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

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.