Study On Characteristics Of Flowering And Pollination On Biology Of Glycyrriza Uralensis Fisch

Glycyrriza Uralensis Fisch is an important medicinal plants since ancient times, and also plays a very significant role in many industries such as food, cosmetics, tobacco, light industry, petroleum and fire system. Meanwhile Licorice is the important sand-fixation plant in western areas of China. Recently, with the increasing demand of Licorice, the wild Licorice has been over collected and endangered, while the artificial cultivation has been the focal topics in the research of Licorice. To select high quality strain of Licorice is the only option to enlarge the planting areas of the artificial cultivation and alleviate the crisis of the wild Licorice.The pollination method of plants can directly affects genetic characters, breeding strategy,seed production methods and cultivated management technology. Plant embryology is the fundamental to study the genetics and breeding of plants. Considering lack of a consistent understanding of the technique of artificial-pollination of the Licorice, which was unable to guide the breeding practices, this study used the wild Licorice for the experimental materials from Keshiketeng county, Inner Mongol Autonomous Region and Fuhai in Xinjiang, studied the biological pollination of the Licorice by the observation of floral organs' morphology, the experiment of field pollination, the experiment of pollen tube's germination labeled with fluorescent markers, the study of the development of male and female gametophyte around the pollination as well as the molecular markers of AFLP.1. The morphological characteristics of the Licorice's pollen tube suggests that the Licorice has the character of Cross-pollination: The little flowers of Licorice are larger, the variation ranges from 10 to 20mm,and the corolla is bright purple or pale purple firstly blooming out of calyx. Pollen grains are stereo and in near spherical shape, and the surface has granular apophysises or not; the space distance between stigma and anther is 1-1.5mm, and the pollen can hardly reach the stigma; while the Licorice has vertical inflorescence, and the sequence of bloom is from bottom to top. Thus, from the characteristics of the external morphology of the Licorice, it has the character of cross-pollination.2. The experiment of field pollination preliminary judge that the Licorice is a plant of Cross-pollination:By experimenting on the Licorice from Inner Mongolia and Xinjiang with the single flower covered, single plant's inflorescence covered, same inflorescence be cross pollination artificially, monoecious be pollinated by different inflorescence, cross pollination among the individuals, the result was that the pod rate of Licorice in natural condition was only 10%..The treatment with single flower covered has no pod, and the pod rate of single plant's inflorescence covered was only 1.6%,but the pod rate of artificial pollination improved significantly, the pod rate of same inflorescence pollinated by different flowers was 14%,same plant pollinated by different flowers was 25%,while different plants pollinated by different flowers was 58%. It suggests that Licorice is a Cross-pollination plant, and artificial pollination can improve the self-fruitful rates of Licorice. Also, the pollinators of Licorice are bees by tracing observation of camera.3. The molecular markers of AFLP determined the genes of Licorice were heterozygous:Choosing five parent each of 50 plants, respectively from Hami, Alar, Hotan, Bachu and Yarkand, and using screened 9 primers to make analysis of AFLP for total DNA, discovering that the percent of difference bands from the same parent's different offspring's plants is 19.32%.It suggested that the genotypes of Licorice were heterozygous but not exactly homozygote.4. The germination rates and the length of elongation of Licorice's pollen tubes under different pollination methods are not alike. it suggests that after the pollination, the pollen disrupting rate was up to 15-20%, the germination rate of pollen tube after pollination can be 30%, but the length of elongation of pollen tube was short that unable to reach the ovules to complete the double fertilization; suggesting that the short germination of pollen tube after pollination is one of the reasons for self-incompatibility of Licorice. While pollen tubes' germination rate after the artificial cross pollination between different plants was up to above 90%, and germinated quicker, so it can reach the ovules quickly to complete the fertilization and develop vigorous seeds. This test supports the conclusion that Licorice is a cross pollination plant.5. The pollen viability of the licorice is the highest on the day of anther dehiscence, the best pollination period of stigma is the second day after flowering. The samples were collected periodically around the anther dehiscence, to undergo TTC staining to determine the pollen viability. The result shows that, on the day of anther dehiscence, pollen viability is up to 94%, the 2nd and the 4th after the anther dehiscence, the pollen viability fell slightly but still remain above 90%,then decreased swiftly, to the 16th,pollen would be dead and the vigor was all lost. Stigma energy of Licorice was related to the development time of flowers, and the lifespan of stigma is 3d,the viability of stigma was the highest in the 2nd,so was the best pollination time.6. The characteristic of embryonic development around pollination showed that after fertilization the low number of normally developed ovules was the major reason of the low fruit-setting ratio. The little flowers in many different development stages as experiment material, identifying that microspore of the anther undergo meiosis was tetrad, and ovules were campylotropous, the two polar nuclei would come nearer or fused then fuse with sperm cell when fertilizing. But in large number of sections, the broken pollen and the normal developed ovules decreased, would be one of the reason for low fruit-setting ratio,Thus to carry out the research about the process of the sexual reproduction of Licorice will be helpful to work on the genetic and breeding of Licorice and provide relevant knowledge in basic theories study of Reproductive Biology, and also provide the theory basis of Licorice's breeding work.