TY - JOUR

T1 - Interactive effects of drought, elevated CO2 and warming on photosynthetic capacity and photosystem performance in temperate heath plants

AU - Albert, Kristian Rost

AU - Mikkelsen, Teis Nørgaard

AU - Michelsen, Anders

AU - Ro-Poulsen, Helge

AU - van der Linden, Leon

N1 - Copyright © 2011 Elsevier GmbH. All rights reserved.

PY - 2011

Y1 - 2011

N2 - Increased temperature, atmospheric CO(2) and change in precipitation patterns affect plant physiological and ecosystem processes. In combination, the interactions between these effects result in complex responses that challenge our current understanding. In a multi-factorial field experiment with elevated CO(2) (CO2, FACE), nighttime warming (T) and periodic drought (D), we investigated photosynthetic capacity and PSII performance in the evergreen dwarf shrub Calluna vulgaris and the grass Deschampsia flexuosa in a temperate heath ecosystem. Photosynthetic capacity was evaluated using A/C(i) curves, leaf nitrogen content and chlorophyll-a fluorescence OJIP induction curves. The PSII performance was evaluated via the total performance index PI(total), which integrates the function of antenna, reaction centers, electron transport and end-acceptor reduction according to the OJIP-test. The PSII performance was negatively influenced by high air temperature, low soil water content and high irradiance dose. The experimental treatments of elevated CO(2) and prolonged drought generally down-regulated J(max), V(cmax) and PI(total). Recovery from these depressions was found in the evergreen shrub after rewetting, while post-rewetting up-regulation of these parameters was observed in the grass. Warming effects acted indirectly to improve early season J(max), V(cmax) and PI(total). The responses in the multi-factorial experimental manipulations demonstrated complex interactive effects of T×CO2, D×CO2 and T×D×CO2 on photosynthetic capacity and PSII performance. The impact on the O-J, J-I and I-P phases which determine the response of PI(total) are discussed. The single factor effects on PSII performance and their interactions could be explained by parallel adjustments of V(cmax), J(max) and leaf nitrogen in combination. Despite the highly variable natural environment, the OJIP-test was very robust in detecting the impacts of T, D, CO2 and their interactions. This study demonstrates that future climate will affect fundamental plant physiological processes in a way that is not predictable from single factor treatments. The interaction effects that were observed depended upon both the growth strategy of the species considered, and their ability to adjust during drought and rewetting periods.

AB - Increased temperature, atmospheric CO(2) and change in precipitation patterns affect plant physiological and ecosystem processes. In combination, the interactions between these effects result in complex responses that challenge our current understanding. In a multi-factorial field experiment with elevated CO(2) (CO2, FACE), nighttime warming (T) and periodic drought (D), we investigated photosynthetic capacity and PSII performance in the evergreen dwarf shrub Calluna vulgaris and the grass Deschampsia flexuosa in a temperate heath ecosystem. Photosynthetic capacity was evaluated using A/C(i) curves, leaf nitrogen content and chlorophyll-a fluorescence OJIP induction curves. The PSII performance was evaluated via the total performance index PI(total), which integrates the function of antenna, reaction centers, electron transport and end-acceptor reduction according to the OJIP-test. The PSII performance was negatively influenced by high air temperature, low soil water content and high irradiance dose. The experimental treatments of elevated CO(2) and prolonged drought generally down-regulated J(max), V(cmax) and PI(total). Recovery from these depressions was found in the evergreen shrub after rewetting, while post-rewetting up-regulation of these parameters was observed in the grass. Warming effects acted indirectly to improve early season J(max), V(cmax) and PI(total). The responses in the multi-factorial experimental manipulations demonstrated complex interactive effects of T×CO2, D×CO2 and T×D×CO2 on photosynthetic capacity and PSII performance. The impact on the O-J, J-I and I-P phases which determine the response of PI(total) are discussed. The single factor effects on PSII performance and their interactions could be explained by parallel adjustments of V(cmax), J(max) and leaf nitrogen in combination. Despite the highly variable natural environment, the OJIP-test was very robust in detecting the impacts of T, D, CO2 and their interactions. This study demonstrates that future climate will affect fundamental plant physiological processes in a way that is not predictable from single factor treatments. The interaction effects that were observed depended upon both the growth strategy of the species considered, and their ability to adjust during drought and rewetting periods.

U2 - 10.1016/j.jplph.2011.02.011

DO - 10.1016/j.jplph.2011.02.011

M3 - Journal article

C2 - 21511363

VL - 168

SP - 1550

EP - 1561

JO - Journal of Plant Physiology

JF - Journal of Plant Physiology

SN - 0176-1617

IS - 13

ER -