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% PVSz at room temperature (25℃)for 30 min.After that,they were treated by PVS2 at 0℃ for another 80 min and conserved in liquid nitrogen for 24 h.Next the shoottips 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.