Effects of ethylene on the viability of cryopreserved Dendrobium protocorm-like bodies

  Objective  This paper aims to explore the effects of ethylene on the survival rate of PLBs under cryopreservation to develop ideas for improving the survival rate of PLBs.

  Method  The protocorm-like bodies (PLBs) of Dendrobium nobile ‘Hamana Lake Dream’ were used as materials, exogenous ethylene donor ethephon and ethylene synthesis inhibitor cobalt nitrate were added during the preculture and loading stages of its vitrification cryopreservation, respectively to study the effects of ethylene on cell survival rate, endogenous 1-aminocyclopropane-1-carboxylic acid (ACC) content and ACC oxidase (ACO) activity of the cryopreserved PLBs.

  Result  The addition of exogenous ethylene ethephon can significantly improve the endogenous ACC content, ACO activity and cell survival rate of Dendrobium PLBs after cryopreservation by vitrification. While, the addition of exogenous ethylene inhibitor cobalt nitrate significantly reduced the endogenous ACC content, ACO activity and the cell survival rate of PLBs after cryopreservation by vitrification. In addition, the survival rate of PLBs after cryopreservation was significantly positively correlated with endogenous ACC content and was extremely significantly positively correlated with endogenous ACO activity.

  Conclusion  This study shows that the exogenous ethylene regulator ethephon and cobalt nitrate has a significant effect on the viability of Dendrobium PLBs after vitrification-cryopreservation by regulating endogenous ethylene.