Lichen’s Adaptation to Altitude

Abstract

Lichens from alpine regions and from areas of high altitudes are subject to the effects of high UV radiation levels, which have increased in the last decades due to the decrease of ozone, and they have developed chemical strategies to diminish the stress of the environment.The phenolic products absorbing properties of UV-A, UV-B, or both, agree with their photoprotector capacity determined by-in vivo and in vitro methods. Rhizoplaca chrysoleuca., Xanthoparmelia farinosa and Xanthoparmelia oleosa accumulate usnic acid, appart from other secondary products. In transects performed in the Chilean Altiplano, between 3100 and 4500m a.s.1., a growing increment of usnic acid, with altitude and total UV radiation, was observed. The usnic acid increments are evidenced in intervals of some kilometers, in zones with high solar irradiance.The lichen adaptative capacity to radiation is expressed in the spatial and temporal variations of secondary products in habitats having different degrees of insolation.