Chlorosis in higher plants as related to organic acid content.

In recent years comparative studies have been made betwveen chlorotic plants and healthy plants to determine if any consistent distortion of the normal metabolic pattern occurs irrespective of the cause of chlorosis. Experiments by Iljin (6) indicated a greater amino acid and organic acid content in chlorotic leaves from grape plants grown on calcareous soil than in normal green leaves. DeKock et al (4) also found that significantly larger amounts of free amino acids and organic acids were associated with tissue in which chlorosis was present. Rhodes et al (11) observed that aspartic and glutaniic acids which are formed directly from organic acids were present in high concentrations in lime-induced chlorotic bean leaves. From earlier studies we may assume that the disorders in metabolism associated with chlorosis in higher plants, such as blocks in the pathways for synthesizing amino acids and proteins from organic acids, or abnormal operations of the TCA cycle are either causative factors or the result of chlorosis. In this study, in order to gain more evidence for the mechanisms by which chlorosis is induced, comparative studies on the organic acid fractions between chlorotic and healthy leaves were conducted. Chlorosis was induced in the experimental plants by high phosphorous, manganese, bicarbonate, or iron deficiency.