Cryopreservation of Shoot Tips of Lingonberry in vitro Culture by Droplet-Vitrification
A droplet-vitrification for cryopreservation of lingonberry shoot tips in vitro was studied.Nodal segments with a terminal bud,excising from 30 day-old stock shoots in vitro,were cultured on WPM(woody plant medium)+0.5 mg/L ZT(zeatin zein)+30 g/L sucrose+7 g/L agar(SSM)in the dark at 4 ℃ for 25 d.Shoot tips excised in length of about 2.0 mm were precultured on WPM+0.3 mol/L sucrose+7 g/L agar in the dark at(25±2)℃ for 24 h.Shoot tips precultured were treated with a load-ing solution(WPM+2 mol/L glycerol+1.0 mol/L sucrose)for 30 min at room temperature.Then they were exposed to plant vitrification solution 2(PVS2)at 0 ℃ for 40 min.On aluminum foil strips,each of the shoot tips was transferred into a droplet containing 2.5 μL PVS2 at 0 ℃,followed by a direct immersion in liquid nitrogen(-196 ℃)for 1 h.Foils with shoot tips removed out from liquid nitrogen were immediately put into an unloading solution(WPM+1.2 mol/L sucrose)at room temperature for 20 min.The unloaded shoot tips were cultured on SSM in the dark at(25±2)℃ for 1 d,and then cul-tured at normal light and temperature condition for recovery.The result showed that after 30 days of regeneration cultivation,the average regrowth rate of the four germplasm resources tested was 76%,providing a new approach for the preservation of lingonberry germplasm resources.
lingonberrycryopreservationdroplet-vitrificationshoot tip in vitro