Studies On The Seed Character And Probulb Formation Of Lycoris Chinesis

Species included in the genus Lycoris Herb. are important ornamental and medical plants. There are about 20 species around the world, of which 15 species are native to China, so our country is rich in wild resources of the genus. Up to now, many scholars have studied on Lycoris, their researches have covered many aspects, including breeding, systematics evolvement, growth, propagation and artificial cultivation and exploitation. However, few reports have been found on the seed characters and formation of the probulb.In this paper, we mainly took Lycoris chinesis to study the seed characters, procedure of the probulb and the bulblet in vitro. Morphology, anatomy and physiology in the procedure of the probulb were also studied. The main contents and results were as follows:(1) Characters of Lycoris chinesis seed were studied. Seeds had much kernel weight and were heavier than water. They also showed much vigour and high water content, but viability was usually lost because of water losing during storage. So we took seeds of Lycoris as a kind of recalcitrant ones. Seeds contained more soluble sugar and starch, but lower fatty acid and protein. There was rich endosperm in the seed. The embryo showed rod shaped and large polarity. Cotyledon, which including haustellum, cotyledon coupling and cotyledonary sheath, was an important part of embryo and played an important role in the formation of the probulb.(2)Probulb formation of Lycoris chinesis was studied. There was a dormancy stage, approximately 30～40 days before seed germination. During the seed germination, the plumule, hypocotyl and radicle were pushed out of the seed-coat because of the elongation growth of the cotyledon, which was different from the way of ordinary plumular axis extension. Its way of seed germination was just like that of onion, so it was belonged to epigaeous pattern. In this paper, according to the morphological and cytological changes, bulb organogenesis was divided into four phases: cotyledon elongation, formation of the first euphylla, elongation of the first euphylla and dormancy stage.(3)During the probulb organogenesis of Lycoris chinesis, metabolism was studied. It showed that content of soluble sugar and protein was both low on earlier stage and high on later stage on the whole. While starch had an opposite tendency, and it existed as crystalline state. During the probulb organogenesis, metabolic pool transferred twice. Each part of the cotyledon played an important role in the utilization of nutriment.(4)Preliminary study was made on the forming process of Lycoris chinesis bulblet. Scales with bulb bases used as explants were cultured on MS-based medium added NAA0.1 mg/L+ 6-BA5.0mg/L. It was a proper way to induce bulblets of Lycoris chinesis. Bulblets arose from the bulb base between two scales. There was white rice-gibbosity in the base of the inner scale about one month later after inoculation, and in the end it became the scale of the bulblet after gradual differentiation. About two months after inoculation, bulblet with one or two young leaves was shaped.