Leaf tolerance to temperature and drought in plants from central-western Argentina: a comparative analysis facing global change.

GURVICH DE, FALCZUK V, DÍAZ S & CABIDO M.

Barcelona

Conferencia; GCTE-LUCC Open Science Conference on Global Change.; 1998

GCTE-LUCC

The knowledge of plant tolerance to climatic variables is highly relevant to the identification of Plant Functional Types (PFTs) within the context of climate change research. Very little has been published, however, comparing the tolerance to climatic variables of a wide range of species. We aimed at 1) developing a simple test of foliar  resistance to temperature and drought; 2) relating those responses with morpho/functional traits and geographical distribution of plants covering a wide range of growth forms, families, and habitats. We measured the percentage of  electrolyte leakage in leaf fragments of 54 species of vascular plants from  a precipitation and temperature gradient in Central- Western  Argentina. The treatments simulated frost (-8 C), chilling (1 C) high temperature (30 and 40 C) and drought. In general terms the method provided a good indication of the tolerance to the climatic variables analysed. It is also simple and unexpensive, and therefore suitable for comparative studies involving high numbers of species. In the data base analysed, resistance to high temperatures was significantly related with specific leaf area (-), leaf toughness (+), leaf lifespan (+), and significantly differed among PFTs. Resistance to low temperatures was significantly different among chorological types, average annual temperature of habitats of maximum abundance, and leaf lifespan (+). Resistance to drought was related to leaf toughness (+), thickness (+), and specific area (-). In general, PFTs and their associated traits explain plant tolerance to high temperatures and drought while the geographical distribution of species explains the resistance to low temperatures. Therefore, it may be important to consider variables related to climatic tolerance in the definition of PFTs. We discussed the possible vegetationresponses  under future climatic scenarios.