The Culture Medium Optimization Of Sweet Potato Meristem Tip And Technology Of Rapid Propagation

Screening of sweet potato stem tip culture medium is critical for the production ofvirus-free seedlings.At present the international general method is that people culture shoot apicalmeristem with1~2leaf primordia. But the size of stem tip and the virus-free rate is negativelycorrelated, and the survival rate positively related. Moreover, quality of plantlets have becameone of the main factors affecting the survival rate oftransplanting,this is due to the fragility ofplantlets. In order to improve the survival rate of the shoot tips and plantlets,this study used thesweet potato stem tips as explants.We hope to find the best medium formula of differenthormone ratio, and have a preliminary study of the osmotic stress and nutrient stress effect onthe resistance of plantlets through the method of orthogonal design, results show:1. We screened the medium for meristem tip culture of sweetpotato under different hormone ratio through the analysis of orthogonal test and range.And we find that the best medium is1mg/L BA+0.5mg/L NAA.Then weverified sweet potato varieties of different genotypes,the results show, seedling rate reaches as high as85%. Through regression analysis, we find that the best medium formula for seedling rate of callus is: MS+1.48mg/L BA+0.5mg/L GA3+1mg/L IAA+0.5mg/L NAA.2.We studied morphological indexes of the plantlets for45days and seedlings that have grown for a month in the greenhouse.The leaf area, stem weight, chlorophyll is higher than that of control group; SOD,POD activity was significantly increased than control undersucrose (30~90g/l) treatment. When the sucrose concentration is75g/l, seedlings has the highest survival rate0f94.7%that was significantly higher than the control.3.Leaf number, root weight was more than that of the control,plant height was lower than thecontrol; CAT activity decreased. The content of soluble protein and MDA increased under thePEG6000treatment. The treatment of PEG6000(0~60g/l) makes the survival rate of Nanshu88lower than that of the contral.4.The leaf number, plant height, root length, root was lower than the control; the activity ofSOD decreased, the activity of POD and CAT increased, the content of MDA decreased underCaCl2(0~9g/l) treatment.When the concentration of CaCl2was3g/l, the seedlings have thehighest survival rate of100%that is higher than that of the control. 5.The plant height, root length, stem weight, leaf area was lower than that of the controlunder mannitol (0~60g/l) treatment, When the concentration of mannitol is30g/l, the survivalrate is the highest, up to96.3%. It is significantly higher than the control.6.The plant height, root length was lower than the control, stem weight, leaf area was higherthan that of the control; the activity of CAT was lower than the control under the reduction of MStreatment.1/2MS teretment has the highest survival rate93%higher than that of the control andit is significantly different from the control.