MULBERRY LEAVES AS A BIOINDICATOR OF FLUORIDE POLLUTION IN THE VICINITY OF A PHOSPHATE FERTILIZER FACTORY LOCATED IN SFAX, TUNISIA.

Since the response of plant species to air pollutants is variable, the classification of plants into sensitive and tolerant groups is vital because the former can serve as biological indicators and the latter as sinks for the air pollutants. The morphological, biochemical, and physiological effects of fluoride stress were investigated in mulberry plants (Morus alba L.) grown at different distances from a phosphate fertilizer factory in Tunisia. Gas exchange (photosynthetic rate, stomatal conductance, and transpiration rate), photosynthetic pigments (chlorophyll and carotenoids) and water status (leaf relative water content) were decreased in the mulberry leaves grown near the polluted sites. However, lipid peroxidation (malondialdehyde content) and osmotic regulator (proline and soluble sugars content) levels were increased as compared to the control site. The obtained results suggest that Morus alba leaves could be considered as an air pollution bioindicator. [ABSTRACT FROM AUTHOR]