Study On Seed Dormancy Physiology And Culture Technique Of Saposhnikovia Divaticata

Saposhnikovia divaricata is an important medicinal plant,and also a kind of dune-fixing plants.Research about Saposhnikovia divaticata culture became hotspot for the wide resource increasingly dry up.The main question in culture was low germination and sprouting slowly after seeding because of seed dormancy and spring drought in Northeast China.So we began to study coenology charactrristics of Saposhnikovia divaticata,seed dormancy physiology and culture techniques in Northeast China,which was important for good culture.Saposhnikovia divaricata often distributed in the follow communities.Stipa baicalensis, Picea meyeri forest.Carex humilis,Indigofera kirilowii,Quercus liaotungensis forest.Vitex negundo,Themeda japonica tussock.Ephedra sinica,Agropyron cristatum tussock.Carex korshinskyi,Schizonepeta multifida,Stipa baicalensis grassland.Carex duriuscula,Leymus chinense,Stipa grandis grassland.Filifolium sibiricum,Festuca ovina grassland.Leymus chinense,Festuca ovina grassland.Artemisia frigida,Agopyrum cristatum,Festuca ovina grassland.Stipa krylovii,Cleistogenes squarrosa grassland.We collected 36 seed samples of Saposhnikovia divaricata from main producing area, Northeast China and Eastern inner Monglia.Then investigated cleanliness,thousand-grain weight,moisture content,viability and germination percentage of these seed samples.We determined seed quality grading standard of Saposhnikovia divaricata by statistical analysis. Saposhnikovia divaricata seeds were divided into 4 grades.GradeⅠ:germination percentage≥80%,viability≥92%,cleanliness≥93%,thousand-grain weight≥3.7 g,seed moisture content≤9%.GradeⅡ:germination percentage is 60-80%,viability is 82-92%,cleanliness is 84-93%, thousand-grain weight is 3.2-3.7 g,seed moisture content≤9%.GradeⅢ:germination percentage is 40-60%,viability is 72-82%,cleanliness is 75-84%,thousand-grain weight is 2.7-3.2 g,seed moisture content≤9%.GradeⅣ:germination percentage≤40%,viability≤72%, cleanliness≤75%,thousand-grain weight≤2.7g,seed moisture content≥9%.We studied the dormancy cause of Saposhnikovia divaticata seed.Results showed that germination percentage,absorbing water capacity and respiration intensity of seeds without seed capsule were not increased.That is,seed capsule is not the cause for seed dormancy.We observed embryo growth in the storage period by paraffin section,found embryo post-ripening. But it is not the main cause for low germination and sprouting slowly in the field.We also studied the effect of endogenous inhibitory substance on seed germination in situ.Results showed that,endogenous inhibitory substance is the main factor that results in seed dormancy.To develop the suitable seed storage condition which could maintain seed vitality and increase germination percentage,we investigated seed vitality,conductivity,inhibitory activity of extracting solution and germination percentage of Saposhnikovia divaticata during the storage period.Results showed:stored in the sand at 4℃and -20℃were not suit for seed storage of Saposhnikovia divaticata,stored dry seed at room temperature,4℃and -20℃were suit for seed storage in long time,especially stored at 4℃was best,stored in the sand at room temperature was not suit for seed storage in long time.So we suggest store dry seed after harvest,store in the wet sand at room temperature one month before seeding,which could increase germination rate of Saposhnikovia divaticata.To increase seed germination percentage of Saposhnikovia divaticata,we soaked the seeds in GA solutions,rubbed the seeds with sand,soaked the seeds in organic solvent, rinsed the seeds with running water,soaked the seeds in Iixivium of willow branch and poplar branch separately.Results showed:germination percentage of seeds soaked in warm water was 67.5%,germination percentage of seeds rinsed with rushing water was 75%,germination percentage of seeds soaked in warm water and then soaked in lixivium of willow branch was 75%,these three methods increased seed germination percentage of Saposhnikovia divaticata.We extracted and separated endogenous inhibitory substance in Saposhnikovia divaticata seeds by organic solvent.Then gained 7 extractors:aetherⅠ,aetherⅡ,aetherⅢ,aetherⅣ, waterⅡ,waterⅢ,waterⅣ.Results of bioassay showed that,all of water extractors had higher inhibitory activity.Separated and purified water extractors by column chromatography.Based on the result of bioassay,we concentrated the drips separated by column chromatography and analyzed by HPLC-MS.Then consulted references,we concluded the endogenous inhibitory substance likely as follows:linolenic acid,abscisic acid,β-sitosteryl ferulate,oleanolic acid,5-O -methyl a-mminol,cimicifugc acid,β-eudesmol,6-O-acetylarbutin,Chlorogenic Acid.Critical techniques of culture Saposhnikovia divaticata were how to increase sprouting percentage in the field.This paper soaked the seeds in warm water 24 h,then mixed with sand and seeded them in the field,pressed the soil before seeding and after casing soil,which could increased the sprouting percentage to 52%.