Plant and Soil

, Volume 240, Issue 2, pp 343–352

Ecophysiological significance of chlorophyll loss and reduced photochemical efficiency under extreme aridity in Stipa tenacissima L.

Authors

    • Departamento de Biología Vegetal I, Facultad de BiologíaUniversidad Complutense
  • F. I. Pugnaire
    • Estación Experimental de Zonas Áridas. Consejo Superior de Investigaciones Científicas
  • E. Martínez-Ferri
    • Departamento de Biología Vegetal I, Facultad de BiologíaUniversidad Complutense
    • Departamento de Biología Vegetal II, Facultad de FarmaciaUniversidad Complutense
    • Plant Sciences, Faculty of AgricultureThe University of Western Australia
  • C. Armas
    • Estación Experimental de Zonas Áridas. Consejo Superior de Investigaciones Científicas
  • F. Valladares
    • Centro de Ciencias Medioambientales. Consejo Superior de Investigaciones Científicas
  • E. Manrique
    • Departamento de Biología Vegetal II, Facultad de FarmaciaUniversidad Complutense
Article

DOI: 10.1023/A:1015745118689

Cite this article as:
Balaguer, L., Pugnaire, F.I., Martínez-Ferri, E. et al. Plant and Soil (2002) 240: 343. doi:10.1023/A:1015745118689

Abstract

Stipa tenacissima L., a perennial tussock grass widely found in semi-arid environments of the Iberian Peninsula and North Africa, is subjected to multiple stresses during the extreme summer conditions of south-east Spain. We characterised the photoprotective mechanisms of S. tenacissima during the transition from spring to summer and autumn. S. tenacissima experienced a marked water deficit (Ψ{ pd} < -8.4 MPa) and the complete suppression of CO2 assimilation in August, associated with a 72% reduction of maximal photochemical efficiency of PSII (F{ v}/F{ m}). These reduced F{ v}/F{ m} values were related to the pre-dawn maintenance of high levels of epoxidized forms of xanthophyll-cycle pigments (DPS{ pd}, ca. 42% higher than spring values), and with a 60% reduction in the concentration of total chlorophyll (Chl a+b). These changes were associated with a low capacity of dissipation of the excitation energy non-radiatively (measured as NPQ). Leaves showed a complete recovery of F{ v}/F{ m} and xanthophyll and chlorophyll concentrations after the autumn rainfall, which reached levels similar to that of spring. This poikilohydric-type response of S. tenacissima to stress allows for a greater tolerance of water shortage, high temperature and high light intensity, which are typical in these semi-arid environments and accounts for its distinctive opportunistic growth.

arid environmentsdroughtphotoprotective pigmentspoikilochlorophyllypoikilohydryStipa tenacissima
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© Kluwer Academic Publishers 2002