Premium
Analysis of differences in photosynthetic nitrogen‐use efficiency between four contrasting species
Author(s) -
Pons Thijs L.,
Westbeek Milka H. M.
Publication year - 2004
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.2004.00380.x
Subject(s) - biology , botany , photosynthesis , nutrient , chlorophyll , nitrogen , horticulture , chemistry , ecology , organic chemistry
Causes of differences in photosynthetic nitrogen‐use efficiency (PNUE), the rate of photosynthesis per unit leaf N, were investigated in four species. These were in order of decreasing PNUE; the two herbs Galinsoga ciliata and Origanum vulgare , and the two trees Populus nigra and Quercus robur . Plants were grown in pots outdoors at three levels of nutrient availability. The light‐ and CO 2 response of gas exchange of leaves were measured, and their nitrogen and chlorophyll contents were determined. Furthermore, the internal conductance for CO 2 diffusion was estimated. Nutrients did not have a large effect on PNUE except in Galinsoga . Leaf mass per unit area was negatively correlated with PNUE max , which is likely to be partly caused by N present in cell wall proteins among other non‐photosynthetic N compounds. The trees had a larger fraction of photosynthetic N in light harvesting components compared to the herbs. This contributed also substantially to the difference in PNUE at light saturation (PNUE max ) between the two groups, but not for PNUE calculated for an overcast day. Intercellular CO 2 concentration was high in Galinsoga and Populus , which contributed significantly to their higher PNUE max , particularly at low nutrient availability. The large gradient in CO 2 concentration between intercellular spaces and chloroplasts was another factor that explained a substantial part of the differences in PNUE max between Quercus and the other species that had smaller gradients. Stomatal and internal conductances for CO 2 explained most of the difference in PNUE max between Quercus and Populus at high nutrient availability for which these data were available.