Arsenite-BAL as an Inhibitor of Germination

Imbibition of light-sensitive lettuce seeds in mixed solutions of sodium arsenite and 2,3-dimercaptopropanol (BAL) inhibits light-induced germination more potently than does arsenite alone, particularly at higher temperatures. There is limited reversal of the enhanced inhibition at high BAL/arsenite ratios. The complex is also more inhibitory than arsenite after shorter periods of imbibition. Monothiol compounds do not give the increased inhibition, nor do combinations of BAL with other thiol group reagents. Greater penetrability, possibly into some internal compartment of the cell, is suggested as the cause of the enhancement. Induction of germination by gibberellic acid or low temperature is equally sensitive to arsenite-BAL. The extent of the inhibition of germination of 9 other species by arsenite-BAL is not clearly related to their light-sensitivity.