Effects Of Low Temperature Storage Conditions On The Vigor And Related Metabolite Components Of Hemp Seed

At present,in terms of seed preservation,cryopreservation technology is an ideal preservation method for long-term preservation of plant germplasm.The systematic research on cryopreservation of hemp seeds is still blank at home and abroad.Therefore,the purpose of this experiment is to explore the physiology and metabolomics regulation mode of hemp seeds under cryopreservation conditions,the seedling emergence rate,plant height,chlorophyll content and related soil nutrient content of hemp seedlings in the research and improvement of seed cryopreservation technology.In this paper,the molecular mechanism and important regulatory substances of seed low temperature tolerance regulation are revealed,and technical and theoretical references are provided for effectively prolonging the lifespan of seeds and maintaining the vigor of seeds.In this study,a total of controls CK1(stored at room temperature for 1a),CK2(stored at room temperature for 2a),A(stored at 4℃ for 1a),B(stored at 4℃ for2a),C(stored at-20℃ for 1a),D(stored at-20℃ for 2a)6 treatments.The germination rate,antioxidant enzyme activity,malondialdehyde content,sugar metabolism-related enzyme indexes,seedling emergence rate,plant height,chlorophyll content were measured at different treatment hemp seed stages,and the non-targeted metabolism was carried out.Omics to explore the molecular mechanism and important regulatory substances of seed low temperature tolerance regulation.1.The low temperature storage conditions improved the germination rate,germination potential and germination index of hemp seeds.The germination index of hemp seeds stored at-20℃ for 1a or 2a showed an upward trend.2.Cryopreservation conditions enhanced the antioxidative enzyme activity of hemp seeds.Compared with CK1,catalase(CAT),superoxide dismutase(SOD),and peroxidase(POD)C treatment increased by 34.74%,199.90%,and 473.84%,respectively.Stored at-20℃,the contents of 1a malondialdehyde(MDA)and proline(PRO)decreased by 44.94% and 32.13%compared with normal temperature.3.Under different cryopreservation conditions of hemp seeds,C treatment increased by133.32% compared with CK1 sucrose synthase(synthesis direction: SS-II)activity,sucrose phosphate synthase(SPS)activity,sucrose content,and glucose content,respectively 427.03%,65.12%,72.66%.The activity of sucrose synthase(decomposition direction: SS-Ⅰ)decreased by 83.07%.4.Using non-targeted metabolomics,it was found that the sucrose content of treatment A was significantly down-regulated,which was consistent with the detection results of physiological indicators.The major metabolic pathways involved in key metabolites are phenylalanine,tyrosine and tryptophan biosynthesis,tryptophan metabolism,phenylalanine metabolism,isoquinoline alkaloid biosynthesis,phenylpropane biosynthesis,Metabolism of glyoxylic and dicarboxylic acids.In addition,when hemp seeds were stored in 1a or 2a at low temperature,the changes of differential metabolites were relatively stable at-20℃.5.The emergence rate,seedling plant height and chlorophyll content of hemp seeds stored at-20℃ for 1a were higher than those stored at room temperature.To sum up,the germination rate,seedling emergence rate,plant height and chlorophyll content of hemp seeds under low temperature storage conditions were improved compared with room temperature.And by increasing the activity of antioxidant enzymes,reducing the content of malondialdehyde and proline,and promoting the metabolism of sucrose,the seed vigor is maintained,so the low temperature condition is conducive to the preservation of hemp seeds,and the mechanism of preservation of 1a hemp at-20℃ maintains a higher seed vigor.It can effectively reduce the seeding rate and cost when sowing.