Abstract:

The study aims to clarify the germination protective effect of mucilage of Artemisia ordosica seed on salt stress and to reveal the salt tolerance characteristics of mucilaginous and non-mucilage seeds during the germination stage, providing a basis for artificial sand-fixing afforestation in salinized habitats. Taking mucilaginous and non-mucilage seeds of Artemisia ordosica as test materials, seeds were treated with NaCl solutions at different concentrations (0, 0.2%, 0.4%, 0.6%, 0.8%, and 1.0%), and indicators such as germination rate, germination potential, germination index, and seedling length were measured, the salt tolerance characteristics of mucilaginous and non-mucilage seeds during the germination period were analyzed. The results indicate that: as the concentration of NaCl solution increases, the germination rates of both mucilaginous and non-mucilage seeds of Artemisia ordosica show a decreasing trend. When the NaCl concentration ranged from 0% to 0.6%, the germination rate of mucilaginous seeds was significantly higher than that of non-mucilage seeds (P<0.05). However, at concentrations between 0.8% and 1.0%, the difference between the two was not significant (P>0.05). Under the control treatment, there was no significant difference in the germination index between mucilaginous and non-mucilage seeds (P>0.05). As the salt concentration increased, the germination index gradually decreased. Within the NaCl concentration range of 0% to 0.6%, the germination index of mucilaginous seeds showed significant differences (P<0.05), while no significant differences were observed between concentrations of 0.8% and 1.0% (P>0.05). The germination index of non-mucilage seeds reached highest under the control condition and significantly decreased when the NaCl concentration reached 0.4%. Within the NaCl concentration range of 0% to 0.4%, the germination index of mucilaginous Artemisia ordosica seeds was significantly higher than that of non-mucilage seeds (P<0.05), while no significant difference was observed between the two within the 0.6% to 1.0% concentration range (P>0.05). The plumule length of mucilaginous seeds showed no significant difference between the control group and the 0.2% NaCl treatment (P>0.05), but it was significantly higher than that observed under the 0.4% to 1.0% NaCl treatments (P<0.05). Under low-concentration conditions, the relative of salt damage rate was relatively low, and the relative salt damage rate of mucilaginous seeds was lower than that of non-mucilage seeds. High concentrations of salt had a significant adverse effect on seed germination, with no notable difference in salt damage between mucilaginous and non-mucilage seeds (P>0.05). In summary, under low-concentration NaCl stress conditions (0-0.6%), salt tolerance of mucilaginous seeds is stronger than non-mucilage seeds. Under high-concentration NaCl stress (0.6%-0.8%), there is no significant difference between mucilaginous and non-mucilage seeds. This also indicates that the salt tolerance of Artemisia ordosica seeds during the germination period is relatively weak, while salt tolerance of mucilaginous seeds is slightly stronger than non-mucilage seeds during this stage. This study offers a theoretical foundation for the cultivation and afforestation of Artemisia ordosica in salinized sandy areas and further research may focus on the effects of mixed salt stress and the regulatory mechanisms of mucilage.

Key words: Artemisia ordosica, mucilage, germination rate, salt tolerance, NaCl stress, germination index, relative salt damage rate