Sammanfattning

Previous leaf-scale studies of carbon assimilation describe short-term resource-use efficiency (RUE) trade-offs where high use efficiency of one resource requires low RUE of another. However, varying resource availabilities may cause long-term RUE trade-offs to differ from the short-term patterns. This may have important implications for understanding canopy-scale resource use and allocation. We used continuous gas exchange measurements collected at five levels within a Norway spruce, Picea abies (L.) karst., canopy over 3 years to assess seasonal differences in the interactions between shoot-scale resource availability (light, water and nitrogen), net photosynthesis (A(n)) and the use efficiencies of light (LUE), water (WUE) and nitrogen (NUE) for carbon assimilation. The continuous data set was used to develop and evaluate multiple regression models for predicting monthly shoot-scale A(n). These models showed that shoot-scale A(n) was strongly dependent on light availability and was generally well described with simple one- or two-parameter models. WUE peaked in spring, NUE in summer and LUE in autumn. However, the relative importance of LUE for carbon assimilation increased with canopy depth at all times. Our results suggest that accounting for seasonal and within-canopy trade-offs may be important for RUE-based modelling of canopy carbon uptake.Resource use efficiency (RUE) is a key trait in determining the ability of plants to assimilate carbon. We demonstrate that the use efficiencies of light, water and nitrogen in determining the shoot-scale carbon uptake peak at different times of the year in a Norway spruce canopy, but also that the RUE interaction becomes increasingly dominated by light use efficiency with canopy depth at all times of the year. These temporal and spatial patterns in RUE interactions may have important implications for within-canopy resource allocation and for RUE-based modelling of canopy-scale carbon uptake. The study was based on continuous half-hourly gas exchange measurements conducted over a period of three years along a vertical canopy gradient in a mature Norway spruce stand.

Nyckelord

Picea abies; light-use efficiency; nitrogen-use efficiency; photosynthesis; stomatal conductance; transpiration; water-use efficiency

Publicerad i

Plant, Cell and Environment
2015, Volym: 38, nummer: 11, sidor: 2487-2496
Utgivare: WILEY-BLACKWELL

SLU författare

• Tarvainen, Lasse

  • Institutionen för skogens ekologi och skötsel, Sveriges lantbruksuniversitet
    
  • Göteborgs Universitet

Globala målen

Skydda, återställa och främja ett hållbart nyttjande av landbaserade ekosystem, hållbart bruka skogar, bekämpa ökenspridning, hejda och vrida tillbaka markförstöringen samt hejda förlusten av biologisk mångfald


UKÄ forskningsämne

Skogsvetenskap


Publikationens identifierare

DOI: https://doi.org/10.1111/pce.12565

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/68881