山茱萸花器官发育解剖学的研究

DEVELOPMENTAL ANATOMY OF THE FLOWER IN CORNUS OFFICINALIS

The development of the floral bud in Cornus officinalis can be divi-ded into seven phases, i. e. the early differentiation phase, the floralprimordium projection, the calyx formation, the corolla formation, thestamen formation, the pistil formation and the floral disc formation. The floral bud begins to differentiate in Hangzhou area at the endof April. The floral primordium is formed at the early June, the sepalprimordium on June 10, the petal primordium on June 20, the stamenprimordium on July 10, the pistil primordium on July 20 and the floral disc primordium is formed on September 5. The meiosis of both mega-spore mother cell and microspore mother cell is taken place on Septem-ber 20. By the beginning of November the female gametophyte andmale gametophyte both reach their maturation. The flowers are out inthe following March. The mature pollen grains are 2-celled, 3-colpo-rate. The ovary is generally 1-celled that contain one pendulous,anatropous ovule, which is unitegminous and tenuinucellate. The ma-ture embryo sac consists of seven cells that contain eight nuclei. Byfollowing January 12, three antipodal cells degenerate, two polar nucleifuse into the secondary nucleus, and so that the female gametophyte isonly composed of four cells. Some special structure, e. g. integumen-tary tapetum, hypostase and obturator are formed during the develop-ment of ovule. In addition, the epidermal hair on the scale, the bract,the pedicel and the receptacle is flat T-shaped hair.