ISSN: 2375-4397
Priya Khumukcham, Usha Mina*, Felicity Hayes, Kakul Smiti, Prachi Yadav
Tropospheric ozone (O3) acts as a phytotoxic secondary air pollutant and a potent greenhouse gas. O3 biomonitoring is a cost-effective approach compared to real time instrumental monitoring for identifying the potential effects of tropospheric O3 on crop growth and yield. In this study, eight Indian bean (Phaseolus vulgaris L.) genotypes were assessed for O3bio-monitoring potential along with the pre-identified O3-sensitive (S156) and O3 resistant (R123) bio-indicator Phaseolus genotypes provided by the international cooperative programme on effects of air pollution on natural vegetation and crops (ICP Vegetation), United Kingdom. One set of replicates was treated with the O3 protectant Ethylene-Di-Urea (EDU) while the other set was left under ambient environmental conditions without any treatment. The genotypes exposed to ambient O3 exhibited 0%-40% foliar ozone injury, though the timing of appearance of foliar O3 injury symptoms was variable among the genotypes. Plants treated with EDU exhibited lower foliar injury. Foliar O3 injury symptoms exhibited a significant positive correlation with cumulative O3 exposure (R2=0.73). The lipid peroxidation in bean plants under ambient O3 was observed to be 10%-62% greater than that of plants treated with EDU. The total protein and total carbohydrate content were also 4%-43% and 7%-40% lower, respectively, in leaves of plants exposed to ambient O3 as compared to plants treated with EDU. The results of the study indicate that the identified O3 sensitive genotypes of Phaseolus vulgaris viz. C1 (EC-755298) and C3 (IC-49810) can be used as O3 bio indicators for biomonitoring studies during the period between October and January in New Delhi, India.