Studies On Characteristics Of Dioscorea Nipponica Makino From Different Areas In Changbai Mountain

Dioscorea nipponica Makino is a plant of the family Dioscoreaceae,which is distributed in Inner Mongolia,Heilonjiang,Jilin,Liaoning and other provinces in China,one of the main sources is diosgenin.The plant is not only a main resource to medicines for cardiovascular diseases,but also is a widely used raw material for the production of steroid and contraceptive. Because the seeds source is scarce,blind introduction,and did not consider plants compatible question,the production efficency is not good.In order to improve and optimizes Dioscorea nipponica introduction cultural technique,we collected samples from four east mountainous areas(Antu,Chingyu,Tonghua in Jinlin province and Qingyuan County in Liaoning province) of Changbai Mountain and introduced them to Changchun.We investigated their characteristics of seed germination condition,the photosynthesis transpiration as well as the heredity stability. This research is advantageous to the breeding worker understood fully the biology characteristic and the genetic background of the breeding material,may provide the scientific basis for the Dioscorea nipponica introduction.This research is divided three parts:the first part introduces a fine variety the different local dioscorea nipponica,to observe its growth developmental mechanism and the seed germinates biological characteristics;the second part is using random amplified polymorphic DNA mark (RAPD) technology to examine four local Dioscorea nipponica genetic diversity;the photosynthesis transpiration of Dioscorea nipponica is studied in the third part,to determines its physiological characteristic.The results are as follows:Firstly,we clearly reported Dioscorea nipponica's biology characteristic and many factors that influence seed germinating.Regarding the vegetative reproduction,the growth rule of dioscorea nipponica introduced to Changchun is similar with other wild and cultivation species. The growth is mainly divided into six stages,namely the seedling period,the nutrition vegetal period,pregnant the flower bud florescence,the fruit time,the rhizome vegetal period and wither period.After the introduction,four local Dioscorea nipponica growth durations are basic consistent,close 150 days.As to sexual reproduction,it has not blossomed the fruit phenomenon in the first year growth,namely does not have the reproduction stage.Moreover,growth duration period is nearly a half month longer than vegetative duration,has displayed to bud time to be ahead of time,withers the time to postpone.We have studied the seed germinating characteristic.As a result of this,we proposed some measures to raise the Dioscorea nipponica seed-germination percentage:make sure to choose new seeds;use the ordinary fungus(for example carbendazim and so on) to soak before sowing seeds;After the clean,use 100μg/mL gibberelin immersion,to promotes the seed germination effectively;suitable deep seeding and cover to satisfy it to the dark demand;breed seedlings should in 20-25℃or in the greenhouse, or uses thin film to warm it.Secondly,we filtered 5 clearly and high polymorphism primers from 20 random primers. We carried on the cluster analysis to four area's Dioscorea nipponica DNA fingerprint and get DNA molecular dendrogram.The study results showed that Antu's Dioscorea nipponica genetic distance is greater than three others,which manifested the kin relationship between them is far. The Dioscorea nipponica genetic distance in Qinyuan and Jingyu is close and their kin relationship is also near.The results showed that net photosynthetic rate of Dioscorea nipponica Makino presented a typical one-peak curve,which the peaks(4.96μmol·m^-2·s^-1) appearing at 12:00.There didn't appear a phenomenon of "photosynthesis midday depression".The diurnal variation of transpiration rate presented a one-peak curve in leave of Dioscorea nipponica Makino,and the peak of transpiration rate measured at 12:00 was 5.73 mmol·m^-2·s^-1;The diurnal variation of stomatal conductance presented a one-peak curve in the leaves of Dioscorea nipponica Makino, and the peak of stomatal conductance measured at 12:00 was 64.28 mmol·m^-2·s^-1.It didn't appear the situation of stomatal closure because of excessively intensity of illumination;The diurnal variation of water use efficiency presented a one-peak curve,and the peak of water use efficiency was measured at 12:00,then to drop out;The positive relationship between net photosynthetic rates and stomatal cuductance of Dioscorea nipponica Makino was extremely significant(P＜0.01),the positive relationship between net photosythetic rate and transpiration rate was extremly significant(P＜0.01).The low temperature was the main environmental factor which influenced the Pn of Dioscorea nipponica Makino.