Full Length Research Paper

Effect of saturation on seed dormancy and germination of the halophyte Leymus chinensis

Sun Yan-Lin^1,2, Jin Cheng-Wu² and Hong Soon-Kwan^2,3*

¹School of Life Sciences, Ludong University, Yantai, Shandong, 264-025, China.

²Department of Bio-Health Technology, College of Biomedical Science, Kangwon National University, Chuncheon, Kangwon-Do, 200-701, Korea.

³Institute of Bioscience and Biotechnology, Kangwon National University, Chuncheon, Kangwon-Do, 200-701, Korea.

*Corresponding author. E-mail: soonkwan@kangwon.ac.kr. Tel: +82 33 250 6476. Fax: +82 33 250 6470.

Abbreviations: HPLC, High-performance liquid chromatography; UV, ultraviolet; ABA, abscisic acid; PEG, polyethylene glycol; GA₃, gibberellic acid; 6-BA, 6-benzyladenine; MS, Murashige and Skoog; ANOVA, analysis of variance.

Accepted 16 December, 2011

   Abstract

The halophyte, Leymus chinensis (Trin.) a perennial rhizomatous grass, is widely distributed in northern China, Mongolia and Siberia. Due to its ecological and economical significance, understanding the underlying causes of the low fecundity and long-term seed dormancy that are characteristic of L. chinensis is critical for promoting propagation and germination of this grass. This study investigates the effect of saturation treatments of mature seeds on breaking seed dormancy and increasing germination in L. chinensis. The germination rates were significantly increased to 33.81, 46.15 and 50.35% from LcWT07-1, LcWT07-2 and LcJS0107, respectively after saturation treatments at 4°C for 3 days, suggesting that germination inhibitor components had been lixiviated from seed coats and/or mature seeds. High-performance liquid chromatography (HPLC) and ultraviolet (UV) analysis demonstrated that acidic components were lixiviated from both seed coats and dehusked mature seeds. Since dehusking also promotes seed germination, we predicted that the seed coat-derived soluble components contained germination inhibitors. Indeed, when L. chinensis plantlets were watered with the lixiviated solutions, their germination, but not their growth and development, was inhibited. Taken together, this work provides valuable insight into the regulation of seed dormancy and germination rate in L. chinensis, which may in turn have implications for improved propagation.

Key words: Saturation treatment, HPLC, UV, seed dormancy, germination, Leymus chinensis.