Survival and Shoot Formation in Vitro of Pear Winter Buds Cryopreserved in Liquid Nitrogen

Abstract

Vegetative buds of pear (Pyrus serotina Rehder, cv . Senryo) associated with shoot tissue were frozen stepwise to – 40C, immersed in liquid N, and thawed either at 37C in water or at 0C in air. Survival and shoot formation on thawed material was higher when preliminary cooling lasted 12 to 48 h rather than 0.5 to 2 h. The proper thawing temperature depended on the degree of cooling before cryopreservation. A few whole plants were recovered from the cryopreserved buds.