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Modelling net photosynthesis rate of field grown cocksfoot leaves under different nitrogen, water and temperature regimes
journal contribution
posted on 2023-05-16, 18:37 authored by Peri, PL, Moot, DJ, McNeil, DL, Varella, AC, Lucas, RJA 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.
History
Publication title
Grass and Forage ScienceVolume
57Pagination
61-71ISSN
0142-5242Department/School
Tasmanian Institute of Agriculture (TIA)Publisher
Blackwell Publishing LtdPlace of publication
United KingdomRepository Status
- Restricted