Study On Germination Characteristics Of Solanum Nigrum L. Seed And Callus Inductinn

Solanum nigrum L.is a one-to-perennial wild herbaceous dicotyledonous plant of the Solanaceae family Solanum.The whole plant can be used as medicine.Modern pharmacological studies have shown that steroidal alkaloids represented by Solasonine and Solamargine are the main effective ingredients for anti-tumor of Solanum nigrum L.,which can inhibit the proliferation of a variety of tumor cells.In recent years,wild Solanum nigrum L.has been difficult to meet people’s needs in medicine and agriculture.Artificial planting has been carried out.However,the Solanum nigrum L.seeds are small,and the seed germination time is inconsistent,the emergence of seedlings is uneven,and some seeds are dormant.This severely limits the large-scale development of artificial planting of Solanum nigrum L.and reduces its production efficiency.This experiment started from the seeds,hoping to provide a more optimized way for the establishment of Solanum nigrum L.callus and large-scale artificial planting.In this study,the soaking treatment of Solanum nigrum L.seeds by hydroponics,the dynamic changes of the soluble sugar,soluble protein,starch and endogenous hormones indole acetic acid（IAA）,gibberellin（GA₃）,zeatin（ZT）and abscisic acid（ABA）content of seeds at different germination stages were analyzed.On this basis,the quality,clarity,water content and water absorption of the thousand seeds of Solanum nigrum L.seeds were measured,and different exogenous hormones and seed soaking temperatures were used to observe the germination vigor,germination rate,germination index,vigor index of the seeds and the root length and plant height of the seedlings.Solanum nigrum L.seeds and seedlings under salt stress are treated with different mass concentrations of exogenous 5-aminolevulinic acid（ALA）,measure the germination potential,germination rate,vigor index and germination index of Solanum nigrum L.seeds,and the photosynthetic pigment content,malondialdehyde（MDA）content,plasma membrane permeability,soluble protein content,free proline content,superoxide dismutase（SOD）,peroxidase（POD）,Catalase（CAT）activity was measured.In this study,tissue culture technology was used to screen the best explants and the most suitable medium types for tissue culture of Solanum nigrum L.,and use response surfaces to optimize the culture medium for Solanum nigrum L.callus induction.The content of soluble protein,malondialdehyde（MDA）,Solasonine and Solamargine at different stages of callus proliferation was determined,and the cell viability,superoxide dismutase（SOD）,peroxidase（POD）,enzyme activity of polyphenol oxidase（PPO）,and draw growth curve.Achieve the following research results:1、With the advancement of the germination process,the soluble sugar content first increased and then decreased;the soluble protein content decreased-increased-decreased;the starch content increased-decreased-increased;the IAA content showed a gradual increase trend;GA₃ showed a decreasing-increasing-decreasing trend;ZT showed a trend of first increasing and then decreasing;ABA content gradually decreased with the germination of seeds.IAA has a significant negative correlation with starch,ABA has a very significant positive correlation with starch,and IAA has a very significant negative correlation with ABA.The ratios of IAA/ABA,GA₃/ABA,and ZT/ABA showed increasing trends in varying degrees with the increase of the germination time of Solanum nigrum L.seeds.2、Solanum nigrum L.seed purity is about 81.26%,the mass of thousand seeds is（2.94±0.12）g,the water content is about 7.85%,and the water absorption rate is up to 87.15%,which is 1.87times the mass of natural air-dried seeds.Soaking the seeds with a GA₃ solution with a mass concentration of 150-200 mg/L for 24 hours and 42℃water bath for 2 hours has the best treatment effect,which can effectively improve the germination rate and seedling rate of Solanum nigrum L..3、Under salt stress,the germination index of Solanum nigrum L.seeds was inhibited.After exogenous ALA treatment,the germination potential,germination rate,vigor index and germination index of seeds were significantly improved;after ALA treatment of Solanum nigrum L.seedlings,the contents of chlorophyll a,chlorophyll b,carotenoids,and total chlorophyll were significantly increased;the plasma membrane permeability and leaf MDA content were reduced;the soluble protein and free proline content were increased;the activities of SOD,POD and CAT have been significantly improved.Exogenous ALA improves the germination index of Solanum nigrum L.seeds,increases the photosynthetic pigment,osmotic adjustment substance content and antioxidant enzyme activity of seedling leaves,reduces the damage of cell plasma membrane,effectively slows the damage of Solanum nigrum L.seeds and seedlings caused by Na Cl stress,and improves its Salt resistance.4、Solanum nigrum L.stem is the best explant,and the most suitable medium for inducing callus is MS+NAA1.43mg/L+6-BA2.15mg/L+KT2.48mg/L,the most suitable proliferation medium is MS+6-BA1.0mg/L+NAA0.2mg/L,the fresh weight growth of callus showed an"S"-shaped trend,and the cell viability reached the highest peak at 20d.The soluble protein content and POD activity both increased first and then decreased.SOD activity appeared two at 20d and 30d.At the peak,the MDA content first decreased and then increased.The PPO activity decreased in the later period of culture,which may be related to the browning of callus.The change trend of Solasonine and Solamargine content was consistent,reaching the highest peak on the 30th day.The callus growth period of Solanum nigrum L.is 25d,and it is also the most suitable harvest period for callus fresh weight.After 25d,browning will appear in varying degrees.