The effects of drought stress on seed germination and seedling physiology of three Limonium species

The plants of the genus Limonium are often used as cut flowers and landscaping materials due to their beautiful flowers and high ornamental value. However, their application in arid and semi-arid regions is relatively limited. To explore the potential of Limonium in these areas, We conducted a study on three wild species in Gansu Province: Limonium gmelinii, Limonium bicolor, and Limonium aureum. By simulating different intensities of drought stress using polyethylene glycol (PEG), we observed the seed germination behavior and the physiological and biochemical responses of seedlings of these three species to drought stress. The results showed that 20 % PEG stress significantly inhibited the germination of seeds from all three species. At the same time, the germination drought tolerance index (GDTI) remained at 0.24 for Limonium aureum under 30 % PEG, higher than the 0.13 for Limonium bicolor, indicating that it possesses strong drought tolerance capabilities even at the seed stage. Multiple physiological indicators at the seedling stage further revealed differences between species. At 30 % PEG treatment, the proline content of Limonium aureum increased by 454.6 % compared to the control, and it exhibited the highest superoxide dismutase (SOD) activity. The principal component analysis results showed that Limonium aureum had the highest comprehensive score (0.487) at 20 % PEG and the strongest overall drought tolerance. The findings of this study provide a theoretical basis for selecting urban landscaping plants in arid and semi-arid regions of northwest China, particularly highlighting the drought resistance and ornamental value of Limonium aureum, making it an ideal material for landscaping in these areas.