Effect of mineral deficiency on amine formation in higher plants

Abstract

Potassium deficiency caused putrescine accumulation in the leaves of barley, radish, pea, bean and spinach plants. Magnesium deficiency caused putrescine accumulation in barley, pea and bean leaves, and also in the leaves of older radish plants. In young radish plants less putrescine was found in magnesium deficiency, and in spinach magnesium deficiency was without effect on putrescine levels. Putrescine content may be a useful guide to the mineral status of legumes, since accumulation of this amine may be detected before deficiency symptoms appear. Radioactivity from l-arginine-[U- 14C] fed to barley seedlings was detected in agmatine within 2 hr, and probably also in the hordatines after 24 hr, feeding. After 2 hr the label in the agmatine was greatest in the potassium-deficient plants, but after 24 hr the level declined to that found in the agmatine of the leaves of the magnesium-deficient and control seedlings. The rate of putrescine formation was high in both potassium and magnesium deficiency. Incorporation of radioactivity in spermidine and spermine on feeding putrescine-[1,4- 14C] to barley seedlings was estimated in the dansylated amines after separation by TLC. Activity was higher in spermidine and lower in spermine in the potassium-deficient plants than in the controls. The spermidine/spermine ratio declined on excision of barley leaves.