The impact of stomatal kinetics on diurnal photosynthesis and water use efficiency under fluctuating light

AbstractDynamic light conditions require continuous adjustments of stomatal aperture. As stomatal conductance (gs) kinetics are a magnitude slower than photosynthesis (A), they are hypothesized to be key to plant productivity and water use efficiency. Using step-changes in light intensity, we studied the diversity of light-induced gs kinetics in relation to stomatal anatomy in five banana genotypes (Musa spp.) and modelled the impact on A and intrinsic water use efficiency (iWUE). Banana generally exhibited a strong limitation of A by gs, indicating a priority for water saving. Significant genotypic differences in gs kinetics and gs-based limitations of A were observed. For two contrasting genotypes the impact of differential gs kinetics on A and iWUE was further investigated under realistic diurnally fluctuating light conditions and at whole-plant level. Genotype-specific stomatal kinetics observed at the leaf level were corroborated at whole-plant level, suggesting that despite differences in gs control at different locations in the leaf and across leaves, genotype-specific responses are still maintained. However, under diurnally fluctuating light conditions gs speediness had only a momentary impact on the diurnal iWUE and carbon gain. During the afternoon there was a setback in kinetics: the absolute gs and the gs responses to light were damped, strongly limiting A and the diurnal iWUE. We conclude that the impact of the differential gs kinetics on the limitation of A was dependent on the target light intensity, the magnitude of change, the gs prior to the intensity change and particularly the time of the day.One sentence summaryGenotype-specific stomatal rapidity is for the first time validated at whole-plant level, but under fluctuating light the impact of stomatal dynamics depends on other factors like the time of the day.

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Water-use efficiency in grapevine cultivars grown under controlled conditions: effects of water stress at the leaf and whole-plant level

Australian Journal of Grape and Wine Research ◽

10.1111/j.1755-0238.2012.00184.x ◽

2012 ◽

Vol 18 (2) ◽

pp. 164-172 ◽

Cited By ~ 71

Author(s):

M. TOMÁS ◽

H. MEDRANO ◽

A. POU ◽

J.M. ESCALONA ◽

S. MARTORELL ◽

...

Keyword(s):

Water Stress ◽

Water Use Efficiency ◽

Water Use ◽

Controlled Conditions ◽

Whole Plant ◽

Use Efficiency ◽

Plant Level

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The Intra-Annual Intrinsic Water Use Efficiency Dynamics Based on an Improved Model

10.21203/rs.3.rs-1060472/v1 ◽

2021 ◽

Author(s):

Xiaojin Bing ◽

Keyan Fang ◽

Xiaoying Gong ◽

Wenzhi Wang ◽

Chenxi Xu ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Pinus Massoniana ◽

C3 Plants ◽

Mountain Area ◽

Southeast China ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

Improved Model ◽

The Impact

Abstract The carbon isotope fractionation value (Δ) has been widely used to infer the intrinsic water use efficiency (iWUE) of C3 plants. Currently, the most commonly used iWUE method (expressed as iWUE tra ) in tree rings assumes that the mesophyll conductance in plants is infinite. However, many observation-based studies have pointed out that such an assumption leads to overestimating the impact of carbon dioxide (CO 2 ) on intrinsic water use efficiency in plants. In this study, a constant g s /g m ratio (0.79) was introduced for calculating iWUE (expressedas iWUE mes ). We applied this iWUE mes model to our newly developed intra-annual (10 samples per ring) Δ 13 C chronology of Cryptomeria fortunei tree for 1965–2017 at Gu Mountain Area and our annual Δ 13 C chronology of Pinus massoniana tree for 1865–2014 at Niumulin Natural Reserve in southeast China. Using dendrochronology techniques, our analysis revealed that the current iWUE tra model overestimates the iWUE values by approximately 2 times and that the iWUE value of trees inferred from iWUE mes modelling decreased significantly in summer-autumn time, which may indicate that alternative factors play a role in limiting the degree of iWUE improvement under the drought-stressed forest in southeast China.

