Study on Seed Coat and Dormancy Characteristics of Gleditsia sinensis

In order to study the effect of seed coat structure on water absorption of Gleditsia sinensis, explore the relationship between seed coat and seed dormannia, and determine the cause of seed dormannia, the seed coat structure of Gleditsia sinensis was observed by stereopsis and electron microscope after sulfuric acid and hot water treatment, and the structural characteristics and water absorption mechanism of Gleditsia sinensis were investigated by petroleum jelly sealing method and dyeing method. The results showed that the seeds of Gleditsia sinensis were hard, the surface was highly keratinized and covered with wax. The structure of the seed coat changed obviously after hot water or sulfuric acid treatment, the waxy and colloidal substances disappeared, cracks appeared on the seed coat surface and holes appeared in the seed umbilicus. Seal and stain tests showed that the umbilical region was the initial and main water absorbing site of the seeds. After the firmness was removed, many parts of the seed coat could absorb water. The epidermis, palisade layer, bright line, sclerenchyme cell layer of seed coat and the colloidal substance covering the seed umbilicus and seed pore could be the main factors causing the seed firmness of Gleditsia sinensis. Soaking seeds in hot water at 80 ℃ for 10 minutes could break the firmness of seeds. The methanol extract of seed embryo had obvious inhibitory effect on the germination and growth of Brassica rapa var. glabra seedlings. The study showed that the seeds of Gleditsia sinensis could be compound dormancy with both physical and physiological dormancy.