MINERAL COMPOSITION OF CHLOROTIC ORANGE LEAVES AND SOME OBSERVATIONS ON THE RELATION OF SAMPLE PREPARATION TECHNIQUE TO THE INTERPRETATION OF RESULTS

Abstract

Leaves from orange trees on a highly acid, sandy soil were used as test material for studies on prepn. of samples for analysis. 11 mineral elements were detd. Leaves showing an iron-chlorosis pattern were found to be relatively lower in Ca, Mg, Fe, Mn, Cu, and B than green leaves from adjacent trees. They were likewise higher in N, P, K, and Na. Minimal values for Fe, Al, and Cu were obtained by scrubbing in a neutral detergent and rinsing adequately. Sprayed leaves gave lowered Fe, Cu, and Zn values when washed in an acidulated detergent soln.; but there is some doubt that surface contamination is completely removed by such treatment. Total iron content showed a strong inverse relationship to the degree of iron-chlorosis. Mn, also, was abnormally low in leaves showing this type of leaf pattern. The macro-nutrient elements were not influenced by the various washing treatments used.