Graham Farquhar - Academia.edu (original) (raw)

Papers by Graham Farquhar

Crop Science, 1992

Breeding cultivars with improved water use efficiency (WUE = total biomass production/water use) ... more Breeding cultivars with improved water use efficiency (WUE = total biomass production/water use) has been limited by the lack of suitable screening criteria. Theory has predicted an association between WUE and Δ (leaf discrimination against 13C) that could be used in indirect selection for WUE in C3 plants. Several studies have provided empirical evidence supporting this theory but with some exceptions. Earlier studies showed genotypic and drought‐induced variation in Δ in cowpea (Vigna unguiculata (L.) Walp.) and expected associations with leaf gas exchange for drought‐induced effects but not for genotypic effects. Studies were conducted to evaluate directly the association between seasonal WUE and Δ in cowpea. Five contrasting genotypes and two isogenic lines were grown in the field either in pots or under natural soil conditions and subjected to well‐watered or drought treatments. Genotypic rankings for Δ in leaves were consistent in the wet and dry pot and natural soil condition...

Annals of Applied Biology, Apr 1, 1993

Crop growth, water-use efficiency and carbon isotope discrimination in groundnut (Amchis hypogaea... more Crop growth, water-use efficiency and carbon isotope discrimination in groundnut (Amchis hypogaea L.) genotypes under endsf season drought conditions*

Springer eBooks, 1989

ABSTRACT

Plant Physiology, Feb 1, 1990

Australian journal of agricultural research, 1991

Pod yield response of two spanish (McCubbin and Red Spanish) and two virginia (Virginia Bunch and... more Pod yield response of two spanish (McCubbin and Red Spanish) and two virginia (Virginia Bunch and Q18801) cultivars were compared under a range of irrigation treatments applied at different growth stages on a Xanthozem soil in a subtropical environment in southeast Queensland. Detailed growth and soil water use measurements were taken on a fully irrigated treatment and a treatment which received no rainfall after 83 days after planting (DAP). Soil water deficits occurring during the flowering to the start of pod growth phase (R/I) significantly reduced pod yields (range, 17-25%) relative to the well-watered control plots (I/I) for all cultivars. Where crops were irrigated until 8 3 DAP, then crop water deficits occurred throughout the pod growth phase (I/R), a significant cultivar by irrigation treatment interaction was observed for pod yield. The greatest reduction in yield occurred when severe stress occurred during the pod filling phase (Sh). Significant cultivar variation in pod yield was apparent. Differences in pod yield within this treatment were analysed in terms of a simple framework where pod yield is a function of transpired water (T) , transpiration efficiency (TE) and harvest index (H). Estimates of TE derived from measurements of carbon isotope discrimination in leaves indicated only small variation in TE, and suggest this trait contributed little to pod yield variation in the cultivars used in this experiment. Variation in pod yield among the four cultivars was largely a result of differences in harvest index characteristics.

Annual review of plant physiology and plant molecular biology, Jun 1, 1989

Plant Physiology, Dec 1, 1988

Cambridge University Press eBooks, Oct 27, 1989

Nature, Sep 1, 1993

LETTERS TO NATURE second step reaction of group I introns). We propose that the spliceosome gener... more LETTERS TO NATURE second step reaction of group I introns). We propose that the spliceosome generates a group I-like catalytic site to execute the second step of pre-mRNA splicing. D

Photosynthetic manipulation provides new opportunities for enhancing crop yield. However, underst... more Photosynthetic manipulation provides new opportunities for enhancing crop yield. However, understanding and quantifying effectively how the seasonal growth and yield dynamics of target crops might be affected over a wide range of environments is limited. Using a state-of-the-art cross-scale model we predicted crop-level impacts of a broad list of promising photosynthesis manipulation strategies for C3 wheat and C4 sorghum. The manipulation targets have varying effects on the enzyme-limited (Ac) and electron transport-limited (Aj) rates of photosynthesis. In the top decile of seasonal outcomes, yield gains with the list of manipulations were predicted to be modest, ranging between 0 and 8%, depending on the crop type and manipulation. To achieve the higher yield gains, large increases in both Ac and Aj are needed. This could likely be achieved by stacking Rubisco function and electron transport chain enhancements or installing a full CO2 concentrating system. However, photosynthetic ...

