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Modelling net photosynthetic rate of field‐grown cocksfoot leaves under different nitrogen, water and temperature regimes
Author(s) -
Peri P. L.,
Moot D. J.,
McNeil D. L.,
Varella A. C.,
Lucas R. J.
Publication year - 2002
Publication title -
grass and forage science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.716
H-Index - 56
eISSN - 1365-2494
pISSN - 0142-5242
DOI - 10.1046/j.1365-2494.2002.00302.x
Subject(s) - zoology , nitrogen , photosynthesis , stomatal conductance , limiting , biology , botany , chemistry , mechanical engineering , organic chemistry , engineering
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 CO 2 m –2 s −1 in non‐limited conditions, which was defined as the standardized Pmax value dimensionless ( Pmax s =1). Pmax s increased 0·058 units per °C from 10°C to the optimum range (19–23°C) ( Pmax s =1) and then declined 0·077 units of Pmax s per °C from 23 to 31°C. Pmax s =1 was also measured from 59 to 52 g N kg −1 dry matter (DM) foliage N. Pmax s 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 Pmax s per 10 g N kg −1 DM from 26 to 15 g N kg −1 DM. For predawn leaf water potential (ψ lp ), Pmax s =1 was measured from −0·1 to −1·2 bar but declined linearly at a rate of 0·078 units per bar of ψ lp 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 Pmax s .