Effects of sodium salt stress on seed germination of typical annuals in a desert-oasis ecotone of Hexi Corridor, China

Abstract

We assessed the effects of different concentrations of salts (0, 40, 80, 120, 160 and 200 mmol·L-1) on the seed germination and re-germination of six typical annuals (Gramineae: Setaria viridis, Chloris virgata and Eragrostis minor; Chenopodiaceae: Bassia dasyphylla, Salsola ruthenica and Corispermum mongolicum) in autumn of current year and next spring, with NaCl and NaHCO3 as neutral sodium salt and alkaline sodium salt. The results showed that NaCl and NaHCO3 significantly affected seed germination of the six species. The inhibition effect of NaHCO3 on seed germination was stronger than NaCl. When the concentration of NaHCO3 reached to 160 mmol·L-1, germination rates of the six species were low. However, when the concentration of NaCl reached to 200 mmol·L-1, the germination rates of the six species were still high. The germination (2.8%-20.0%) and re-germination rates (3.3%-20.0%) in current autumn were much lower than those in next spring, with values of 21.7%-81.6% and 5.0%-41.1%, respectively. In autumn, most of the current year's seeds kept dormancy, but the dormancy weakened in next spring. The salt tolerance of seeds of the six annual species was in the order of C. virgata > S. viridis > S. ruthenica > B. dasyphylla > C. mongolicum > E. minor.