干旱区生态环境知识资源中心

Chenopodium album L., a salt-tolerant species that is widely distributed in the semi-arid areas of Xinjiang, China, produces numerous dimorphic seeds (black and brown). To investigate the effects of three salts (NaCl, KCl, and CaCl2, which constitute the main salt cations in the soil in semi-arid areas) on seed germination and seedling survival of C. album, seeds were germinated in different salinity treatments: 0, 100, 200, and 250 mmol.L-1 of NaCl or KCl; or, 300 and 400 mmol.L-1 NaCl or KCl, each amended with CaCl2 (0, 2.5, 5.0, 7.5, and 10.0 mmol.L-1). Results showed that the brown seeds were more salt tolerant, and a higher percentage germinated than black seeds in the different salinity treatments. The percentage of germinating of black seeds could be significantly improved, when under saline conditions, by the synergetic action of ethephon (C2H6ClO3P) and KNO3. The addition of low concentrations of CaCl2 improved seed germination for seeds exposed to 300 mmol.L-1 NaCl or KCl, and the alleviating effects were stronger for the brown than for the black seeds. Seedling survival could also be enhanced by the addtion of CaCl2. These results suggest that the dimorphic seeds of C. album exhibit different germination patterns under different salinity conditions, and that the diversity in salt tolerance of dimorphic seeds enables C. album to adapt to semi-arid areas successfully. The physiological mechanism by which CaCl2 enhances the germination of dimorphic seeds requires further study.