Germination Response Of Fraxinus Mandshurica Seeds In Different Released States Of Primary Dormancy To Drying Treatment And Thermal Dormancy Induction

Seed secondary dormancy is related to the physiological state of primary dormancy.Fraxinus mandshurica seeds have primary dormancy characteristics,and will enter secondary dormancy under high temperature conditions.Different combinations of seed germination time will affect the physiological state of primary dormancy release of seeds.The drying treatment of dormancy released seeds will also affect the physiological status of the seeds.However,the relationship between the physiological state of primary dormancy and secondary dormancy of F.mandshurica seeds is unclear.In this dissertation,the mature seeds of F.mandshurica with primary dormancy were used as test materials to study the germination performance of F.mandshurica seeds with different primary dormancy released states at the appropriate temperature and induced thermal dormancy,and whether this germination performance is subject to drying or penetration or exogenous hormone treatment.The related physiological changes of seeds during the induction of thermal dormancy were studied.To investigate the relationship between the physiological state of primary dormancy and secondary dormancy of F mandshurica seeds in order to enrich the physiological regulation mechanism of seed dormancy and germination.The main research conclusions were as follows:(1)The release state of primary dormancy of F.mandshurica seeds had an effect on the induction of secondary dormancy(thermal dormancy).Seeds with shorter lamination times were more likely to enter thermal dormancy.The germination of F.mandshurica seeds with different primary dormancy released states under similar temperature and induced thermal dormancy showed similar rules.The germination ability of seeds with longer low-temperature lamination time(10 weeks)was significantly higher than that of seeds with shorter low-temperature lamination time(8 weeks),and the seed germination law was not affected by drying treatment.(2)PEG osmotic treatment and exogenous hormone GA4+7,GA4+7+ethephon combination soaking treatment can alleviate the induction of thermal dormancy of F.mandshurica seeds with different primary dormancy released states.Ethephon had no significant effect on the thermal dormancy of seeds.PEG osmotic treatment and exogenous hormone GA4+7,GA4+7+ethephon combination soaking treatment had different effects on the induction of thermal dormancy in different F.mandshurica seeds with different dormancy released states.Its influence was affected by the low temperature lamination time.The effect on the seeds with shorter low-temperature lamination time(8 weeks)was greater than that on seeds with longer low-temperature lamination time(10 weeks).(3)The germination of F.mandshurica seeds with different primary dormancy released states at the appropriate temperature or induced thermal dormancy was affected by the drying treatment,and the drying treatment significantly reduced the seed germination ability.If you need to dry the dormancy released seeds for storage,choose a lamination method of warm temperature 12 weeks+ low temperature 10 weeks,and dry to a moisture content of 7%- 10%.(4)F.mandshurica seeds with different dormancy released states during thermal dormancy induction,seed inhibitor activity,embryo sensitivity to GA3,ABA,and endogenous hormones(GA,ETH,CTK,ABA,IAA)content all showed fluctuations.The trend of inhibitor activity was the same,but the sensitivity of embryo and the content of endogenous hormones were different.During the induction of thermal dormancy,the inhibitory activity and endogenous hormone content of F.mandshurica seeds with different primary dormancy released states were significantly different.Its content was affected by the lamination time,especially the low temperature lamination time.When the lamination time was shorter,the inhibitor activity of the seed was higher.The content of hormone in seeds with longer low temperature stratification time(10 weeks)developed in the direction of seed dormancy.But the content of hormone hormones in seeds with shorter low-temperature stratification time(8 weeks)developed in a direction conducive to seed germination.In summary,the release state of primary dormancy of F.mandshurica seeds had an effect on the induction of secondary dormancy(thermal dormancy).In order to effectively prevent the seeds from inducing thermal dormancy,F.mandshurica seeds should try to prolong the low-temperature stratification time when breaking primary dormancy,and adopt the stratification treatment of 12 weeks of warm temperature+10 weeks of low temperature.PEG and exogenous hormones(GA4+7,GA4+7+ethephon)treatment can alleviate the induction of thermal dormancy of F.mandshurica seeds with different primary dormancy released states.Especially for the seeds with shorter low temperature stratification time,these treatments had a better effect on reducing the induction of thermal dormancy.Drying treatment will obviously reduce the germination ability of the dormancy released seeds.If it is necessary to dry the dormancy released seeds for storage,choose the stratification method of warm temperature for 12 weeks+low temperature for 10 weeks.