Fe‐deficiency stress tolerance and pH reduction: Some contrasts in the cultivars of sesame and lentil

Abstract

Fe‐deficiency chlorosis was induced in 4 lentil (Lens esculenta Moench) and 7 sesame (Sesamum indicum L.) cultivars by growing them in full nutrient solution for 20 days and then in the nutrient medium without Fe. In lentil cv. VL‐1, a mild chlorosis appeared but turned green after 14 days of stress. However, this recovery was not paralleled by a decrease in pH of the medium. In sesame, there were differences in the degree of tolerance. The cv. T‐13 did not develop any chlorosis, and the pH was found to steadily decrease to 4.5. The cv. SP‐1181 lowered the pH to only 5.6, and did not recover from the chlorosis. A second pattern was noted in VS‐2, TS‐25, TMV‐3 and TMV‐4; these cultivars reduced the pH to between 4.1 and 4.5; these showed a mild chlorosis which disappeared later.

The results show that the pH reduction is not a requisite for chlorosis recovery, at least in some crop cultivars. There are obviously some other mechanism which makes Fe available to the chlorotic leaves. It is suggested that a retranslocatlon of Fe from the older leaves may take place under the stress condition through some physiological process.

Key words:

• Fe‐stress response
• cultivar differences
• lentil
• sesame
• pH reduction