The relationship between the constitution and the effect of chemical compounds on plant growth. V.—aromatic nitro‐compounds and nitramines

Abstract

AbstractThe root growth of germinating seeds of rape and wheat is markedly reduced when the seeds are grown in the presence of certain aromatic nitro‐compounds. No correlation is apparent between the toxicity and the chemical reactivity, but within comparable groups of compounds water‐solubility appears to be a limiting factor governing toxicity. Methylation of nitrophenols modifies their toxicity but does not destroy it.Arynitramines of the formula Ar‐NH‐NO2 are selective inhibitors of the root growth of rape as compared with wheat. The activity is believed to be associated with the acidic nature of the nitramine group and is affected by the nature of the substituents in the benzene ring. The arylnitramines inhibit the geotropic response of roots of rape and ryegrass, and in four out of seven compounds examined the phototropic response of shoots of rape and rye‐grass was also inhibited.