Effects of Iron Deficiency on Respiration of Sunflower Plants

Abstract

1. Sunflower plants were grown in sand culture with nutrient solution. One group had iron salt as ferric citrate added to the nutrient solution; the other had no iron salt added. 2. The plants of the minus-iron treatment developed the typical chlorosis symptoms of iron deficiency; the controls were of normal color. 3. Respiration rate was depressed in the young chlorotic leaves of the iron deficient plants. 4- The chlorotic leaves of the iron-deficient plants contained only half as much iron as comparable leaves of control plants. No relocation of iron from older to younger leaves occurred in the iron deficient plants. In both the gradients were of decreasing iron content in going from the bottom to the top of the plants. 5. The iron contents of the leaves of a given plant of either treatment were found to be related to the ages of the leaves. The older contained more iron than the younger leaves.