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Optimization of photosynthesis and stomatal conductance in the date palm Phoenix dactylifera during acclimation to heat and drought
Author(s) -
Kruse Jörg,
Adams Mark,
Winkler Barbro,
Ghirardo Andrea,
Alfarraj Saleh,
Kreuzwieser Jürgen,
Hedrich Rainer,
Schnitzler JörgPeter,
Rennenberg Heinz
Publication year - 2019
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/nph.15923
Subject(s) - phoenix dactylifera , palm , stomatal conductance , acclimatization , photosynthesis , transpiration , botany , biology , stomatal density , physics , quantum mechanics
Summary We studied acclimation of leaf gas exchange to differing seasonal climate and soil water availability in slow‐growing date palm ( Phoenix dactylifera ) seedlings. We used an extended Arrhenius equation to describe instantaneous temperature responses of leaf net photosynthesis ( A ) and stomatal conductance ( G ), and derived physiological parameters suitable for characterization of acclimation ( T opt , A opt and T equ ). Optimum temperature of A ( T opt ) ranged between 20–33°C in winter and 28–45°C in summer. Growth temperature ( T growth ) explained c . 50% of the variation in T opt , which additionally depended on leaf water status at the time of measurement. During water stress, light‐saturated rates of A at T opt (i.e. A opt ) were reduced to 30–80% of control levels, albeit not limited by CO 2 supply per se . Equilibrium temperature ( T equ ), around which A / G and substomatal [CO 2 ] are constant, remained tightly coupled with T opt . Our results suggest that acclimatory shifts in T opt and A opt reflect a balance between maximization of photosynthesis and minimization of the risk of metabolic perturbations caused by imbalances in cellular [CO 2 ]. This novel perspective on acclimation of leaf gas exchange is compatible with optimization theory, and might help to elucidate other acclimation and growth strategies in species adapted to differing climates.