Role of endogenous histamine in the germination of Pisum sativum, L

Abstract

The effects of aminoguanidine (diamine-oxidase inhibitor) and semicarbazide (his- tidine-decarboxylase inhibitor) on germinating Pisum sativum are studied in order to find any possible correlation between histamine metabolism and plant growth. It is know that germinating peas are rich in diamine-oxidase.

Aminoguanidine strongly stimulated the growth of pea seedlings when its concen­ traron in the bathing liquid was about 10“* M. At higher level (10~3 M) an increase followed by a delay in the rate of growth was observed. The highest concentration tested (10-2 M) showed up its great toxicity. The histamine content in plants treated with aminoguanidine is higher than the content in control plants.

Semicarbazide 10-4 M, 10-3 M and 10~2 M inhibited the growth of the pea seedl­ ings, the stronger the concentration the bigger the effect. The histamine content of plants treated with the smaller concentrations showed no significativo difference with Controls.

These facts are compared with former data gathered by us for wheat seedlings, and with those quoted by other workers.