Vitrified cryopreservation and regeneration of shoot-tips for Citrus medica var.sarcodactylis / 中草药

ABSTRACT

Objective To provide a new approach of preservation for germplasm resources of Citrus medica var.sarcodactylis(CMS).Methods A micrografting test was made on CMS shoot-tips after vitrified cryopreservation,resulting in living shoot-tip.Results First the CMS shoot-tip is inoculated in medium consisting of MS,5%DMSO,and 5%sucrose for 48 h preincubation.Then the shoot-tips were cut off 3—4 mm long and fore-treated by 60%PVS_2 at room temperature(25℃) for 30 min.After that,they were treated by PVS_2 at 0℃for another 80 min and conserved in liquid nitrogen for 24 h.Next the shoot-tips were defrosted by aqueous bath at 40℃and cleaned twice at room temperature(25℃) by MT minimal medium with additive 1.2 mol/L sucrose,10 min once.Finally data collected recorded a higher survival rate of 81.25%by TTC inspectation and a better regeneration rate of 52.94%if the CMS shoot-tips had been grafted on darkly-cultured parental stock,growing,and differentiating normally afterwards.The plantlets detected by polymerase chain reaction(PCR) showed that the pathogens of Huanglong disease had been removed.Conclusion Therefore a conclusion is made that the approach of vitrified cryopreservation may be applied to the preservation of CMS germplasm resources.