为了探究福建青冈种子易萌发、难成苗生长特性的内在调控机制,对其种子吸水率、种子浸提液的生物测定及不同来源种子萌发过程的抗氧化酶活性、内源激素含量变化进行研究。结果表明:福建青冈种皮是阻碍种子吸收水分的重要因素;其种子子叶和胚根的甲醇浸提原液显著抑制白菜种子发芽,低浓度时促进白菜幼苗苗高和根长的生长,说明福建青冈种子中可能存在对种子萌发和幼苗生长有影响的物质;安溪、闽清和建瓯来源福建青冈种子发芽过程中,过氧化物酶(POD)和超氧化物歧化酶(SOD)均能保持较大活性。不同来源种子发芽过程中的丙二醛(MDA)含量变化不同,建瓯、闽清和安溪来源种子分别在发芽第5、9和13天时达最大值。福建青冈萌发过程中,建瓯种子各内源激素含量较安溪和闽清种子早达最大值,安溪来源种子的生长素(IAA)、赤霉素(GA3)和细胞分裂素(CTK)含量始终大于闽清和建瓯来源的种子,而脱落酸(ABA)含量较其他来源种子低。
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.