The Effect of Manganese on Pineapple Plants and the Ripening of the Pineapple Fruit

Abstract

The root system of pineapples growing on highly manganiferous soils was observed to be less extensive than on normal soils. A study was made of the pineapple fruit and leaves for the purpose of learning the structural changes produced by the presence of large quantities of manganese in the soil and the morphological changes that occur in the ripening of the fruit. The most conspicuous effect of manganese on this plant is seen in the bleaching of the chlorophyll, which first begins to fade, the chloroplasts lose their organized structure, and later the color disappears altogether. Oxalate of calcium is much more abundant in pineapple plants growing on manganiferous soils. The ash of such plants also contains considerably more lime and less phosphorus and magnesium than when grown on normal soils. At the time of the study, no method for ameliorating manganiferous soils was known, and it was recommended that they be used for crops more tolerant than pineapple.