Effect of Cement Dust Pollution on Morphology and Photosynthetic Pigments of Some Legume Plants Grown in Ariyalur District, Tamil Nadu

Air pollution has assumed a mammoth proportion in recent times because of causation of health hazards and loss of economic productivity of crop plants. The present study was carried out to assess the impact of cement klin dust pollution on some selected legume crops viz. Arachis hypogaea, Vigna mungo, V. radiate, Dolichos lablab and Cajanus cajan which are grown around the cement industry. Effect of cement dust on morphology, photosynthetic pigments, proline and total phenol content was studied in the plants collected near the factory site (Polluted) and 15 km away from the factory site (Control). Cement crust formation on leaf surfaces was evident in plants growing in polluted site. The Chlorophyll pigments were reduced in dust-exposed plant species compared with control, wherein a reduction up to 88 % was noted. Of the chlorophyll greater reduction was observed in chl b. The chl a/b ratio, chl/carotenoid ratio was also reduced. Further there was increase in accumulation of the stress indicators proline and phenols. In general, pollution by the cement dust has caused adverse effects on the photosynthetic pigments. Of the selected plants A. hypogaeae was more resistant to dust pollution followed by C. cajan and V. mungo. The decrease in the chlorophyll/carotenoid ratio in stressed plants suggested that these relationships could be used as an indicator of tolerance and physiological status of the plants under cement dust stress conditions.