Piorino P, Letouze R. Propagation of apple cultivars. Acta Horticulturae, 1983,131:95~99;
[7]
Kevers C, Coumans M and Gaspar T. Physiological and biochemical events leading to vitrification of plants cultured in vitro. Physiol Plant,1986,61:69~748 Pasquletto PL, Zimmerman RH, Fordham I. The influence of cation and gelling agent concentration on vitrification of apple cultivars in vitro. J Amer Soc Hort Sci, 1986,111:976~9809 Poques M, Boxus P. Vitrification review of literature. Acta Horticulturae, 1987,212:156~16610 Standardi A, Micheli M. Control of vitrification in proliteration shoots of Mzs. Acts Horticulturae, 1988, 227:425~427