| Fourteen Populations or strains of Dioscorea zingiberensis C.H.Wight from the Wudang Mountain Fang county, Yunxi and Songzi of Hubei, Shiquan of Shanxi and Anhua of Hunan were cultivated in experimentation field of Huazhong Agriculture University and used as materials in the research. Comprehensive research of phonological phase, morphological physiological characteristics not only offered theory for directional breeding high yield and quality cultivation but also accumulated information for basic research. The main results were shown as follows:1. Dioscorea zingiberensis C.H.Wight cultivated in Wuhan area germinated in the first ten days of March,rapidly growed from the first ten days of May to the middle ten days of July, blossomed and seeded from the middle ten days of May to October. Overground segment died away from the beginning of November to the last ten-day of December into dormancy stage. The phonological phase of Dioscorea zingiberensis was 230-280 days, showing difference of 14 populations. Therefore, filtrating resource should not be blindness.2. Studies on the anatomy of rhizome root tip of adventitious root and stem in Dioscorea zingiberensis C.H.Wight were done with the paraffin method. The biennial rhizome of D. zingiberensis was composed of three pans: the periderm, the ground tissue and the vascular bundle. The periderm was the secondary protective tissue of the rhizome, and is composed of pellem, pellogen and phelloderm; the ground tissue was composed of parenchyma cells mature vascular boundle, which belonged to closed vascular boundle with no intrafascicular cambium , was surrounded by vascular bundle sheath, which was composed of mechanical tissue cells whose cell wall was thickened. The root tip of adventitious root included four parts : root cap meristem zone, elongation zone and root-hair zone. Structure of stem was similar with that of monocotyledon which was composed of three pans: coat ground tissue and closed vascular bundle with no intrafascicular cambium.3. Difference of color and diameter from 1.7 to 3.7 centimeter of stems in 14 populations of Dioscorea zingiberensis was obvious; variance of leaves wastremendous ,but in all in wide leaves had relatively high contents of diosgenin. In addition, difference of seeds figuration was much little, and weight of one thousand seeds which was from 7.508g to 20.519g had bigger differentia.4. Difference of chlorophyll content in 14 populations was unconspicuous. Chlorophyll content (chlorophyll a b or both a and b) and photosynthetic rate showed significantly positive correlation in different populations, correlative coefficient was 0.651 0.634 and 0.823. In addition, correlative coefficient of photosynthetic rate and rhizomes yield was 0.875,showing significantly positive correlation.5. In the same condition, differentia of physiological indexes in different populations were little. Mean value of protein content and soluble sugar content were respectively 0.12% and 0.17%, mean activity of POD PPO and SOD were 1037.14u/g min, 1610.00 u/g min and 246.11u/g. These indicated that Dioscorea zingiberensis had formidable adapting capability and less requirement for survival surroundings.6. Fertility of mature pollens were detected by I2-KI dyeing, showing fertility of different populations as much as mean value which was 48.09%.7. Research of the relation between water content and diosgenin in rhizomes showed that diosgenin and water content took on significantly positive correlation whose correlative coefficient was 0.878; Diosgenin content of male strains were higher than that of female strains. Therefore, if cutting out inflorescences of female flowers and controlling seeds ,rhizomes would obtain full nutrition and have more diosgenin.8. DNA of 14 populations was amplified by 12 random primers from 40 random primers, the polymorphic bands of RAPD were counted. And the results of types were analyzed by POPGENE1.31 software. The results indicated that a total of 73 bands was obtained, 64 of total bands(87.67%) was polymorphic and that there were apparent and abundant genetic variations in Dioscorea zingiberensis The formation and accumulation of diosgenin could be affected substantially by the genetic basis of Dioscorea zingiberensis ,... |
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