Nature Plants, 2020

Stable isotopes are commonly used to study the diffusion of CO inside photosynthetic tissues of p... more Stable isotopes are commonly used to study the diffusion of CO inside photosynthetic tissues of plants. The standard method to interpret the observed preference for the lighter carbon isotope in C 3 photosynthesis involves the model by Farquhar, O'Leary and Berry, which relates carbon isotope discrimination to physical and biochemical processes inside the leaf. However, under many conditions the model returns unreasonable results for mesophyll conductance to CO 2 diffusion (g m), especially when rates of photosynthesis are low. Here we re-derive the carbon isotope discrimination model using modified assumptions related to the isotope effect of mitochondrial respiration. In particular, we treat the carbon pool associated with respiration as separate from the pool of the primary assimilates. We experimentally test the model by comparing g m values measured with different CO 2 source gases varying in their isotopic composition and show that our new model returns matching g m values that are much more reasonable than those obtained with the old model. We use our results to discuss CO 2 diffusion properties inside the mesophyll.

Functional Plant Biology, 2019

Rice quantitative trait locus (QTL) qDTY12.1 is a major-effect drought yield QTL that was identif... more Rice quantitative trait locus (QTL) qDTY12.1 is a major-effect drought yield QTL that was identified from a cross of Vandana (recipient parent) and Way Rarem (donor parent) through breeding efforts to improve rice yield under upland drought stress conditions. The two main physiological effects previously observed to be related to the presence of qDTY12.1 were (i) increased lateral root growth, and (ii) increased transpiration efficiency. Since relatively more progress has thus far been made on characterising the lateral root growth response related to qDTY12.1, the present study focussed on characterising how qDTY12.1 confers higher transpiration efficiency under upland drought stress in the Vandana background. In a series of field experiments in which stomatal conductance was measured across different times of day in four qDTY12.1 near isogenic lines (NILs), the NILs and Way Rarem showed consistently higher stomatal conductance than Vandana under conditions of low vapour pressure d...

Functional Plant Biology, 2018

Photosynthetic manipulation is seen as a promising avenue for advancing field crop productivity. ... more Photosynthetic manipulation is seen as a promising avenue for advancing field crop productivity. However, progress is constrained by the lack of connection between leaf-level photosynthetic manipulation and crop performance. Here we report on the development of a model of diurnal canopy photosynthesis for well watered conditions by using biochemical models of C3 and C4 photosynthesis upscaled to the canopy level using the simple and robust sun–shade leaves representation of the canopy. The canopy model was integrated over the time course of the day for diurnal canopy photosynthesis simulation. Rationality analysis of the model showed that it simulated the expected responses in diurnal canopy photosynthesis and daily biomass accumulation to key environmental factors (i.e. radiation, temperature and CO2), canopy attributes (e.g. leaf area index and leaf angle) and canopy nitrogen status (i.e. specific leaf nitrogen and its profile through the canopy). This Diurnal Canopy Photosynthesi...

Plant Physiology, 1997

Cuticular properties affect the gas exchange of leaves, but little is known about how much CO2 an... more Cuticular properties affect the gas exchange of leaves, but little is known about how much CO2 and water vapor cross the cuticular barrier or whether low water potentials affect the process. Therefore, we measured the cuticular conductances for CO2 and water vapor in grape (Vitis vinifera L.) leaves having various water potentials. The lower leaf surface was sealed to force all gas exchange through the upper surface, which was stoma-free. In this condition both gases passed through the cuticle, and the CO2 conductance could be directly determined from the internal mole fraction of CO2 near the compensation point, the external mole fraction of CO2, and the CO2 flux. The cuticle allowed small amounts of CO2 and water vapor to pass through, indicating that gas exchange occurs in grape leaves no matter how tightly the stomata are closed. However, the CO2 conductance was only 5.7% of that for water vapor. This discrimination against CO2 markedly affected calculations of the mole fraction...

New Phytologist, 2015

Summary Leaf dark respiration (Rdark) is an important yet poorly quantified component of the glob... more Summary Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed‐effects models were used to disentangle sources of variation in Rdark. Area‐based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdark at a standard T (25°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher...

Progress in Photosynthesis Research, 1987

Jones (1) has discussed two main reasons for attempting to manipulate stornata by breeding. The f... more Jones (1) has discussed two main reasons for attempting to manipulate stornata by breeding. The first was to maximise productivity and hence yield, by increasing rates of assimilation of CO2. An increase in stomatal conductance would be expected to achieve this in C3 species by increasing the partial pressure of CO2 within the leaf, p., which would be useful in conditions where water supply is not limiting. The second was to improve drought tolerance. A decreased stomatal conductance can aid in this direction, but at some expense to yield potential (yield in well-watered conditions).

