Drought tolerance during seed germination and young seedling period of Kalidium foliatum under different temperatures

Currently, the regeneration of the population of eremophyte Kalidium foliatum faces obstacles, and seedlings are rarely seen in desert areas. Water and temperature may be two main ecological factors inhibiting self-renewal in arid and desert areas. Therefore, the aim of this study was to explore whether the seed germination characteristics and seedling growth are related to the temperature and drought in the original habitat of K. foliatum. The seedling growth characteristics were studied under different temperatures (20 ℃/5 ℃, 25 ℃/10 ℃, 30 ℃/15 ℃, 35 ℃/20 ℃) and drought stress (PEG 0, 5%, 10%, 15%, 20%, 25%, and 30% PEG). The results showed that different temperatures significantly affected the seed germination and seedling growth of K. foliatum (P < 0.01), and the germination rate and potential of K. foliatum at 30 ℃/15 ℃ were the highest. Different concentrations of PEG-6000 solution had significant effects on seed germination (P < 0.05). At 30 ℃/15 ℃, a low concentration of PEG-6000 solution (5%) slightly promoted the germination rate, potential, and index of K. foliatum seeds, whereas a high concentration ( > 15% PEG-6000) solution inhibited the germination of K. foliatum seeds, and the inhibition increased with increased concentration. Therefore, 30 ℃/15 ℃ can be used as the most suitable temperature for seed germination characteristics and seedling growth period of desert plant K. foliatum. The low temperature in the original habitat in spring is the main factor limiting the self-renewal of the K. foliatum population. Appropriate drought stress is conducive to enhancing the growth of K. foliatum seedlings and promoting their emergence.