Abstract:

To study the germination mechanism of celery seeds, different reagent combinations (5 g/L NaOH+ 10% PEG, 10% PEG+ 500 mg/L chitosan, 5 g/L NaOH+ 500 mg/L chitosan) and different temperatures (18, 24, 30℃) were used to process the seeds and to explore the germination index, the changes in antioxidant system and endogenous hormone levels in seed germination. The results showed that 30℃ could promote the germination rate, germination potential and germination index of seeds, and accelerate the germination process of seeds. Compared with the control group of distilled water, the germination rate, germination potential and germination index of the combination treatment increased at 18 and 24℃. Under the 18℃, 5 g/L NaOH+ 500 mg/L chitosan treatment, the potential was the highest, and the germination potential reached the maximum under the treatment of 5 g/L NaOH+ 10% PEG at 24℃; there was no significant difference in germination rate, germination potential and germination index between different reagent combinations at 30℃. 18 and 30℃ had a certain degree of stress on seeds, and the activities of SOD and CAT in seeds increased compared with those under 24℃. The content of MDA and proline significantly increased at 18℃. The content of MDA was significantly reduced by the treatment of 5 g/L NaOH+ 10% PEG reagent combination. During the germination, the content of ABA gradually decreased, and the contents of GA₃ and ZA gradually increased in celery seeds. Therefore, the combination of reagents and appropriate high temperature are beneficial to increase the germination rate, germination potential and germination index of celery seeds, and can also improve the germination uniformity. The antioxidant system and hormone levels of celery seeds actively respond to different treatment conditions during the germination process.

Key words: celery, seed germination, antioxidant system, endogenous hormone, reagent combination, temperature