Abstract: In order to explore the mechanisms regulating the seed germination and initial seedling growth of Cyclobalanopsis chungii, the seed water absorption, bioassay of seed methanol extractives, antioxidant enzyme activity and the content of endogenous hormones during seed germination of C. chungii from different provenances were studied. The results showed that the seedcoat was the main factor blocking the water absorption of seeds. The methanol extractives from cotyledon and radical of C. chungii seeds significantly inhibited the germination percentage of Brassica pekinensis seeds. In contrast, they promoted the shoot and root length of B. pekinensis seeds. Thus, it was proposed that there existed some substances in the seeds of C. chungii affecting the seedling growth. The peroxidase and superoxide dismutase of the seeds collected from Anxi, Minqing and Jianou provenances were all able to keep high activities during their germinating, whereas the malondialdehyde content in seeds varied with different provenances. The MDA content in the seeds from Jianou, Minqing, and Anxi provenances reached the maximum on the 5th, 9th and 13th day after germination. During the seed germination process, the contents of endogenous hormones in the seeds of Jianou provenance reached the maximum earlier, compared to that of Anxi and Minqing provenances. The contents of IAA, GA₃ and CTK in the seeds from Anxi were higher than those from Minqing and Jianou, whereas the pattern of ABA content was opposite.

Key words: soil fertility, sandy fluvo-aquic soil, composted sewage sludge, soil active organic nitrogen.