| Abstract: | The differential tolerance of resislant creeping red fescue (Fes- tuca rubra L, var, rutra) and susceptibie reed canarygrass (Pha- laris arundinacea L.) seedlings to glyphosate N-(phosphono- meihyDglycine) was confirmed under growth chamber condilions. The absorption, transiocation and metabolism of 14C-glyphosate was examined in both species to determine if differences in these processes could account for the observed selectivity, Creepmg red fescue actually absorbed more glyphosate than did t-eed canarygrass, and both species rapidly translocated the herbicide throughout their respective tissues. No metabolism of glyphosate was detected in either species. Differential interception and retention of the glyphosate spray can probably be eliminated as possible selectivity mechanisms. The relative tolerance of creeping red fescue to glyphosale appears to be related to its ability lo regenerate roots and shoots from the crown of the plant, but the mechanism of resistance remains obscure. |
