Abstract:

In order to discuss the seed dormancy characteristics of Protea magnifica, the seed morphology anatomical structure, seed coat ultrastructure and water permeability were observed. The results showed that: ①The seed coat of P. magnifica consisted of three layers, the fence structure of the external seed coat enhancing the impermeability of the seeds, the highly lignified middle seed coat protecting the seeds, the thin inner seed coat covered with a layer of water-impervious wax. ②The acid etching treatment could make the seed coat loose, the seed coat thin, and the seed hole exposed. However, the middle seed coat and inner seed coat etched had already undergone destructive cracking after the 4-hours treatment, which seriously affected the vitality of the embryos. ③The dry seeds and seeds etched for 0.5 h could absorb water quickly in the first 14 h treatment, and nearly saturated after 50 h treatment. Since then, the two water absorption rates fluctuated in a small range until they were fully saturated. ④The seed treated by acid etching did not allow the embryo to absorb water, therefore, the seed coat structure of P. magnifica did not hinder the water absorption of the embryo, but it couldn’t be ruled out the the effect on embryo respiration and the possibility of mechanical resistance to radicle elongation and growth.

Key words: Protea magnifica, structure of seed coat, water permeability, seed dormancy