Ecophysiology of Seed Germination in Composites Inhabiting Fire-prone Mediterranean Ecosystems [chapter]

M. A. Doussi, C. A. Thanos
1997 Current plant science and biotechnology in agriculture  
Within the framework of a research project concerning adaptive mechanisms of postflre regeneration in Mediterranean ecosystems, the ecophysiology of seed germination was studied ßç the following composites: Dittrichia viscosa (L.) Greuter, Helichrysum stoechas (L.) Moench ssp. barrelieri (Ten.) Nyman and Phágnalon gráecum Boiss. & Heldr. ÁÉÉ three species are common ßç the Mediterranean region; the former is a colonizer while the latter two are usually present ßç phrygana Qow-shrub, fire-prone
more » ... -shrub, fire-prone Mediterranean vegetation). As the result of their numerous, anemochorous dispersal units the three species are endowed with the potential Éï invade disturbed areas, ßç general, and burned ones, in particular. Germination ßç Dittrichia was generally very low ßç the dark (0-10%). Moreover, an absolute light requirement was revealed and germination could be promoted even by green safelight. Éç Helichrysum, final dark germination reached its highest value (ca. 500/0) at relatively low temperatures (10°C, 15°C). Light and nitrates (optimal concentration 20 mM) promoted germination dramatically above dark control. Nevertheless, fcll induction of germination required the presence of both these factors. Phágnalon germinated optimally (70-100%) over a broad temperature range (É 0-25°C), ßç the dark. However, light proved beneficial at suboptimal temperatures. Éç the three species studied, light and, ßç the case of Helichrysum, nitrate availability are particularly important for seed germination and eventual seedling recruitment ßç the postfire environment. R.H. Elli.r, Ì. ÂÉáÜ, ë.): Murdoch. 7:D. Hong (edr.). Basic áÌ Applied Aspec/s ï/ Seed ÂßïlÏÊÕ. ññ. 641-649. C 1997 KIuwer Acádemic Publi.rhers. Dordrech/. Prin/ed in Greát Britáin.
doi:10.1007/978-94-011-5716-2_71 fatcat:fbqutoawkzfyvowvaoo3s3poce