几种因素对铁皮石斛原球茎生长和多糖积累的影响

Effects of several factors on protocorm growth and polysaccharide accumulation in suspension cultures of protocorm of D.candidum

通过探讨几种不同因素对铁皮石斛原球茎生长和多糖积累的影响,结果表明,MS、1/2MS、B5、N6和White培养基对原球茎的生长和多糖积累有不同的影响;其中,1/2MS和N6培养基适合原球茎生长和多糖积累。当氮源浓度为30-60mmol/L、NO3^-/NH4^＋分子比为40∶20、30∶30时,有利于原球茎生长和多糖积累。通过二次回归正交组合设计,优化拟合得到激素6-BA和NAA的正交回归模型;寻优定量结果表明,6-BA为1.25mg/L、NAA为0.52mg/L时,原球茎最大干重可达14.68g/L;当6-BA与NAA组合的最佳浓度配比为1.41mg/L、0.36mg/L时,原球茎最高多糖含量为274.2mg/g.DW。在以转速、接种量、pH3因素4水平的L16（43）正交试验中,对原球茎生长影响最大的因子是pH,其次是转速,接种量影响最小;当初始培养液pH为7.0、摇床转速为110r/min、接种量为30g.FW/L时,适合原球茎生长。各因子对原球茎多糖积累的影响程度依次为转速、pH、接种量,当初始培养液pH为5.0、摇床转速为110r/min、接种量为50g.FW/L时,有利于多糖积累。

The effects of several factors on protocorm growth and polysaccharide accumulation were studied in the experiment. The results showed that there were different effects on the growth of protocorms and the accumulation of polysaccharides in five basic media MS, 1/2 MS, B5, N6 and White, and 1/2 MS and N6 were the best media for the growth of protocorms and the accumulation of polysaccharides. The culture medium with total nitro gen concentration of 30-60 mmot/L and the ratio of ammonium to nitrate （either 40/20 or 30/30）was the most beneficial to protocorm growth and polysaccharide accumulation. A regressive model involving 6-BA and NAA was obtained with the quadratic regression orthogonal design, and the maximal dry weight of protocorm of 14.68 g · DW/L was recorded on the medium with 6-BA at 1.25 mg/L and NAA at 0.52 mg/L. When 6-BA and NAA concentrations was 1.41 mg/L and 0.36 mg/L, respectively, the maximum polysaccharides content was 274.2 mg/g · DW. The effects of three factors, including rotation speed, inoculation amount, and initial pH value of the medium for the growth of protocorms were evaluated by L16（43） orthogonal design, which showed the effect pattern as pH〉 rotation speed〉 inoculation amount. Therefore, the optimum pH, rotation speed, inoculation amount for the protocorms growth were 7.0, 110 rpm, 30 g · FW/L, respectively. The accumulation of polysaccharide was noticeably affected by rotation speed, pH, and inoculum amount in significant order. The optimal conditions for polysaccharide accumulation were pH 7.0, 110 rpm of rotation speed and 50 g · FW/L of inoculum.