THE STUNTED FRUIT DISORDER - A PHYSIOLOGICAL ANOMALY IN MANGO (MANGIFERA-INDICA L) CAUSED BY A FLUORINE POLLUTANT

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