Abstract: This paper studied the effects of different concentration NaCl, Na₂SO₄, and 1:1 NaCl+Na₂SO₄ on the seed germination of Limonium bicolor, and the variations in the seed protein content, amylase activity, and reducing sugar and total soluble sugar contents during the process of seed germination. Under the stress of test salts, the germination potential, germination index and germination rate of L. bicolor seeds decreased obviously, and the inhibition effect was increased with increasing salt concentration. The inhibition effect was in the sequence NaCl>NaCl+Na₂SO₄>Na₂SO₄. The fit salt concentration for L. bicolor seed germination was 1.2% Na₂SO₄, 0.8% NaCl+Na₂SO₄, and 0.5% NaCl, and the half-lethal concentration and fatal concentration of Na₂SO₄, NaCl+Na₂SO₄, and NaCl was 2.1% and 3.5%, 1.4% and 2.4%, and 1.1% and 2.0%, respectively. The regermination test of transferring nongerminated seeds after salttreatment into distilled water showed that salt stress mainly inhibited the decomposition of seed protein and sugar via osmosis effect, and further, delayed or inhibited the seed germination.

Key words: Gynostemma pentaphyllum, Transpiration rate, Stoma conductance, Photon flux density, Net photosynthetic rate