EFFECT OF SILVER-NITRATE ON SUGARCANE CELL-SUSPENSION GROWTH, PROTOPLAST ISOLATION, ETHYLENE PRODUCTION AND SHOOT REGENERATION FROM CELL-SUSPENSION CULTURES

Silver nitrate (AgNO3), an inhibitor of the physiological action of et hylene, reduced cell growth, promoted ethylene production, increased t he yield of protoplasts and reduced shoot regeneration from sugarcane heterogeneous cell suspension cultures. The increase in the rate of pr otoplast isolation from cultures treated with AgNO3 (0 to 59 mu M) cor relate with an increase in endogenous ethylene production by the cells . The addition to the culture medium of chemicals that either inhibite d (aminoethoxyvinylglycine, AVG) or promoted (aminocyclopropane-1-carb oxylic acid, ACC) ethylene biosynthesis did not alter the number of pr otoplasts isolated from these cultures. However, protoplasts were isol ated with AVG in combination with AgNO3, even though ethylene producti on was inhibited. These results suggested that AgNO3 may be having ano ther more direct effect on protoplast release. One such site may be th e cell wall or on cell metabolism conditioning cells to release protop lasts after enzyme treatment.