Effect of sulphur dioxide pollution on ornamental species of CACTI

An experiment was conducted to observe the effect of SO₂ on two ornamental species of cacti namely Opuntia ficus indica and Chaemocereus sylvestris. The group of plants were exposed to different concentration of sulphur dioxide which at 1306 μgm^-3, 2612 μgm^-3 and 5224 μgm^-3 concentration reduced the growth rate of cacti. The maximum reduction recorded in shoot length was 12.65 cm at 5224 μgm^-3 SO₂ concentration. Significant reduction in fresh and dry weight of roots and shoot-root ratio was also observed. However no significant reduction was found in terms of fresh and dry weight of shoots. A gradual reduction in stomatal frequency and stem moisture content was also recorded. The number of stomata was reduced to 3.0 per unit area in Chaemocereus sylvestris and 3.2 in Opuntia ficus indica at 5224 μgm^-3 concentration of SO₂. It was concluded that changes in most of morphological, biochemical and stomatal parameters were directly propprtional to the amount of pollutant