kunstler
commented
6 years ago Link between Vcmax and Jmax The hypothesis of a coordination between Calvin-Benson cycle limited rate of assimilation and electron transport-limited rate of assimilation, leading to the assumption of a correlation between Vcmax and Jmax. Different model to link them have been proposed.
- according to Medlyn et al. 2002 Jmax = 1.67 Vcmax
- in Walker, A. P. et al. 2014. The relationship of leaf photosynthetic traits - Vcmax and Jmax - to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modelling study. - Ecology and Evolution 4: 3218–3235. It is a power function exp(1.01)*V^0.89
- in Try data from Kattge et al. 2011 exp(1.669)*V^0.75,
- in Wullschleger 1993 exp(1.425)*V^0.837
V <- 5:200
plot(V, V*1.67, type = "l", xlab = "Vcmax", ylab = "Jmax")
lines(V, exp(1.01)*V^0.89, lty = 2)
lines(V, exp(1.669)*V^0.75, lty = 3)
lines(V, exp(1.425)*V^0.837, lty = 4)
legend("topleft", legend = c("Medlyn", "Walker", "Kattge", "Wullschleger"),
lty = 1:4)
The slope of Jmax vs Vcamx (in log log) affect the light level at which photosynthesis become RuBisCO limited. A shallower slope shifts the light level to higher light value and a steeper slope to a lower light value. This will thus affect shade tolerance.
The link between Vcmax and Jmax might, however, be more complex and depend on the light level and leaf P. According to Walker et al. 2014 the effect of SLA and leaf P are however relatively small. So this is ok to use only Jmax in function of Vcmax.
Vcmax vs Narea The photosynthetic rate should scale positively with leaf Nitrogen (N) because of the large amount of N invested in RuBisCO. Several relationships have been proposed to link Vcmax and leaf N.
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Sakschewski et al. 2014 Vcmax = 31.62Narea^0.801 but UNIT CONVERSION of g per m2 to kg per m2 1000^0.801
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ln(Vcmax) = 3.946 + 0.921 log(N) + 0.121 log(P) + 0.281log(N)log(P), Walker et al. 2014. To get a function of only N we can take the mean leaf P (in TRY mean leaf P per area is 0.104 g m-2, in Walker et al. 2014 data this is 0.135)
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Kattge et al. 2009. Vcmax = a + b * N with a different value per Biomes estimated either with Vcmax only or also constrained by Amax. Parameters from Kattge:
#With only Vcmax a1 <- c(1.99, 6.35, 5.4, 34.05, 4.61) b1 <- c(10.71, 25.88, 30.38, 9.71, 30.20) # when estimation use also Amax not only Vcmax a2 <- c(8.9, 4.19, 5.73, 6.32, 14.71) b2 <- c(9.30, 26.19, 26.81, 18.15, 23.15) names(a1) <- names(b1) <- names(a2) <- names(b2) <-c("Tropical_Trees_Oxisols", "Tropical_Trees_NonOxisols", "Temperate_Trees", "Coniferous_Trees", "Shrubs") -
Walker et al. 2017 explore several alternative model for Vcmax:a modificytion of Walker et al. is Vcmax = exp(3.712)*N^0.650
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Domingues et al. 2011 Vcmax = 10^1.57*N^0.55 # Appendix C Table A2
Narea <- seq(0.1, 10, length.out = 100)
plot(Narea, 31.62*Narea^0.801, type = "l", xlab = "Narea (g m-2)",
ylab = "Vcmax")
lines(Narea, exp(3.712)*Narea^0.650, lty = 2)
lines(Narea, 10^1.57*Narea^0.55, lty = 3)
lines(Narea, mean(a1) + Narea*mean(b1), lty = 4 , col = 2)
lines(Narea, mean(a2) + Narea*mean(b2), lty = 4 , col = 3)
legend("topleft", legend = c("Sakschewski-TRY", "Walker2017",
"Domingues2011", "Kattge2009_V_meanPFT",
"Kattge2009_VA_meanPFT"),
lty = c(1:4,4), col = c(1,1,1,2,3))
Curves for all PFT use in Kattge et al. 2009:
plot(Narea, 31.62*Narea^0.801, type = "l", lty = 0, xlab = "Narea (g m-2)",
ylab = "Vcmax")
for (i in 1:5){
lines(Narea, a1[i] + Narea*b1[i], lty = 1 , col = i+1)
lines(Narea, a2[i] + Narea*b2[i], lty = 2 , col = i+1)
}
legend("topleft", legend = names(a1),
lty = 1, col = 2:6)
Other traits such as leaf P and SLA could also influence Vcmax (Domingues et al. 2010, Walker et al. 2014). SLA have little effect on the link between Vcmax and leaf N. Leaf P have little direct effect on Vcmax but an important interaction with leaf N: at low leaf P the slope of Vcmax vs leaf N is shallow but at high leaf P this slope is steep (see Walker et al. 2014). See figure from Walker et al. 2014
It is also possible to use another approach where both Jmax is a function of traits rather than having Jmax a function of Vcmax (Domingues et al. 2010, Walker et al. 2014).
References:
- Domingues, T. F. et al. 2010. Co-limitation of photosynthetic capacity by nitrogen and phosphorus in West Africa woodlands: Nutrients constraints on photosynthesis in African woodlands. - Plant, Cell & Environment 33: 959–980.
- Kattge, J. et al. 2009. Quantifying photosynthetic capacity and its relationship to leaf nitrogen content for global-scale terrestrial biosphere models. - Global Change Biology 15: 976–991.
- Kattge, J. et al. 2011. TRY - a global database of plant traits. - Global Change Biology 17: 2905–2935.
- Medlyn, B. E. et al. 2002. Temperature response of parameters of a biochemically based model of photosynthesis. II. A review of experimental data. - Plant, Cell & Environment 25: 1167–1179.
- Sakschewski, B. et al. 2015. Leaf and stem economics spectra drive diversity of functional plant traits in a dynamic global vegetation model. - Global Change Biology 21: 2711–2725.
- Walker, A. P. et al. 2014. The relationship of leaf photosynthetic traits - Vcmax and Jmax - to leaf nitrogen, leaf phosphorus, and specific leaf area: a meta-analysis and modelling study. - Ecology and Evolution 4: 3218–3235.
- Walker, A. P. et al. 2017. The impact of alternative trait-scaling hypotheses for the maximum photosynthetic carboxylation rate ( Vcmax ) on global gross primary production. - New Phytologist 215: 1370–1386.
- WULLSCHLEGER, S. D. 1993. Biochemical Limitations to Carbon Assimilation in C3 Plants—A Retrospective Analysis of the A/Ci Curves from 109 Species. - Journal of Experimental Botany 44: 907–920.
So far I'm using Sakschewski, et al. 2015 to link Vcmax to Leaf N but there is other ref. I need to write done all possibility. Then for the Link between Jmax and Vcmax I'm using Medlyn et al. 2002 (1.67) but othe roption exist as well.
same as https://github.com/traitecoevo/trait_gradients/issues/33