The Dormancy Mechanism And Stratification Technique Of Euscaphis Konishii Seeds

For the seeds of Euscaphis konishii remain deeply dormant for 2 years in their nature enviroment. In this study the seeds of Euscaphis konishii, were selected as the trial material, and through the experiments such as seed paraffin sections of the seeds, water and air permeability of the shell, development of embryo and the biotic measurement of the distilled water and methanol extract of different parts of seeds, meanwhile soaked the seeds in concentrated sulphuric acid first and soaked the seeds in GA3,6-BA, KNO3 in different mass concentration grades and then stratified seeds under different or natural temperatures to find out the methods that could break the dormacy of seeds quickly and effectively; Then discussed the change of content of main storage substances and activity of some key anzymes in order to preliminarily undestand the relationship between process of breaking dormancy and change of material metabolism and the germination physiology of Euscaphis konishii seeds.The main results were shown as follows:The capity of absorbing water showed:the seeds without the shell, abosrbed and swelled quickly, However, the the integrated seeds can still absorb a certain amount ofwater too. In addition, the trial of absoring air showed:the difference of respiratory rate between woraed and integrated seeds was significant during the first 16h, but there were no significicant difference between them after 16 h. So, to a certain extent, there were some water and air permeability obstacles, but they were not the main causes of dormancy of the seeds.On the one hand, the embryo was not mature when seeds fell off the from the tree naturally was one of the main causes of the seed dormancy; On the other hand, the inhibitory activity substances of the seed was the main reason, experiment which extracted from different part of the seed of Euscaphis konishii by using methanol and distilled water indicated that inner inhibitory substances which inhibited the seed generation and the plumule growth of Chinese cabbage exist in the seed kernel and shell of Euscaphis konishii seed, and the inhibitory activity was positively related to the mass concentration of the extracts; The inhibitory activity methanol extracts was stronger than aqueous extracts when they were from the same part of the seeds in the same mass concentration; The extracts from the seed kernel could inhibit Chinese cabbage seed generation and plumule growth at a higher level than that from the shell when they were prepared by the same impregnant and in same mass concentration. Their inhibiting effects decreased gradually during the temperature-accelerated stratification which included 270 days. So, t testified, the seed of Euscaphis konishii has a character of deep dormancy and belongs to morphological physiological dormancy, In other words, The development of embryo is not completely and the strong physiological suppression were the main reasons of the deep dormancy of the Euscaphis konishii seed.The trial of breaking dormancy showed, temperature-accelerated and natural stratification can break the dormancy of the seed of Euscaphis konishii effectively, but it need more time.After nature or comprehensive temperature-accelerated stratification (270 days), Although the gerrmiation rate improved significantly or very significantly, On the whole, the germintion rate was still low. During the different treatments, he treatment of H2SO4 (50%,10 min) firstly,300mg/L GA3 and combined temperature-accelerated stratification had the highest germination rate, But compared with nature stratification, there were no significant difference. As a result, the application directly to the natural stratification is more economic and reasonable.In the course of temperature-accelerated stratification, the activity of amylase and POD increased; the content of souble sugar and protein also increased; both the rough fat and amylum fell followed with the stratification time; Resulted there was high concordance between the change law of the content of innor substance and morphological post-maturation, However, the innor inhabieory activity trial showed:the physiological post-matutration of the seed needs more stratification time.