Role of the lens in physical dormancy in seeds of Sophora alopecuroides L. (Fabaceae) from north-west China
X. W. Hu A , Y. R. Wang A D , Y. P. Wu A , Z. B. Nan A and C. C. Baskin B CA College of Pastoral Agricultural Science and Technology, Key Laboratory of Grassland and Agro-ecosystem, Ministry of Agriculture, Lanzhou University, Lanzhou 730020, China.
B Department of Biology, University of Kentucky, Lexington, Kentucky 40506-0225, USA.
C Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312, USA.
D Corresponding author. Email: yrwang@lzu.edu.cn
Australian Journal of Agricultural Research 59(6) 491-497 https://doi.org/10.1071/AR07265
Submitted: 13 July 2007 Accepted: 7 February 2008 Published: 10 June 2008
Abstract
Although many studies have been done on seeds with physical dormancy, i.e. water-impermeable seed or fruit coat, the primary site of water entry into seeds after dormancy-breaking treatments is still controversial. In this work, the role of the lens in physical dormancy breaking was examined.
The present study investigated the primary site of water entry and changes in seed-surface features for seeds of Sophora alopecuroides L. following various periods of scarification with sulfuric acid, hot-water treatments, and exposure to field conditions.
Most seed coats first cracked in the hilum when pre-treated with sulfuric acid and after field exposure, but they cracked in both the hilum and extrahilar regions when treated with hot water. After pre-treatment, seeds first became slowly permeable in the hilum or extrahilar region and not in the lens. Acid scarification for 35 or 50 min caused the lens to crack, thus causing seeds to enter a fast imbibition stage. Seeds exposed to field conditions had further damage to the hilum, causing them to enter a fast imbibition stage.
Imbibition time is a key point that determines the primary site of water entry into seed, and at least in part explains various results and interpretations about the role of the lens in physical dormancy in previous research.
Additional keywords: field exposure, hot water, hilum, imbibition time, primary site of water entry, sulfuric acid.
Acknowledgments
We thank Mr Zhang Baolin for his help in the seed collection and field work. The study was funded by the National Key Basic Research Special Foundation Project of China (2007CB108904) and the Natural Science Foundation of China (30771532).
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