Research On Quality Criteria And Dormancy Mechanism Of Phellodendron Amurense Rupr. Seeds

Phellodendron amurense Rupr. is the original plant of traditional Chinese medicine "Guan Huang Bo"(PHELLODENDRI AMURENSIS CORTEX). Up to now, most of Guan Huang Bo still depend on collecting from its wild population. This situation as well as environmental deterioration of habitat resulted in dramatic reduction of the wild resources of P. amurense. Because of its barrier to population self-regeneration and physiological dormancy of seed, it is very difficult to recover its natural resource reserves. As a valuable endangered species, more attention is paid on its artificial cultivation and ex situ conservation. Seeds are important reproductive materials in both population regeneration and artificial cultivation of P. amurense. In this thesis, in order to guarantee the quality of seed source for artificial cultivation so as to promote germination rate, we established the procedure of seed quality testing and standard of seed grading, explored the dormancy mechanism and the measures of dormancy release. We also researched influence of geographical and ecological factors on the seed quality; it helps to understand the dormancy mechanism on a basis of eco-physiological viewpoint.We established seed quality testing methods, including seed sampling, seed purity, weight per1000seeds, seed moisture, seed viability and germination rate. Sampling:free hand halving method. Seed cleaning:water election. Weight per1000seeds:method of hundred seed mass. Seed moisture:dry the seeds at high temperature for3h. Seed Viability:soak the seeds for24h at room temperature, remove the seed coat and endosperm, and then soak the embryo in0.4%TTC for5h at35℃. Germination rate: germinate in paper bed at12℃/24℃. Seed borne fungi:indirectly culture. Seed pest: direct observation. The related data from62seed specimens collected from Heilongjiang, Jilin, Liaoning and Beijing were analyzed by cluster analysis. The seed quality test procedure and the seed quality grading standard were formulated.During the research on dormancy breaking, the germination rate can be significantly improved by cold stratification. Constant cold stratification increases the germination rate from13.50%to89.50%.4℃cold stratification is superior to8℃cold stratification when stratification at constant cold temperature for long time. Fluctuating temperature stratification increases the germination rate from13.50%to90.00%. Fluctuating temperature stratification can shorten the time of stratification, and4℃-8℃fluctuating temperature stratification is superior to8℃-4℃fluctuating temperature stratification. Continuing cold stratification treatment can reduce the germination rate after seed had somewhat germination ability. Seeds soaked with6-BA, KNO3, PEG6000increase the germination rate. Seeds soaked with GA3,6-BA, NAA, KNO3, PEG6000combined with4℃cold stratification for30d can break seed dormancy effectively, and increase germination rate from13.50%to92.00%,97.00%,94.00%,94.50%,83.00%respectively.According to data from our physiological experiment, the seed dormancy type of P amurense is physiological dormancy (PD). There was no significant morphological change during dormancy-breaking process. In dormancy release process, the soluble sugar content first increased from7.96mg/g to11.12mg/g and then reduced to9.65mg/g; the soluble protein content kept stable after increasing from4.11mg/g to5.29mg/g; the activity of LPS increased from118.29U/gprot to489.93U/gprot gradully, and slightly reduced to333.47U/gprot when the dormancy was released; the activity of SDH decreased from3.67U/mgprot to1.26U/mgprot significantly; the activity of PK decreased from7.68U/gprot to4.37U/gprot generally; the activity of G-6-PD kept stable after a continuing increase from1.19U/gprot to2.28U/gprot. The main respiration pathway gradual transform form TCA/EMP to PPP along with dormancy release. During breaking dormancy, the GA3and ZT content increased generally, while decreased at excessive stratification; the ABA content decreased in general; the ratio of GA3to ABA and the ratio of ZT to ABA increased as a whole.During the research on the influence of geographical and ecological factors on seed, percentage of plump seeds was highly significantly positive correlated to flowering period accumulated temperature, annual sunshine hours, significantly positive correlated to growth period accumulated temperature, highly significantly negative correlated to annual precipitation; weight per1000seeds was significantly positive correlated to flowering period accumulated temperature, annual sunshine hours, highly significantly positive correlated to altitude; germination rate was significantly positive correlated to flowering period accumulated temperature, growth period accumulated temperature, annual averaged temperature, annual sunshine hours, growth period days, highly significantly negative correlated to flowering period precipitation, significantly negative correlated to annual precipitation, highly significantly negative correlated to altitude. The results show that the geographical and ecological factors affect not only the seed quality but also the extent of dormancy. Tree age wasn’t significantly correlated to any seed and fruit characters.