Cement dust effects on biochemical responses of castor (Ricinus communis) collected from Bir Mcherga (northwest of Tunisia)

In this study, we evaluated the impact of air pollution caused by the cement dust on the biochemical response of castor by measuring chlorophylls, carotenoids, antioxidant activity, phenolic compounds, fatty acid composition, etc. Our results indicated that cement pollution induced a lipid peroxidation in castor leaves as estimated by the increased production of malondialdehyde, which is the main cause of generation of excessive free radicals. Our results show that in response to the accumulation of malondialdehyde, the levels of total soluble sugar (TSS) and proline increase especially in the leaves of plants collected right next to the source of the pollution (site 2). This accumulation can explain the protective role of TSS and proline against the damage that might have occurred due to oxidative stress. Pollution resulted in an increase in the total phenolics and flavonoid levels in castor leaves. Our results suggest that phenolic compounds may play a crucial role in plant defense against oxidative stress. Our findings indicated that pollution-induced stress tends to reduce the level of unsaturated fatty acids in castor leaves by reducing UFA, especially α-linolenic and linoleic acids. They also reveal the suitability of using castor plants in the creation of green areas around cement factories and encourage the use of dusted plants as potential source of valuable natural products.