RESTORATION OF THE REGENERATION POTENTIAL OF LONG-TERM CELL-CULTURE IN RICE (ORYZA-SATIVA L) BY SALT PRETREATMENT

Cell suspension, initiated with seed-derived embryogenic callus and maintained for 2 years, produced morphogenically different cell types. No plant was regenerated from fine and friable cells. Low and sporadic regeneration frequency (0.0-0.3 %) was observed in compact cell clusters. Friable cells (20-21 months old) were exposed to salt stress; 0.75 % NaCI mainly inhibited cell growth and induced cells to become compact, whereas 1.5 % NaCI expressed a selective effect of killing all but embryogenic cells of friable cultures. A 3 month pretreatment with 1.5 % NaCl resulted in a reselection of embryogenic cells, restoring the high regeneration capacity of 2-year-old cultures of Oryzella by 60 % and Karolina by 37 % on salt-free medium. NaCl used at a suitable concentration appeared to be an efficient factor for re-establishment of the regeneration capacity of embryogenic calli derived from cell culture in rice. © 1990, Gustav Fischer Verlag, Stuttgart. All rights reserved.