Abstract

                                An experiment was conducted at woodhouse farm, Horticultural Research Station, Ooty, in the period of October 2017 to March 2018, to quantify the impact of tropospheric ozone and ozone protectants spray on chlorophyll content and antioxidant enzyme levels of cauliflower crop in a factorial completely randomized block design replicated thrice. During the study period, the plant exposed to ambient ozone level + 3% Panchagavya foliar spray had higher chlorophyll ‘a’, chlorophyll ‘b’ and total chlorophyll. The ambient ozone level + 3% Neem oil foliar spray had significantly higher total nitrogen, total phosphorous, total potassium. The elevated ozone exposure at 200 ppb significantly reduced the, total nitrogen, total phosphorous, total potassium, Chlorophyll ‘a’, Chlorophyll ‘b’, total chlorophyll and increased catalase and peroxidase enzyme activities in cauliflower plant. It is concluded that the tropospheric ozone had detrimental effect on chlorophyll contents and anti-oxidant enzymes in cauliflower crop. Further, the ozone protectants played a major role to nullify the tropospheric ozone effect on growth, physiology, development and yield of cauliflower and among the protectents, panchagavya performed well followed by neem oil and ascorbic acid.

Key words : Elevated ozone, Chlorophyll, Anti-oxidative enzymes, Cauliflower crop.