Photosynthetic Capacity and Photosynthetic Nutrient-Use Efficiency of Rhododendron lapponicum Leaves as Related to Leaf Nutrient Status, Leaf Age and Branch Reproductive Status

Possible determinants of the area-based light-saturated photosynthetic rate (P s , μmol CO 2 m -2 s -1 ) for Rhododendron lapponicum from a subarctic site in northern Sweden were studied. P s was determined in the laboratory on detached branches, under non-limiting water conditions, constant light and temperature, and related to leaf nitrogen and phosphorus contents, leaf age (current-year and 1 -year-old leaves) and branch reproductive status (non-reproductive, 1 year before seed production, seed producing and 1 year after seed production). P s increased with increasing leaf nitrogen content and nitrogen was the most important determinant of P s explaining 45% of the total variation (...)