Changes in chlorophyll content, chlorophyllase activity, Hill reaction, photosynthetic CO2 uptake, sugar and starch contents in five dicotyledonous plants exposed to automobile exhaust pollution.

Exhaust gases from automobiles contribute significantly to environmental po llution. The effects of long term exposures to automobile exhaust on chloro phyll content, chlorophyllase activity, Hill reaction, photosynthetic CO2\ uptake, sugar and starch contents have been observed in five plants growing on the edge of Delhi Road (NH 2) near Dankuni, West Bengal. The same plant s collected from the nearby village at least 300 M away from the road serve d as control. Chlorophyll content decreased in Nerium, Boerhaavia and Taber naemontana with corresponding increase in chlorophyllase activity. It incre ased in Amaranthus and Cephalandra but the corresponding decrease in chloro phyllase activity was marginal. Hill activity and photosynthetic CO2 uptake decreased in Nerium, Boerhaavia and Amaranthus while both the activities i ncreased in case of Cephalandra whereas in case of Tabernaemontana, Hill ac tivity increased but photosynthetic CO2 uptake decreased. Soluble sugar and starch contents decreased in Nerium, Cephalandra and Tabernaemontana and b oth the contents increased in case of Amaranthus while in Boerhaavia starch increased but sugar content decreased.