Study On Polyploidy Induction Of Lily By Somatic Tissue And Pollen

Oriental hybrids and Longiflorum hybrids are very important in lily cut flowers on the world market. They act as ornamental and commercial function with high economical value. So choosing two of them, Lilium siberia and Lilium Longiflorum as materials, we studied on the somatic tissue and pollen chromosome doubling through tissue culture and buds treatment. In this way, we can found the technical and material resources ground for creating artifitial lily triploid.Founding the tissue culture system is one of the preconditions for the induction of lily somatic tissue polyploids. The result of tissue culture shows: the most appropriate medium for bulb scale germination of L.siberia is MS + sucrose 4% + BA 1.0mg/L + NAA 0.5mg/L medium. The concentration and mixture ratio of hormone are two of the important factors in bud inducing. The concentration of sucrose is the most important factor in bulblets growth, and the most appropriate medium for rooting induction and sound seedling of bulblets is MS + sucrose 8% + NAA 0.3mg/L.Knowing the diploid chromosome number and karyrotype of L.siberia is another precondition for its somatic tissue polyploids induction. Through the observation of mitosis course of L.siberia, we get the conclusion that the diploidy chromosome number of L.siberia is 2n=2x=24, its karyotype formula is 2n=2x=24=4m + 2t +14st + 4sm(SAT), belonging to 3B type. Then, We use physical and chemical methods to induce L.siberia somatic tissue polyploids, and in the end we find: the effect of physical treatment is not obvious because we just get some phynotype variation bulblets but no polyploidy cells after the evaluation of chromosome number. Polyploidy induction by chemical methods is carried out with colchicine by tow ways, that is cultured on the medium with colchicine and marinating in the solution of colchicine. By the way of cultured on the medium with colchicine, we only get 2 mixoploids, their cells some are diploids and others are tetraploids, and we have not find pure tetraploids. The best concentration of colchicine are 0.02% and 0.05%, and the best time of its treatment is 48h by marinating way. After these treatments, we get 4 tetrapliods in all, the rates of tetraploidy cells are all above 90% in their 18 offsprings. After the cytological comparation of diploids and tetrasploids leaves, we find the difference of stomatal density and size both are significant.In the study of 2n pollen induction of L.Longiflorum, we first studied on the meiosis course of its pollen mother cells, and the result shows: There is relationship between flower buds length and PMC developmental periods. When the flower bud length is 1.0cm～2.5cm, the PMC is of the vigorous development. PMCs are in the same stage of the same anther. The chromosomes of PMC duplicate once and then go through dividing twice. In the end, one PMC will become four pollens. Because there is no cell plate forming in the telophaseI, it belongs to successive cytokinesis. The best time for 2n pollen induction is when the length of flower buds is 0.5～2.4cm. On the ground of this, we treated the L.Longiflorum flower buds by two methods to induce 2n pollens: injection with colchicine solution and wraping with pledget sinked by colchicine solution. The former method is more suitable to lily flower buds than the latter one because lily flower buds are too sensitive to bear the high physical and chemical hurt of wraping way. After injection 0.1% colchicine solution three times into lily flower buds, we get some much bigger and deeper color pollens, they are regarded as 2n pollens.