Germination and dormancy states of seeds in the environmental weed Rumex vesicarius (Polygonaceae). II. Germination and dormancy of seeds enclosed within the fruit
Andrea Schatral A B and Joan M. Osborne AA Mine Rehabilitation Group, Department of Environmental Biology, Curtin University of Technology, PO Box U1987, Perth, WA 6845, Australia.
B Corresponding author. Email: ascha@iprimus.com.au
Australian Journal of Botany 54(8) 783-789 https://doi.org/10.1071/BT04202
Submitted: 7 December 2004 Accepted: 22 May 2006 Published: 29 November 2006
Abstract
Rumex vesicarius (Ruby dock; subgenus Acetosa, section Vesicarii, family Polygonaceae) shows fascinating ways of controlling and staggering seed germination throughout the year. Seeds within the large inflated fruiting valves (fruits) display variations in their ability to germinate, which are related to the time of the year and depend on the presence of light. Perianth-imposed dormancy appears to undergo one distinct seasonal cycle under laboratory conditions. Our results suggest that germination is best during the autumn and winter months but poor during the rest of the year. In the natural environment (fruits either remain on the soil surface or are buried) dormancy release may be occurring several times during the year under appropriate light, temperature and moisture conditions. Preliminary experiments indicate that the fruiting valves produce chemical substances that inhibit seed germination, and their break down appears to be affected by light.
Acknowledgments
This study was generously supported by the Mining, Energy and Research Institute of Western Australia (MERIWA 332). We are also grateful to the Environmental officers of the participating mining companies, especially to Ms Fleur Izet (Plutonic/ Homestake Gold of Australia Ltd, Meekatharra), Mr David Button, Mr John Robinson, Mr Nathan Russell (Placer/ Delta Gold NL) and Ms Bethany Challen (Granite Gold, Alice Springs) for seed material and soil samples.
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