ISSN:
1365-2494
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
A simple multiplicative model using temperature, foliage nitrogen (N) concentration and water status was developed to predict the maximum photosynthetic rate (Pmax) of field-grown cocksfoot (Dactylis glomerata L.) leaves when none, one, two or all the factors were limiting. The highest Pmax was 27·4 μmol CO2 m–2 s−1 in non-limited conditions, which was defined as the standardized Pmax value dimensionless (Pmaxs=1). Pmaxs increased 0·058 units per °C from 10°C to the optimum range (19–23°C) (Pmaxs=1) and then declined 0·077 units of Pmaxs per °C from 23 to 31°C. Pmaxs=1 was also measured from 59 to 52 g N kg−1 dry matter (DM) foliage N. Pmaxs then decreased at the rate of 0·115 units per 10 g N kg−1 DM from 52 to 26 g N kg−1 DM, and 0·409 units of Pmaxs per 10 g N kg−1 DM from 26 to 15 g N kg−1 DM. For predawn leaf water potential (ψlp), Pmaxs=1 was measured from −0·1 to −1·2 bar but declined linearly at a rate of 0·078 units per bar of ψlp from −1·2 to −14·0 bar because of a linear decrease in stomatal conductance. An interaction between low N content (≤20 g N kg−1 DM) and high temperature (〉23°C) was also detected. Together, this multiplicative model accounted for 0·82 of the variation in Pmaxs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1046/j.1365-2494.2002.00302.x
