Relationships between needle nitrogen concentration and photosynthetic responses of Douglas‐fir seedlings to elevated CO₂ and temperature

Abstract

Summary• Here we examined correlations between needle nitrogen concentration ( [N]) and photosynthetic responses of Douglas-fir ( Pseudotsuga menziesii ) seedlings to growth in elevated temperatures and atmospheric carbon dioxide concentrations ([CO 2 ]).• Seedlings were grown in sunlit, climate-controlled chambers at ambient or ambient +3.5 ° C and ambient or ambient +180 µmol mol − 1 CO 2 in a full factorial design. Photosynthetic parameters and needle [N] were measured six times over a 21-month period.•

Biochemical acclimation, stomatal limitation and precipitation patterns underlie decreases in photosynthetic stimulation of soybean (Glycine max) at elevated [CO2] and temperatures under fully open air field conditions

“…350 ppm moderate increases in temperature may have little effect on V c,max as long as growth temperatures remain below the photosynthetic optimum; when growth temperatures consistently exceed the temperature optimum of A, V c,max down-regulates significantly [3,6]. On average, J max acclimates more than V c,max at higher growth temperatures [44][45][46] and less than V c,max at elevated CO 2 . Here, V c,max@25 did not detectably change in response to elevated temperature when averaged for the entire season in either year suggesting that plant canopy temperatures did not exceed the temperature optimum of A.…”

“…Moderately elevated temperature alone (i.e. +4 • C) has been reported to either increase [43,44], decrease [3,6,43] or not change V c,max [43]. At [CO 2 ] of ca.…”

Effects of soil warming and nitrogen fertilization on leaf physiology of Pinus tabulaeformis seedlings

“…On the other hand, nitrogen deposition is another crucial environmental change, and it is seriously affecting terrestrial and aquatic ecosystems. Nitrogen also acts as one of the key resources likely to regulate plant responses to climate warming (Lewis et al 2004).…”

Climate change effects on vegetation in the Pacific Northwest: a review and synthesis of the scientific literature and simulation model projections

“…Increasing mean annual temperatures are likely to increase photosynthetic rates for many temperate plant species, given suffi cient light and water (Saxe et al 2001 plant photosynthetic rates indirectly by changing leaf nitrogen content and photosynthetic capacity (Lewis et al 2004). In Douglas-fi r (Pseudotsuga menziesii (Mirb.…”

“…Franco) seedlings, for example, experimental warming increased chlorophyll and carotenoid concentrations (Ormrod et al 1999) and increased seedling needle nitrogen (N) concentrations by 26 percent and light-saturated photosynthetic rates by 17 percent (Lewis et al 2004). Warming temperatures are not uniformly beneficial for photosynthesis, however, as temperatures in excess of the photosynthetic optimum can rapidly reduce photosynthesis by impairing protein functioning (Saxe et al 2001) and high daytime temperatures can reduce net photosynthesis by increasing rates of photorespiration (Long et al 1994).…”