Chin J Plant Ecol ›› 2012, Vol. 36 ›› Issue (8): 781-790.DOI: 10.3724/SP.J.1258.2012.00781

• Research Articles • Previous Articles     Next Articles

Adaptive strategies of dimorphic seeds of the desert halophyte Suaeda corniculata in saline habitat

YANG Fan1,2, CAO De-Chang1,2, YANG Xue-Jun1, GAO Rui-Ru1,2, HUANG Zhen-Ying1,*()   

  1. 1State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    2Graduate University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2012-03-09 Accepted:2012-04-30 Online:2012-03-09 Published:2012-08-21
  • Contact: HUANG Zhen-Ying


Aims Suaeda corniculata (Chenopodiaceae) is an annual halophyte in salt marshes and saline deserts of northern China. It produces two distinct types of seeds (brown and black). The primary aims of our study were to compare the morphology, dormancy and germination characteristics of dimorphic seeds of S. corniculata in order to elucidate adaptive strategies of the desert halophyte in stressful saline habitat.
Methods Seeds were collected in saline habitats in Otog, Nei Mongol. The dimorphic seeds were incubated in different temperature regimes, light and salinity (NaCl) conditions to determine their germination responses. The effects of cold stratification and seed coat scarification on dormancy breaking of black seeds were also tested.
Important findings Dimorphic seeds were different in seed mass and testa morphology. Brown seeds were bigger and more permeable to water than black seeds. Seed ratio was 5.6 : 1 (black seeds : brown seeds). Freshly matured brown seeds had a high germination percentage (84%-100%) in all temperature regimes and under either light or dark conditions. By contrast, black seeds had a lower germination percentage (8%-78%) than brown seeds in all temperature regimes, and germination was increased in light. Seed coat scarification, GA3 treatments and cold stratification significantly increased the germination of black seeds, suggesting that black seeds had non-deep physiological dormancy. Responses of dimorphic seeds to saline stress were different. Brown seeds were more salt-tolerant than black seeds and germinated at a high germination percentage in high salt concentrations. Cold stratification reduced the sensitivity of black seeds to salt stress and increased the initial germination percentage, recovery and final germination in salt solutions. The differences in morphology, dormancy and germination characteristics between dimorphic seeds of S. corniculata increased the species’ fitness to heterogeneous habitats and formed an ecological adaptive strategy that may allow S. corniculata to successfully adapt to the harsh desert habitat.

Key words: desert halophyte, saline habitat, seed dimorphism, seed germination, seed physiological dormancy, Suaeda corniculata