Mountains in the Chaning World, Mountains in the Chaning World

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Effect of temperature and precipitation on usnic acid production in Parmelia flexilis grown at different altitudes of Nepal.
Bishnu Prasad Neupane

Last modified: 2017-08-31


Climate change factors such as temperature and parecipitaion found to have an important impact on lichen metabolite, usnic acid. In this talk, we would present evidence that there appears to be a reciprocal relationship between the usnic acid and altitude gradients. Thirty one samples of lichen Parmelia flexilis were collected from different altitudes (841-2250 m asl)) and determined usnic acid concentration quantitatively using high performance liquid chromatography (HPLC). The amount of usnic acid varied in between highest 5.13% to lowest 1.66% in oven dried (80oC) lichen samples. The species collected from lower altitudes all show high levels of usnic acid. The negative relationship between usnic acid and altitude was obtained. Statistically, it is revealed that there is a significant difference between average percentages of usnic acid in lichen samples with varying altitudes (p < 0.05). Beside these, the precipitation averages of the regions where the species have been collected were linked with the content of usnic acid. It is clear that lichens from the regions receiving the highest precipitation produced lower amounts of usnic acid. The results suggest that the production of secondary metabolite in lichens is also altered due to the climate variables like temperature and precipitation at different altitude gradients.

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