A comparison was made to determine the effects of bracteoles on the germination response of a salt marsh annual Atriplex prostrata and a salt desert perennial Atriplex griffithii. Attached bractoles did not inhibit the germination of A. prostrata but completely inhibited the germination of A. griffithii seeds. The presence of detached bracteoles of A. griffithii in petri dishes with seeds also inhibited germination. Water soluble extracts from bracteoles of both species indicated that they contained up to 132 g/kg total salts in A. griffithii and 87 g/kg total salts in A. prostrata. The water potential of dissolved substances in bracteoles extracts was 15.2 0.17 MPa for A. griffithii and -12.1 0.74 for A. prostrata. The ash content of bracteoles on a dry weight basis was 28.7 0.4% for A. prostrata and 30.0 0.3% for A. griffithii. Soluble salts are inhibitory to the germination of both species and the presence of relatively high concentrations of total salts in bracteoles may explain the reduced germination in A. griffithii. Germination of seeds of the perennial A. griffithii may also be mechanically inhibited by the presence of persistent bracteoles, whereas, the annual A. prostrata has ephemeral bracteoles that may serve to limit germination in the fall but they are not present during the normal spring germination period. Bracteoles may play a significant role in the dispersal of seeds by water since seeds enclosed in bracteoles remained floating longer than seeds with the bracteoles removed.

Key words: Atriplex, bracteoles, dispersal, germination, salinity, seeds