Seed Germination Behavior Of Two Species From Chenopodiaceae In Southern Gurbantunggut Desert

Ceratoides ewersmanniana and Salsola nitraria were mainly constructive species and significant companion species in Gurbantunggut desert.They both have a strong drought and salt-tolerance capacity,and they were conduct to grassland resources utilization and maintain the ecological balance.In this paper,we studied seed morphology and germination.The main conclusions were as follows:(1)The optimum temperature of Ceratoides ewersmanniana was 20/30 ?.Germination was not affected by Na Cl at concentrations below 0.2 mol/L,and was decreased by Na Cl at higher concentrations,and fell to nearly 0 after 0.8 mol/L.Seeds that were treatment in Na Cl solution for 14 d recovered after being transferred to distilled water and the germination percentage of recovery was higher.Bracts don't have a influence on the germination rate.In 10 months storage,the germination percentage decrease to 24%.(2)Salsola nitraria produces three types of fruits(utricles)that differ markedly in morphological characteristics and germination.Types A fruits are green and spherical and periapts with wings and green utricles;Types B fruits are red and spherical and periapts without wings and green utricles;Types C fruits are yellow and spherical and periapts without wings and green utricles;All of the types of seeds germination in treatment with 12 h photoperiod and 12 h thermo-periods(dark/light)of 5/15??10/20?? 15/25?? 20/30?? 25/35? for 14 d.Germination percentages of type A at all five thermo periods were >92%;Germination percentages of type B at all five thermo periods were <60%;Germination percentages of type C at all five thermo periods were <5.3%.Types B are no-deep physiological dormancy.Types C are deep physiological dormancy.The optimum temperature of Salsola nitraria was 15/25 ?.Germination was not affected by Na Cl at concentrations below 0.2 mol/L and was decreased by Na Cl at higher concentrations,and fell to nearly 0 after 0.4 mol/L.Seeds incubated in Na Cl at concentration of 0.05-4.0 mol/L recovered after being transferred to distilled water.Bracts formed a mechanical barrier to water uptake,and has a significant influence on the final seed germination percentages.