Variación altitudinal de los atributos morfo-fisiológicos en dos especies de plantas alto-andinas y sus implicancias contra la fotoinhibición/Altitudinal variation of morpho-physiological traits in two High-Andean plant species and its effects against the photoinhibition

摘要

High-mountain environments are characterized by stressful climatic conditions for the development of plants. Some of these conditions are low temperatures of air and soil, high radiation, and water shortage. It has been documented that high radiation and low temperatures are favorable conditions for inducing photoinhibition. Nevertheless, there are plant species that successfully live on extended altitudinal gradients, suggesting the presence of strategies to cope with stressful climatic conditions. In this study we assessed the different photoprotective strategies, both morphological and physiological in Taraxacum officinale G.Weber ex F.H.Wigg. (Asteraceae) and Phacelia secunda F.J.Gmel. (Hydrophyllaceae) growing in two populations. Physiological and morphological traits were recorded in both species growing at 2,600 y 3,600 m, in Los Andes of Central Chile. Overall, results indicate that T. officinale showed variations in four of the six morphological traits recorded between altitudes; however, P. secunda showed high morphological variations among populations in all of its traits. On the other hand, T. officinale individuals growing in the upper population significantly showed a higher amount of pigments involved in xanthophyll cycle, while P. secunda showed no differences, suggesting that T. officinale has most capacity for dissipation of the solar energy as heat. In both species, the desepoxidation status was significantly higher in those individuals from upper populations. Results suggest that while T. officinale has mainly a physiological strategy to cope with the photoinhibitory conditions in the high-mountain, P. secunda has a strategy mainly based in morphological variations. Therefore, the presence of specific plant species in the high-mountain habitats should be related with the different strategies for avoiding fotoinhibition by high radiation and low temperature, which are typical from the high-mountain habitats of Central Chile. [PUBLICATION ABSTRACT]