Historical Records of Australian Science, 2020

Ralph Slatyer (16 April 1929–26 July 2012) had a distinguished career in the Commonwealth Scienti... more Ralph Slatyer (16 April 1929–26 July 2012) had a distinguished career in the Commonwealth Scientific and Industrial Research Organisation and the Australian National University, in plant-water relations and plant succession, leading the development of physiological plant ecology. He was the founding Professor of Environmental Biology at the Research School of Biological Sciences, at the Australian National University and then Director of the Research School of Biological Sciences, 1984–9. He was Australian Ambassador to United Nations Educational and Scientific Cultural Organisation (1978–81), and as Australia’s first Chief Scientist (1989–92), he set up the Cooperative Research Centres.

Nature Plants, 2021

In the version of this Article originally published, there were errors in equations (17) and (18)... more In the version of this Article originally published, there were errors in equations (17) and (18), and in Supplementary Note 7. In equation (17), both instances of 'g cw-ab γ' should have been 'g cw-ad ' , and both instances of 'g cw-ab ' should have been 'g cw-ad γ'; that is, the equation should have read:

Nature Plants, 2020

Tight coordination in the photosynthetic, gas exchange and water supply capacities of leaves is a... more Tight coordination in the photosynthetic, gas exchange and water supply capacities of leaves is a globally conserved trend across land plants. Strong selective constraints on leaf carbon gain create the opportunity to use quantitative optimisation theory to understand the connected evolution of leaf photosynthesis and water relations. We developed an analytical optimisation model that maximises the long-term rate of leaf carbon gain, given carbon costs in building and maintaining stomata, leaf hydraulics and osmotic pressure. Our model demonstrates that selection for optimal gain should drive coordination between key photosynthetic, gas exchange and water relations traits. It also provides predictions of adaptation to drought and the relative costs of key leaf functional traits. Our results show that optimisation in terms of carbon gain given carbon costs of physiological traits successfully unites leaf photosynthesis and water relations and provides a quantitative framework to consider leaf functional evolution and adaptation. Farquhar, G. D. Models of integrated photosynthesis of cells and leaves.

Crop Science, 1992

Breeding cultivars with improved water use efficiency (WUE = total biomass production/water use) ... more Breeding cultivars with improved water use efficiency (WUE = total biomass production/water use) has been limited by the lack of suitable screening criteria. Theory has predicted an association between WUE and Δ (leaf discrimination against 13C) that could be used in indirect selection for WUE in C3 plants. Several studies have provided empirical evidence supporting this theory but with some exceptions. Earlier studies showed genotypic and drought‐induced variation in Δ in cowpea (Vigna unguiculata (L.) Walp.) and expected associations with leaf gas exchange for drought‐induced effects but not for genotypic effects. Studies were conducted to evaluate directly the association between seasonal WUE and Δ in cowpea. Five contrasting genotypes and two isogenic lines were grown in the field either in pots or under natural soil conditions and subjected to well‐watered or drought treatments. Genotypic rankings for Δ in leaves were consistent in the wet and dry pot and natural soil condition...

Annals of Applied Biology, Apr 1, 1993

Crop growth, water-use efficiency and carbon isotope discrimination in groundnut (Amchis hypogaea... more Crop growth, water-use efficiency and carbon isotope discrimination in groundnut (Amchis hypogaea L.) genotypes under endsf season drought conditions*

Springer eBooks, 1989

ABSTRACT

Plant Physiology, Feb 1, 1990

Australian journal of agricultural research, 1991

Pod yield response of two spanish (McCubbin and Red Spanish) and two virginia (Virginia Bunch and... more Pod yield response of two spanish (McCubbin and Red Spanish) and two virginia (Virginia Bunch and Q18801) cultivars were compared under a range of irrigation treatments applied at different growth stages on a Xanthozem soil in a subtropical environment in southeast Queensland. Detailed growth and soil water use measurements were taken on a fully irrigated treatment and a treatment which received no rainfall after 83 days after planting (DAP). Soil water deficits occurring during the flowering to the start of pod growth phase (R/I) significantly reduced pod yields (range, 17-25%) relative to the well-watered control plots (I/I) for all cultivars. Where crops were irrigated until 8 3 DAP, then crop water deficits occurred throughout the pod growth phase (I/R), a significant cultivar by irrigation treatment interaction was observed for pod yield. The greatest reduction in yield occurred when severe stress occurred during the pod filling phase (Sh). Significant cultivar variation in pod yield was apparent. Differences in pod yield within this treatment were analysed in terms of a simple framework where pod yield is a function of transpired water (T) , transpiration efficiency (TE) and harvest index (H). Estimates of TE derived from measurements of carbon isotope discrimination in leaves indicated only small variation in TE, and suggest this trait contributed little to pod yield variation in the cultivars used in this experiment. Variation in pod yield among the four cultivars was largely a result of differences in harvest index characteristics.

