Effects of Light and Temperature On Germination of Pyxidanthera brevifolia Wells (Diapensiaceae)

Document Type

Article

Publication Date

10-1-2010

Department

Coastal Sciences, Gulf Coast Research Laboratory

Abstract

WALL, W. A. (Department of Plant Biology, North Carolina State University, Box 7612, Raleigh, NC 27695), J. L. HILTON (Coastal Sciences Department, University of Southern Mississippi, Hattiesburg, MS 39406), T. R. WENTWORTH (Department of Plant Biology, North Carolina State University, Box 7612, Raleigh, NC 27695), J. B. GRAY (Endangered Species Branch, Fort Bragg, NC 28310), M. G. HOHMANN (US Army Corps of Engineers, Engineer Research and Development Center, Box 9005, Champaign, IL 61826), and W. A. HOFFMANN (Department of Plant Biology, North Carolina State University, Box 7612, Raleigh, NC 27695). Effects of light and temperature on germination of Pyxidanthera brevifolia B.W. Wells (Diapensiaceae). J. Torrey Bot. Soc. 137: 348-354. 2010.-Pyxidanthera brevifolia is an evergreen semi-woody cushion plant endemic to the Sandhills of North and South Carolina, with the majority of populations occurring on Fort Bragg Military Reservation in North Carolina. Currently the species is listed as Endangered in North Carolina and is designated as a Species at Risk (SAR) by the US Department of Defense. Previous studies have suggested that seeds may not be viable because they failed to germinate under controlled conditions. Our objectives in this study were to attempt germination of Pyxidanthera brevifolia seeds, determine the best temperature conditions for germination, and understand more about germination requirements to aid in future restoration efforts. Using seeds that had been stored at room temperature for six months, we performed a germination experiment at the NCSU Phytotron with six treatments, all combinations of three temperature regimes (low (18 degrees C day / 14 degrees C night), medium (22/18 degrees C), and high (26/22 degrees C)) and two light conditions (light and dark). We monitored the experiment for 13 weeks, recording the number of seeds germinating per dish and the number of days to germination for seeds in each treatment. We found that Pxyidanthera brevifolia produces germinable seeds and that there are significant effects of light and temperature on germination. Highest germination occurred under low temperature and high light conditions (78%); the combination of high temperature and no light produced the lowest germination (6%). Seeds exposed to light germinated significantly earlier at the coolest temperature, compared to medium and high temperatures. These results indicate that it is possible to germinate seeds of this rare plant and suggest that germination of Pyxidanthera brevifolia likely occurs in late fall and is dependent on adequate light availability.

Publication Title

Journal of the Torrey Botanical Society

Volume

137

Issue

4

First Page

348

Last Page

354

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