The Research Of Dioscorea Dormancy

Yam (Dioscorea opposita Thunb.),also known as yam, commonly known as yam, is a winding vine of the genus Dioscorea. Dioscoreaceae with high medicinal value and nutritional value is one of the famous four pregnant drug. In this study,145yam germplasm materials from the origin of the five provinces of Hainan, Yunnan, Guangxi, Guangdong, Fujian were examined, and their dormancy traits were observed and recorded; yam number221,230,128, big potato number6, and gross potato number23were chosen as the experimental subjects to explore the variation regularity of yam dormancy and tuber physiological indexes of different types of yam under different processing conditions and processing methods.The test results show that:1. Through the observation of the Yam dormancy to classify the yams into four groups based on the various length of their dormancy. Group one:dormancy>110d, including:Nos.8and9,64species in total; group two:100d<dormancy≤110d, including Nos:1and3,43species in total; group three:90d<dormancy≤100d, including:Nos.4and7,25species in total; group four:80d<dormancy≤90d, including:Nos.2and5,30species in total.2.Using plant hormones with different concentrations and types, and the soaking coat method to dispose the yam tubers in order to observe the impact on their dormancy features. The results reveal that:soaking with gibberellin solution with low concentration can shorten the dormancy of yam tuber which contains7d and60d (about10to15d), while soaking with the one with high concentraion can significantly extend the dormancy of the yam (maximum:37d).The impact of the paclobutrazol solution with different concentration on the dormancy of yam tuber is slight, while the soaking coat method can massively shorten the dormancy of the yum (about20d)3.According to the examination of the plant physiological indicators of the yam tuber, it is revealed that:the yam tuber will enter into deep hibernation period during the early days of the storage period. Physiological indicators during this period tend to be stable. In different processing procedure, during the late period of the dormancy of the yam tuber, namely the period about to end the dormancy (10d before germination), the water-soluble protein will be increased dramatically. It is a slow transition period before the end of the dormancy when the yam tuber does not germinate. During this period, method could be used to extend or shorten the dormancy period of the yam. Using gibberellin solution with high concentration on the yam tuber, polyphenol oxidase will increase first and then decrease sharply, while the activities of amylase will increase. Since amylum degradates quick, it will cause the accumulation of the product and restrain the activity of the enzyme which then make the yam tuber enter into its second round dormancy. Soaking coat method can accelerate the respiration of the yam tuber and therefore enhance the activity of the polyphenol oxidase related to the respiration and shorten the dormancy of the yam tuber.4. Compare the characteristics of different types of yam dormancy and the yam morphological cluster analysis and ISSR cluster analysis, The yam tuber dormancy characteristics and ISSR markers were not in good agreement,but can be consistent with the morphological markers, cluster analysis of SSR markers on the contrary.