Abstract:

In order to alleviate the negative impact of salt stress on the germination of Cosmos bipinnata seeds and improve their salt tolerance, and to provide technical support for the cultivation of C. bipinnata on saline-alkali land, this study used the seeds of C. bipinnata as research materials to examine the effects of seed priming with different concentrations of exogenous substances (CaCl₂, SA and SNP) on the germination of C. bipinnata seeds under critical NaCl stress. The results showed that the germination rate of the control group was 97.78%, while that of C. bipinnata seeds under 175 mmol/L NaCl was 42.22%, which decreased by 56.82% compared to the control group. Therefore, the critical NaCl stress concentration was 175 mmol/L. After priming with 0.2 mmol/L SA, 0.3 mmol/L CaCl₂, or 0.25 mmol/L SNP, the germination rates of C. bipinnata seeds under 175 mmol/L NaCl were 72.22%, 71.11%, and 64.44%, respectively. All of these could effectively alleviate the inhibitory effect of 175 mmol/L NaCl on germination. Therefore, it can be seen that seed priming with appropriate concentrations of CaCl₂, SNP, and SA can alleviate salt stress on the germination of C. bipinnata seeds.

Key words: Cosmos bipinnata, salt stress, calcium chloride, salicylic acid, sodium nitroprusside