Comparative Effects of Aromatic Compounds on Inhibition of Lettuce Fruit Germination

Abstract

Germination of lettuce (Lactuca sativa L. cv. Great Lakes) was inhibited by aromatic alcohols, aldehydes and carboxylic acids in a way similar to that by aliphatic members. Increased lipophilicity usually leads to increased inhibitory activity. Thus methylation increased activity while hydroxylation decreased it. Exceptions were seen with ortho-hydroxylated compounds and other exceptions indicated the presence of unrecognized factors. Many of the phenolic compounds often quoted as inhibitors were shown to be not particularly activeagainst lettuce germination when compared with, for instance, abscisic acid or coumarin.