Study On The Germination Characteristics Of Dabidia Involucrata Baill Seed

Davidia involucrata Baill is one of endangered plants in China, with high value both in academic and ornamental horticulture fields. But the natural period of Davidia involucrata Baill is long, germination rate is poor, and emergence is not neat. By the analysis of morphological characteristics, the endogenous inhibitor of biometric and quantitative determination of endogenous hormones change, inclusion and enzymes,ROS systems, revealing the Davidia involucrata Baill seeds germination and physiological and biochemical mechanism from the perspectives of morphology,physiological and biochemical; Gliadin genetic integrity analysis in evaluation of germplasm resources preservation process. The results of the study are as follows:1. Davidia involucrata Baill seeds, cotyledons, hypocotyls process length, fresh weight, measurement results of water content, permeability and biological effects of the extracts showed that: seeds, cotyledons, hypocotyl length, fresh weight and water rates gradually increase in the process of stratification. After eight months,length rate is accelerated, fresh weight and moisture content in the five months increase fastest,Davidia involucrata Baill seeds have physiological after ripening process.Davidia involucrata Baill stone of the fruit have poor permeability, water permeability is not the main cause of seed dormancy. In the process of Davidia involucrata Baill stratification, seeds, cotyledons and hypocotyls leaching has inhibitory effect on Chinese cabbage seeds germination, the extension of this effect as the stratification time gradually, but are not completely relieve inhibition.2. In the same condition and time of stratification, Davidia involucrata Baill storage material and enzyme activity in the seeds, cotyledons and hypocotyls have taken place some changes in the corresponding, but metabolic in the hypocotyls was more activity than the seeds and cotyledons. Soluble sugar, starch, fatty acid, protein were rising trend, the accumulation of the storage matter was the most in the hypocotyls.This shows that during the period of stratification, seeds, cotyledons, provide a good foundation of material and energy for the hypocotyl growth.3. During stratification, the activity of POD and SOD have presented the downward trend,, while the content of MDA remain stable at the begin, finally rise. It shows that at the beginning of the stratification, the seeds activity were strong, but with the extension of stratification time, all kinds of harmful material increase, seeds activity decreased, MDA content increased. This change shows that in the late of stratification,though the nutrients is plentiful, but some of the harmful material produce hindered the process of Davidia involucrata Baill germination, delayed the germination time.4. During the whole process of stratification, endogenous hormone changes were in the direction of beneficial to seed germination. The analysis of single endogenous hormones, GA and IAA content increased gradually, ABA content is on the decline. Endogenous hormone changes in the hypocotyls changes more significant than seeds and cotyledons. Compared with the content of GA, IAA and ABA, found that the ratio of GA/ABA and IAA/ABA showed a trend of rising. Davidia involucrata Baill seed dormancy, endogenous hormones play a role cannot be ignored.5. In the different period of stratification, extract the gliadin of Davidia involucrata Baill cotyledons, hypocotyls, and electrophoresis, found electrophoresis bands in the Davidia involucrata Baill cotyledons, hypocotyls were similar, and a small gap of band number. Both of them have dominant bands. Compared the band change of cotyledons with hypocotyls, both of them changes mainly concentrated in the β area,and hypocotyls band change number is 7, reduced 2, increases 5, it had more changes than cotyledons. Therefore, during the whole period of stratification, Davidia involucrata Baill genetic integrity must be changed. Clustering analysis was carried out on the change of the hypocotyls electrophoresis banding, it can be divided into two categories, buried 0-8 month were a class.At this stage, the gladin bands reduced gradually, and the bands in the 8 month were least. Buried 11-13 month were another class, and buried 8 month was the transition period. In this stage, gladin increased 5bands. Therefore, in the stratification of Davidia involucrata Baill, the bands have increased in the Davidia involucrata Baill can be the turning point into the next phase.