Transient shade and drought have divergent impacts on the temperature sensitivity of dark respiration in leaves of Geum urbanum

Martijn Slot, Joana Zaragoza-Castells, Owen K. Atkin

    Research output: Contribution to journalArticlepeer-review

    35 Citations (Scopus)

    Abstract

    The respiratory response of plants to temperature is a critical biotic feedback in the study of global climate change. Few studies, however, have investigated the effects of environmental stresses on the short-term temperature response of dark respiration (Rdark) at the leaf level. We investigated the effect of shade and transient drought on the temperature sensitivity (Q10; the proportional increase in respiration per 10°C increase in temperature) of Rdark of Geum urbanum L. in controlled experiments. Shade effects were most pronounced following sustained, near-darkness, when rates of leaf Rdark at a set measuring temperature (25°C) and the Q10 of Rdark were both reduced. By contrast, rates of leaf Rdark and the Q10 of Rdark both increased in response to the onset of severe water stress. Water stress was associated with a rapid (but reversible) decline in rates of light-saturated photosynthesis (Psat), stomatal closure (g s) and progressive wilting. Re-watering resulted in a rapid recovery of Psat, gs and a decline in the Q10 of R dark (due to larger proportional reductions in the rate of R dark measured at 25°C compared with those measured at 14°C). The concentration of soluble sugars in leaves did not decline during drought (5-7 day cycles) or shading, but during drought the starch concentration dropped, suggesting starch to sugar conversion helped to maintain homeostatic concentrations of soluble sugars. Thus, the drought and shade induced changes in Rdark were unlikely to be due to stress-induced changes in substrate supply. Collectively, the data highlight the dynamic responses of respiratory Q10 values to changes in water supply and sustained reductions in growth irradiance. If widespread, such changes in the Q10 of leaf respiration could have important implications for predicted rates of ecosystem carbon exchange in the future, particularly in areas that experience more frequent droughts.

    Original languageEnglish
    Pages (from-to)1135-1146
    Number of pages12
    JournalFunctional Plant Biology
    Volume35
    Issue number11
    DOIs
    Publication statusPublished - 2008

    Fingerprint

    Dive into the research topics of 'Transient shade and drought have divergent impacts on the temperature sensitivity of dark respiration in leaves of Geum urbanum'. Together they form a unique fingerprint.

    Cite this