Physiological and yield responses of pea plants to ambient air pollution

The study aimed to assess the effect of ambient air pollution on physiological as well as yield characteristics of pea plants grown at different sites in the periurban area of Varanasi city. Assessment of selected parameters such as photosynthesis rate, stomatal conductance, transpiration rate, water use efficiency, pigment concentrations, yield and quality of seeds were made in relation to ambient concentrations of SO₂, NO₂ and O₃. The ambient levels of all the pollutants were lowest at site 1 (BHU), and hence this site was treated as reference site for comparing the response pattern observed at other sites. Photosynthetic rate and water use efficiency declined at sites 2 to 6 in response to ambient levels of pollutants. Stomatal conductance did not correspond directly to the lowering of photosynthesis. Total chlorophyll content and yield were less at sites 2 to 6 compared to reference site 1. Seed quality in terms of metabolite and nutrient contents also deteriorated at sites receiving higher pollution load. The study indicated that ambient air pollution has potential negative impact on physiological characteristics of pea plants, which led to lower yield and inferior quality of seeds at sites in periurban areas experiencing higher levels of pollutants.