Are heat and cold resistance of arctic species affected by successive extreme temperature events?

FL Marchand, F Kockelbergh, B van de Vijver, L Beyens, I Nijs

    Onderzoeksoutput: Bijdrage aan tijdschriftA1: Web of Science-artikel

    Uittreksel

    Extreme temperature events are projected to increase in frequency in a future climate. As successive extremes could occur more frequently, patches of vulnerable tundra vegetation were exposed to two consecutive heat waves (HWs) of 10 d each, with a 5-d recovery period in between. Surface temperatures during the HWs were increased approximately 6 degrees C using infrared irradiation sources. In three of the four target species (Pyrola grandiflora, Polygonum viviparum and Carex bigelowii), plant conditions improved upon the first exposure. Depending on species, leaf relative growth, leaf chlorophyll content or maximal photochemical efficiency was increased. In P. grandiflora the positive effects of the heat on the photosynthetic apparatus led to augmented net photosynthesis. By contrast, Salix arctica responded mainly negatively, indicating species-specific responses. During the second HW, leaf mortality suddenly increased, indicating that the heat stress induced by the extreme events lasted too long and negatively influenced the species resistance to high temperature. After the HWs, when plants were exposed to (low) ambient temperatures again, plant performance deteriorated further, indicating possible loss of cold resistance.
    TaalEngels
    TijdschriftNew Phytologist
    Volume170
    Exemplaarnummer2
    Pagina's (van-tot)291-300
    Aantal pagina's10
    ISSN0028-646X
    DOI's
    StatusGepubliceerd - 2006

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