Physiological alterations and heavy metal accumulation in the transplanted lichen Pyxine cocoes (Sw.) Nyl. in Lucknow city, Uttar Pradesh.

Air pollution has become a major concern due to its detrimental effects on living beings. The present study is aimed at assessing the current status of air pollution in Lucknow city using lichen transplantation technique and assesing its effect on physiology of Pyxine cocoes. The samples of P. cocoes were collected from relatively pollution-free area Malihabad and transplanted in 10 designated sites in five regions for 30 days. Various parameters such as heavy metals, chlorophyll pigments, carotenoid, chlorophyll degradation, and electrolyte conductivity were estimated in transplanted lichens. The study revealed that the concentration of all 10 heavy metals was higher in all transplanted samples than in the control sample, which was found in order of Al > Fe > Mn > Zn > Cu > Cr > Pb > Ni > Co > Cd. Among all 10 transplanted sites, the significantly increased accumulation of aluminum (5.11 to 5.47 µg L), iron (4.73 to 5.46 µg L), manganese (110.99 to 144.58 µg g), and zinc (87.96 to 97.40 µg g) was found in Charbagh, Qaisarbagh, and Alambagh sites. Further, in all samples, chlorophyll a (3.98 µg L), chlorophyll b (1.22 µg L), total chlorophyll (5.20 µg L), and chlorophyll degradation (0.55 µg g) were significantly decreased, whereas elevated levels of carotenoid (0.71 µg g), and electrolyte conductivity (64.99 µS cm), were observed. The scanning electron microscope (SEM) investigated the morphological changes in transplanted lichen samples, and significant damage to the anatomy of mycelium was found in most of the polluted site's samples, which correlated with the pollution levels. The present study clearly demonstrated that the transplanted lichen P. cocoes is an efficient bioaccumulator and bioindicator of air quality in urban environments.