目的优化MF24真菌诱导子与铁皮石斛原球茎相互作用过程中诱导子的处理方法、加入剂量、加入时间和作用时间等作用条件。方法用不同方法制备的MF24真菌诱导子,以不同的剂量,在原球茎生长的不同时间加入,并继续培养不同时间,观察它们对原球茎生物量和总生物碱含量的影响。结果用MF24的发酵液作为诱导子(方法3)时,收获原球茎的平均干重最高,为0.931 g(每瓶50 mL培养基),与对照相比提高了7.8%。以250 mL·L^-1(诱导子.培养基-1)的剂量(高剂量)加入真菌诱导子时,收获的平均鲜重和干重最高,分别为19.381 g和0.926 g,与低剂量组相比分别提高35.1%和11.8%。将方法3制备的诱导子以高剂量加入原球茎时,获得的总生物碱含量最高(0.048 6%),与对照(0.034 9%)相比提高了39.2%。在原球茎培养的第16周,以高剂量加入方法3制备的诱导子,继续培养6周,收获的平均鲜重和干重最高,分别为26.501 g和1.165 g。这一培养条件下原球茎的总生物碱含量最高(0.068%),与平均值(0.048 8%)相比提高了39.3%。结论MF24真菌诱导子与铁皮石斛原球茎的作用条件为:MF24液体发酵的发酵液作为诱导子,以250 mL·L^-1(诱导子.培养基-1)的剂量,在原球茎培养的第16周加入,继续培养6周后收获。

OBJECTIVE To optimize the interactional conditions of treatments,dosages,supplemented time and handling time between MF24 fungal elicitor and Dendrobium candidum protocorms.METHODS MF24 fungal elicitor was prepared by 4 ways and used with 3 dosages.Distilled water was used as control.Elicitor was added at the different time and then co-cultured with protocorms with different time.The biomass and the content of total alkaloids of protocorms were measured.RESULTS The highest average dry weight(DW) of protocorms was 0.931 g(per 50 mL culture medium) when the fermentation broth of MF24 was used as elicitor(elicitor T3).The DW was increased by 7.8% compared with the control.The highest average fresh weight(FW) and DW of protocorms were 19.381 and 0.926 g at the level of 250 mL elicitor per 1 L culture medium(High dosage) and they were increased by 35.1% and 11.8% respectively compared with the group with Low dosage treatment.Compared with control(0.034 9%),the highest content of total alkaloids of protocorms(0.048 6%) treated with elicitor T3 at high dosage was increased by 39.2%.The highest FW and DW of protocorms were 26.501 and 1.165 g respectively as the elicitor T3 was supplied in high dosage in the 16th week and then handled with protocorms for 6 weeks.By this way,the highest content of total alkaloids of protocorms(0.068 0%) was increased by 39.3% comparing with average value(0.048 8%).CONCLUSION The optimum interactional conditions between MF24 fungal elicitor and D.candidum protocorms was obtained.The fermentation broth of MF24 worked as elicitor at the dosage of 250 mL elicitor per 1 L culture medium in the 16th week and then handling with protocorms for 6 weeks.