dx.doi.org/10.3732/ajb.90.5.716
Labuz, T. A. 2007. Evaluation of past and present sea holly (Eryngium maritimum) habitats on Polish coastal dunes. Acta Universitatis Latviensis, 723, 99–114.
Nikolaeva, M. G., Rasumova, M. V. & Gladkova, V. N. 1985. Reference Book on Dormant Seed Germination. Nauka, Leningrad (in Russian).
Olsauskas, A. 1996. Influence of Recreation on Plant Cover in West Lithuania. Klaipeda University.
Royal Botanic Gardens Kew. 2008. Seed Information Database (SID). Version 7.1. http://data.kew.org/sid/ (accessed 17.07.2009).
Vandelook, F, Bolle, N. & Van Assche, J. A. 2009. Morphological and physiological dormancy in seeds of Aegopodium podagraria (Apiaceae) broken successively during cold stratification. Seed Science Research, 19, 115–123.
http://dx.doi.org/10.1017/S0960258509301075
Van der Maarel, E. & Van der Maarel-Versluys, M. 1996. Distribution and conservation status of littoral vascular plant species along the European coasts. Journal of Coastal Conservation, 2, 73–92.
http://dx.doi.org/10.1007/BF02743039
http://dx.doi.org/10.2307/2404854
