Research On The Tissue Culture Technology Of Dalbergia Sissoo Roxb.

Dalbergia sissoo Roxb.is a hardwood arbor of high economical values,and commonly used for furniture,building material,and shade trees.Due to the low seed setting rate,slow and long growth stage,low propagation coefficient,and constant loss of excellent maternal characters,traditional breeding methods cannot meet the market demand.Tissue culture can overcome the disadvantages of traditional breeding method and obtain a good number of offspring without losing excellent maternal characters.The quality of tissue cultural varieties can also be improved significantly by combining genetic transformation technology.Unfortunately,in a long time,browning and vitrification are two major technical bottlenecks in the development of tissue culture and mass production of D.sissoo.(1)In the present study,budding shoots and adventitious buds of D.sissoo were used as experimental materials to explore the methods of overcoming vitrification and browing.Adventitious buds were the best explants to overcome vitrification.For the adventitious buds,MS culture medium + 0.5 mg/L inositol + 16.5 mg/L NH4NO3 was the best formula to overcome the vitrification.By using this formula,the present study obtained the minimal vitrification rate of 2.145%,the highest seedling height of 1.39 cm,and the highest survival rate of 96.525%;the average earliest germination time was 8.27 d,with a 100%germination rate.(2)30℃ was the best inoculation temperature for the single bud induction of D.sissoo.(3)B5 culture medium was the best for the growth of secondary proliferation culture,with an average proliferation rate of 263.33%.The germination time was 9 d and the average seedling height was 1.40 cm.Under this culture environment,the clumps continued to grow normally without browning after 30 d of inoculation,normal leaf-falling and emerge of new leaves can be observed.(4)For differentiated lateral buds,B5 culture medium + 0.3 mol/L 6-BA + 0.01 mol/L NAA + 0.01 mg/L VC + 0.5 g/L active charcoal was the best formula under 30 ℃ temperature.The proliferation rate of D.sissoo under this condition reached 446.67%.Taken together,B5 culture medium + 0.3 mol/L 6-BA + 0.01 mol/L NAA was the best formula for tissue culture of D.sissoo under 30℃ temperature.The results of the present study showed that the rate of vitrification was not related to the types of explants,but strongly related to the concentration of NH4NO3 and inositol in the culture medium,besides,the induction capacity of adventitious buds was greater than that of axillary buds.Adding 0.1 mg/L Vc and 0.5 mg/L active charcoal to the optimal culture medium can effectively reduce the occuirence of browning.