The differential effect of synthetic plant growth substances and other compounds upon plant species I. Seed germination and early growth responses to α -naphthylacetic acid and compounds of the general formula arylOCH 2 COO R

Abstract

Laboratory and small-scale experiments in soil are described in which α -naphthylacetic acid in solution, incorporated dry in fine sand and in ammonium sulphate, has been applied to oats ( Avena saliva L.) and yellow charlock ( Brassica Sinapis Visiani) at seed sowing and during early growth stages. Concentrations which kill the charlock leave the oats unharmed. Details are given of other weeds which react similarly to yellow charlock, whilst other cereals (wheat, barley and rye) behave like oats. The chemical syntheses of a number of compounds of the general formula arylOCH 2 COO R , where the aryl radicle was benzene or naphthalene, with and without substituents, and R was hydrogen, an alkali metal or an alkyl radicle, are described. The biological examination of these compounds is described and certain characteristics of the more active ones indicated and discussed. The practical importance of this discovery in the field of weed-killers which selectively eradicate weeds from cereal crops is pointed out. The incorporation of active materials in fertilizers for cereal crops is suggested. A program m e of research on this subject is proceeding.