Effect Of Water Factor On Yield And Qualities Of Dioscorea Nipponica Makino

Dioscorea nipponica Makino. belongs to Dioscoreaceae, which is distributed in Inner Mongolia, Heilongjiang, Jilin, Liaoning, Shanxi, Anhui, Hunan and other provinces in China. The rhizome of it contains much diosgenin which is an important precursor for synthetic production of steroid drugs, and it has high economic value. Modern pharmacology study shows that diosgenin and its derivatives have many kinds of pharmacological activity, such as immune adjustment, reducing blood fat, aging resistance, resistance to oxidation, eliminating sputum, antitumor, AIDS, resisting arteriosclerosis, improving microcirculation and so on. Therefore, it has important economic efficiency and the social significance to D.nipponica research. This paper studied seed germination of D.nipponica and adopted potted plant method to study growing development rule of D.nipponica, and how soil water affects photosynthetic characteristics and production of D.nipponica and diosgenin yield, in order to provide the scientific basis of field production. The major results are as follows:1) Seed germination of D.nipponicaThe temperature was one of the major factors which effected germination of D.nipponica seeds. The suitable temperature of germinating was25℃and the new seeds germination rate was35%more than the old. We proposed some measures to raise the D.nipponica seed-germination percentage:make sure to choose new seeds. If cold sandy stratification is available in production process, it is recommended that treat D.nipponica new seeds with cold sandy stratification (4℃) for60days and then accelerate germination at25℃. If not, treat D.nipponica new seeds with100mg/L GA3for24hours directly before sowing seeds, to promote the seed germinations effectively suitable deep seeding and cover to satisfy it to the dark demand; breed seedlings should at25℃or in the greenhouse, or uses thin film to warm it.2) Effects of water factor on growing development and biomass of D.nipponicaThe effect of different water supply conditions on the development of D.nipponica, but, the biennial a450mm processing D.nipponica growth was optimal index, including roots, stems, leaves index This part studied The relationship of water factors and the yield of rhizome. The yield of underground stem were different with different age, fresh weight of biomass in the second year was higher than that in the first year. The more water or less water was influence on growing development of D.nipponica.3) Effects of water factor on photosynthetic characteristic of D.nipponicaThe photosynthesis transpiration of D.nipponica was studied in this part, to determine its physiological characteristic in differfnt water supply conditions. The results showed that net photosynthetic rate of D.nipponica presented a typical curve, which is the highest in the morning, and then reduce, afternoon change slowly. The diurnal variation of stomatal conductance was certain similar with net photosynthetic. Diurnal changes of sub-stomatal concentration of annual D.nipponica was high in the morning and night, but sub-stomatal concentration of biennial D.nipponica was high in the morning, noon and night. The diurnal variation of transpiration rate presented low in the morning and night, The diurnal variation of water use efficiency presented highest in the morning, and then reduce, afternoon change high. Photosynthetic indicators of annual and biennial D.nipponica were highest in450mm treatment, and the biennial D.nipponica was much better than annual D.nipponica.4) Effects of water factor on qualities of D.nipponicaThe studied water factors to influence diosgenin content of underground stem in plants. It presented the best number about dioscin contents of D.nipponica, that was450mm treatment in on September20, The dioscin contents of annual and biennial D.nipponica increased over the time, and then reduce, The more water or less water was influence on reducing the dioscin contents of D.nipponica. With the increase of underground stem age, the diosgenin content increased. And the diosgenin yield in the second year was higher than that in the first year.