The stunted fruit disorder—A physiological anomaly in mango (Mangifera indica L.) caused by a fluorine pollutant

Summary

The stunted mango fruit disorder (SFD) is characterized by small-sized fruit, stiffened pulp tissue and failure to ripen at harvest. A cabinet fumigation trial with potted fruiting mango trees was carried out to investigate the cause of this disorder. Treatment with hydrogen fluoride (12 μg HF m^–3 and 24 μg HF m^–3) succeeded in inducing the typical symptoms of SFD, while treatment with sulphur dioxide (800 μg SO₂ m^–3) failed. Inhibition of cell expansion growth was observed in SFD fruits. The cells of affected fruits were much smaller than those of normal fruits at the same growth stage. Although reduction of photosynthesis of mango leaves was seen under both HF and SO₂ fumigation treatments, it did not seem to limit fruit growth. The leaf and fruit fluorine (F) or sulfur (S) contents increased in HF or SO₂ fumigation treatments. Fluorine pollutant in the smoke emitting from brick-kilns or aluminum factories must be the direct cause of SFD.