Annual review of plant physiology and plant molecular biology, Jun 1, 1989

Plant Physiology, Dec 1, 1988

Cambridge University Press eBooks, Oct 27, 1989

Nature, Sep 1, 1993

LETTERS TO NATURE second step reaction of group I introns). We propose that the spliceosome gener... more LETTERS TO NATURE second step reaction of group I introns). We propose that the spliceosome generates a group I-like catalytic site to execute the second step of pre-mRNA splicing. D

Photosynthetic manipulation provides new opportunities for enhancing crop yield. However, underst... more Photosynthetic manipulation provides new opportunities for enhancing crop yield. However, understanding and quantifying effectively how the seasonal growth and yield dynamics of target crops might be affected over a wide range of environments is limited. Using a state-of-the-art cross-scale model we predicted crop-level impacts of a broad list of promising photosynthesis manipulation strategies for C3 wheat and C4 sorghum. The manipulation targets have varying effects on the enzyme-limited (Ac) and electron transport-limited (Aj) rates of photosynthesis. In the top decile of seasonal outcomes, yield gains with the list of manipulations were predicted to be modest, ranging between 0 and 8%, depending on the crop type and manipulation. To achieve the higher yield gains, large increases in both Ac and Aj are needed. This could likely be achieved by stacking Rubisco function and electron transport chain enhancements or installing a full CO2 concentrating system. However, photosynthetic ...

Nature Plants, 2020

Stable isotopes are commonly used to study the diffusion of CO inside photosynthetic tissues of p... more Stable isotopes are commonly used to study the diffusion of CO inside photosynthetic tissues of plants. The standard method to interpret the observed preference for the lighter carbon isotope in C 3 photosynthesis involves the model by Farquhar, O'Leary and Berry, which relates carbon isotope discrimination to physical and biochemical processes inside the leaf. However, under many conditions the model returns unreasonable results for mesophyll conductance to CO 2 diffusion (g m), especially when rates of photosynthesis are low. Here we re-derive the carbon isotope discrimination model using modified assumptions related to the isotope effect of mitochondrial respiration. In particular, we treat the carbon pool associated with respiration as separate from the pool of the primary assimilates. We experimentally test the model by comparing g m values measured with different CO 2 source gases varying in their isotopic composition and show that our new model returns matching g m values that are much more reasonable than those obtained with the old model. We use our results to discuss CO 2 diffusion properties inside the mesophyll.

Functional Plant Biology, 2019

Rice quantitative trait locus (QTL) qDTY12.1 is a major-effect drought yield QTL that was identif... more Rice quantitative trait locus (QTL) qDTY12.1 is a major-effect drought yield QTL that was identified from a cross of Vandana (recipient parent) and Way Rarem (donor parent) through breeding efforts to improve rice yield under upland drought stress conditions. The two main physiological effects previously observed to be related to the presence of qDTY12.1 were (i) increased lateral root growth, and (ii) increased transpiration efficiency. Since relatively more progress has thus far been made on characterising the lateral root growth response related to qDTY12.1, the present study focussed on characterising how qDTY12.1 confers higher transpiration efficiency under upland drought stress in the Vandana background. In a series of field experiments in which stomatal conductance was measured across different times of day in four qDTY12.1 near isogenic lines (NILs), the NILs and Way Rarem showed consistently higher stomatal conductance than Vandana under conditions of low vapour pressure d...

Functional Plant Biology, 2018

Photosynthetic manipulation is seen as a promising avenue for advancing field crop productivity. ... more Photosynthetic manipulation is seen as a promising avenue for advancing field crop productivity. However, progress is constrained by the lack of connection between leaf-level photosynthetic manipulation and crop performance. Here we report on the development of a model of diurnal canopy photosynthesis for well watered conditions by using biochemical models of C3 and C4 photosynthesis upscaled to the canopy level using the simple and robust sun–shade leaves representation of the canopy. The canopy model was integrated over the time course of the day for diurnal canopy photosynthesis simulation. Rationality analysis of the model showed that it simulated the expected responses in diurnal canopy photosynthesis and daily biomass accumulation to key environmental factors (i.e. radiation, temperature and CO2), canopy attributes (e.g. leaf area index and leaf angle) and canopy nitrogen status (i.e. specific leaf nitrogen and its profile through the canopy). This Diurnal Canopy Photosynthesi...

