SOME EFFECTS OF POTASSIUM DEFICIENCY ON THE METABOLISM OF THE TOMATO PLANT

Abstract

The organic and keto acid levels in the leaves of tomato plants grown with varying levels of potassium were examined. As the potassium level was reduced, the levels of malic, oxalic, and sometimes pyruvic acids decreased, while citric, α-ketoglutaric, and glyoxylic acids accumulated. Total organic acids remained almost constant at all potassium levels, while such changes as occurred in cation levels were balanced by phosphate. These relationships held for plants grown under widely different environmental conditions and were not affected by the age of the plants. It is suggested that the changes in acid balance were brought about by changes in the activity of enzymes concerned in pyruvate metabolism and by shifts in equilibrium caused by free amino acids and amides accumulated as a result of deranged protein metabolism.