Morphological Research Of Flower Bud Differentiation Of Lilium Pumilum

Because Lilium pumilum has extremely cold and strong disease resistance, good quality and graceful style, flower bright and beautiful in color, it is prosperous for garden greening applications, also for a good material of potted plant, and is the important resistance breeding parents of Lilium pumilum. Anatomic observations were made in the terminal bud of Lilium pumilum during flower bud differentiation with the paraffin sections and scanning electron microscope (SEM), to investigate the flower bud development process of Lilium pumilum bulbs by natural winter and artificial low temperature treatment. The major results were as following.1.Morphological characteristics of the stem apex growing point changed from growing cone to reproductive cone in the middle of September in Harbin. In mid-November, the bottom of inflorescence primordium of the1-2foret primordial had completed the differentiation of perianth primordium, and flower bud continued to differentiating in the following spring, then the whole inflorescence finished the differentiation before mid-May. The differentiation of inflorescence lasted8months, and formed4-7flower buds. The flower bud differentiation of Lilium pumilum could be divided into six stages, undifferentiation phase, initial differentiation phase, foret primordial differentiation phase, perianth primordium differentiation phase, stamens primordium and pistil primordium differentiation phase and the whole inflorescence formation phase, respectively.2.The bulbs bud differentiation of Lilium pumilum by artificial low temperature were consistent with one by natural overwintering, the bud of lilium pumilum had begun to differentiate before pilling. At3℃refrigeration, floret primordia continued to grow and differentiate. Refrigerating for8weeks, the lowermost floret primordia was first to differentiate outer perianth primordium. Whenrefrigerated for10weeks, the1-2lowermost floret primordia continued to differentiating inner perianth primordium. Then bulbs were transered at the-2℃refrigerator for16weeks and there was no change in the shoot-tip during the whole frozen process. After open planting, flower bud differentiation continued in the mid-April of the next year, sequentially differentiated stamen primordium and pistil primordium. The whole inflorescence differentiated completely after being planted for3weeks.3.Cylindrical cell nucleus in growing point of cell Lilium pumilum bulbs were the ball spherical or oval when pilled in the autumn, it’s volume accounted for1/3-1/2of total cell volume, nucleolus were1～3pores unequal, close and clearly visible. At present, the cytoplasm contained dense inclusions, more mitochondria, fewer golgi apparatus and it’s secreted not much vesicles. With the refrigeration time extension, nucleus volume increased, the numbers of mitochondriaand and golgi apparatus increased but not obvious at prophase. Refrigerating for8～10weeks, nucleus volume began to increase, mitochondriaand and golgi apparatus increased obvious, and the cells metabolism became more activity.4.Compared with morphology of Lilium pumilum bulbs by natural winter and artificial low temperature treatment after planting exposed in spring, including the height, florescence, visible bud number, flower number, fruit number, flower quality, etc, the result showed that, after planting bulbs by8-10weeks low-temperature treatment, its flowering highest quality, plants upright, flower bright and beautiful in color, the flowers form showing normal had no discoloration and deformation. The florescence time was8-9d,3d late than which by natural winter. The flower numbers were6～7, were no significant difference comparing with natural winter treatment.