Plant Physiology, 1997

Cuticular properties affect the gas exchange of leaves, but little is known about how much CO2 an... more Cuticular properties affect the gas exchange of leaves, but little is known about how much CO2 and water vapor cross the cuticular barrier or whether low water potentials affect the process. Therefore, we measured the cuticular conductances for CO2 and water vapor in grape (Vitis vinifera L.) leaves having various water potentials. The lower leaf surface was sealed to force all gas exchange through the upper surface, which was stoma-free. In this condition both gases passed through the cuticle, and the CO2 conductance could be directly determined from the internal mole fraction of CO2 near the compensation point, the external mole fraction of CO2, and the CO2 flux. The cuticle allowed small amounts of CO2 and water vapor to pass through, indicating that gas exchange occurs in grape leaves no matter how tightly the stomata are closed. However, the CO2 conductance was only 5.7% of that for water vapor. This discrimination against CO2 markedly affected calculations of the mole fraction...

New Phytologist, 2015

Summary Leaf dark respiration (Rdark) is an important yet poorly quantified component of the glob... more Summary Leaf dark respiration (Rdark) is an important yet poorly quantified component of the global carbon cycle. Given this, we analyzed a new global database of Rdark and associated leaf traits. Data for 899 species were compiled from 100 sites (from the Arctic to the tropics). Several woody and nonwoody plant functional types (PFTs) were represented. Mixed‐effects models were used to disentangle sources of variation in Rdark. Area‐based Rdark at the prevailing average daily growth temperature (T) of each site increased only twofold from the Arctic to the tropics, despite a 20°C increase in growing T (8–28°C). By contrast, Rdark at a standard T (25°C, Rdark25) was threefold higher in the Arctic than in the tropics, and twofold higher at arid than at mesic sites. Species and PFTs at cold sites exhibited higher Rdark25 at a given photosynthetic capacity (Vcmax25) or leaf nitrogen concentration ([N]) than species at warmer sites. Rdark25 values at any given Vcmax25 or [N] were higher...

Progress in Photosynthesis Research, 1987

Jones (1) has discussed two main reasons for attempting to manipulate stornata by breeding. The f... more Jones (1) has discussed two main reasons for attempting to manipulate stornata by breeding. The first was to maximise productivity and hence yield, by increasing rates of assimilation of CO2. An increase in stomatal conductance would be expected to achieve this in C3 species by increasing the partial pressure of CO2 within the leaf, p., which would be useful in conditions where water supply is not limiting. The second was to improve drought tolerance. A decreased stomatal conductance can aid in this direction, but at some expense to yield potential (yield in well-watered conditions).

Historical Records of Australian Science, 2020

Ralph Slatyer (16 April 1929–26 July 2012) had a distinguished career in the Commonwealth Scienti... more Ralph Slatyer (16 April 1929–26 July 2012) had a distinguished career in the Commonwealth Scientific and Industrial Research Organisation and the Australian National University, in plant-water relations and plant succession, leading the development of physiological plant ecology. He was the founding Professor of Environmental Biology at the Research School of Biological Sciences, at the Australian National University and then Director of the Research School of Biological Sciences, 1984–9. He was Australian Ambassador to United Nations Educational and Scientific Cultural Organisation (1978–81), and as Australia’s first Chief Scientist (1989–92), he set up the Cooperative Research Centres.

Nature Plants, 2021

In the version of this Article originally published, there were errors in equations (17) and (18)... more In the version of this Article originally published, there were errors in equations (17) and (18), and in Supplementary Note 7. In equation (17), both instances of 'g cw-ab γ' should have been 'g cw-ad ' , and both instances of 'g cw-ab ' should have been 'g cw-ad γ'; that is, the equation should have read:

Nature Plants, 2020

Tight coordination in the photosynthetic, gas exchange and water supply capacities of leaves is a... more Tight coordination in the photosynthetic, gas exchange and water supply capacities of leaves is a globally conserved trend across land plants. Strong selective constraints on leaf carbon gain create the opportunity to use quantitative optimisation theory to understand the connected evolution of leaf photosynthesis and water relations. We developed an analytical optimisation model that maximises the long-term rate of leaf carbon gain, given carbon costs in building and maintaining stomata, leaf hydraulics and osmotic pressure. Our model demonstrates that selection for optimal gain should drive coordination between key photosynthetic, gas exchange and water relations traits. It also provides predictions of adaptation to drought and the relative costs of key leaf functional traits. Our results show that optimisation in terms of carbon gain given carbon costs of physiological traits successfully unites leaf photosynthesis and water relations and provides a quantitative framework to consider leaf functional evolution and adaptation. Farquhar, G. D. Models of integrated photosynthesis of cells and leaves.