Effects Of Different Treatments On Seeds Germination And Seedlings Growth Of Apocynum Venetum L.Cv.Songyuan And Preliminary Study On Tissue Culture System

According to statistics,the global saline-alkali land area is about 950 million hectares and the soil salinization has become a hot issue of global concern.Soda alkali-saline land in the western Jilin province,whereas southwest of Songnen Plain,is expanding rapidly due to economic benefits of the people pursue to a temporary over-grazing,blindly reclaims grassland,and without restraint to destroy the ecological environment.Therefore,effective utilization of saline-alkali land to produce economic benefits at the same time,pay attention to the recovery of ecological environment is very important.Apocynum venetum L.Cv.Songyuan is a multipurpose plant can grow in the saline,desert and dry areas,which can bring good ecological,economic and social benefits.In this thesis,the effects of temperature,salt stress,and seeding depth treatments on the seed germination and seedlings growth of Apocynum venetum L.Cv.Songyuan and its tissue culture were studied.Moreover,the suitable Apocynum venetum L.Cv.Songyuan plants growth condition was tested.The research results of this thesis will bring important reference value and significance for guiding the economic development and vegetation restoration of saline-alkali land in the western Jilin Province.The main conclusions of this experiment are as follows:(1)In the condition of below 15 ? and higher 40 ?,Apocynum venetum L.Cv.Songyuan seeds cannot germinate and grow normally.However,the most suitable Apocynum venetum L.Cv.Songyuan seed germination and seedling growth temperature is 25 ?.Compared with 25 ?,in the low temperature of 5 ?,10 ? and 15 ?,there were no significant effects germination rate and seedling growth of bluish dogbane.(2)The effect of salty stress on the germination rate of Apocynum venetum L.Cv.Songyuan seeds were limited,and with the increase of salt stress intensity,the germination rate showed a downward trend.Mixed salt stress was more significant than salt stress alone.Under the same concentration,Na2CO3 treatment had greater inhibition on seed germination than Na Cl treatment.With the increasing concentration of Na Cl,Na2CO3,Na Cl and Na2CO3,the seedling length,young root length and young shoot length were significantly decreased.(3)With the increase of sowing depth,the emergence rate decreased significantly.The sowing depth of about 1 cm is favorable for the plant height,root length,stem length,and leaf number of Apocynum venetum L.Cv.Songyuanseedlings,and similar condition occurred at 0 cm depth.However,near 2 cm sowing depth,and deep sowing(3 cm or less)is not favorable for seedling growth.Therefore,the optimum seeding depth for Apocynum venetum L.Cv.Songyuan seed is 1 cm.(4)The young leaves of Apocynum venetum L.Cv.Songyuan were the best explants for inducing callus.The optimum medium was MS+0.75mg/L 6-BA+0.6 mg/L NAA or MS+1.0 mg/L 6-BA+0.6 mg LNAA,induction rate reached 100%.Meanwhile the most suitable medium for differentiation into shoots was MS+2.0mg/L6-BA+0.2mg/LNAA,the differentiation rate was 12.50%,the optimal rooting medium was 1/2MS+0.7mg/ L NAA and the rooting rate was 88.89%.