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Drought-induced mortality selectively affects Scots pine trees that show limited intrinsic water-use efficiency responsiveness to raising atmospheric CO2

Functional Plant Biology ◽

10.1071/fp13067 ◽

2014 ◽

Vol 41 (3) ◽

pp. 244 ◽

Cited By ~ 24

Author(s):

Ana-Maria Hereş ◽

Jordi Voltas ◽

Bernat Claramunt López ◽

Jordi Martínez-Vilalta

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Tree Mortality ◽

Intercellular Co2 Concentration ◽

Co2 Concentration ◽

Atmospheric Co2 ◽

Growth Enhancement ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

The Impact

Widespread drought-induced tree mortality has been documented around the world, and could increase in frequency and intensity under warmer and drier conditions. Ecophysiological differences between dying and surviving trees might underlie predispositions to mortality, but are poorly documented. Here we report a study of Scots pines (Pinus sylvestris L.) from two sites located in north-eastern Iberian Peninsula where drought-associated mortality episodes were registered during the last few decades. Time trends of discrimination against 13C (Δ13C) and intrinsic water-use efficiency (WUEi) in tree rings at an annual resolution and for a 34 year period were used to compare co-occurring now-dead and surviving pines. Results indicate that both surviving and now-dead pines significantly increased their WUEi over time, although this increase was significantly lower for now-dead individuals. These differential WUEi trends corresponded to different scenarios describing how plant gas exchange responds to increasing atmospheric CO2 (Ca): the estimated intercellular CO2 concentration was nearly constant in surviving pines but tended to increase proportionally to Ca in now-dead trees. Concurrently, the WUEi increase was not paralleled by a growth enhancement, regardless of tree state, suggesting that in water-limited areas like the Mediterranean, it cannot overcome the impact of an increasingly warmer and drier climate on tree growth.

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Drivers of Natural Variation in Water-Use Efficiency Under Fluctuating Light Are Promising Targets for Improvement in Sorghum

Frontiers in Plant Science ◽

10.3389/fpls.2021.627432 ◽

2021 ◽

Vol 12 ◽

Author(s):

Charles P. Pignon ◽

Andrew D. B. Leakey ◽

Stephen P. Long ◽

Johannes Kromdijk

Keyword(s):

Steady State ◽

Stomatal Conductance ◽

Water Use Efficiency ◽

Water Use ◽

Plant Performance ◽

Fluctuating Light ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

Natural Diversity ◽

Highly Correlated

Improving leaf intrinsic water-use efficiency (iWUE), the ratio of photosynthetic CO2 assimilation to stomatal conductance, could decrease crop freshwater consumption. iWUE has primarily been studied under steady-state light, but light in crop stands rapidly fluctuates. Leaf responses to these fluctuations substantially affect overall plant performance. Notably, photosynthesis responds faster than stomata to decreases in light intensity: this desynchronization results in substantial loss of iWUE. Traits that could improve iWUE under fluctuating light, such as faster stomatal movement to better synchronize stomata with photosynthesis, show significant natural diversity in C3 species. However, C4 crops have been less closely investigated. Additionally, while modification of photosynthetic or stomatal traits independent of one another will theoretically have a proportionate effect on iWUE, in reality these traits are inter-dependent. It is unclear how interactions between photosynthesis and stomata affect natural diversity in iWUE, and whether some traits are more tractable drivers to improve iWUE. Here, measurements of photosynthesis, stomatal conductance and iWUE under steady-state and fluctuating light, along with stomatal patterning, were obtained in 18 field-grown accessions of the C4 crop sorghum. These traits showed significant natural diversity but were highly correlated, with important implications for improvement of iWUE. Some features, such as gradual responses of photosynthesis to decreases in light, appeared promising for improvement of iWUE. Other traits showed tradeoffs that negated benefits to iWUE, e.g., accessions with faster stomatal responses to decreases in light, expected to benefit iWUE, also displayed more abrupt losses in photosynthesis, resulting in overall lower iWUE. Genetic engineering might be needed to break these natural tradeoffs and achieve optimal trait combinations, e.g., leaves with fewer, smaller stomata, more sensitive to changes in photosynthesis. Traits describing iWUE at steady-state, and the change in iWUE following decreases in light, were important contributors to overall iWUE under fluctuating light.

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Rising CO2 drives divergence in water use efficiency of evergreen and deciduous plants

Science Advances ◽

10.1126/sciadv.aax7906 ◽

2019 ◽

Vol 5 (12) ◽

pp. eaax7906 ◽

Cited By ~ 7

Author(s):

Wuu Kuang Soh ◽

Charilaos Yiotis ◽

Michelle Murray ◽

Andrew Parnell ◽

Ian J. Wright ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Boreal Forests ◽

Leaf Mass Per Area ◽

Mean Annual Temperature ◽

Evergreen Species ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency ◽

The Difference ◽

The Impact

Intrinsic water use efficiency (iWUE), defined as the ratio of photosynthesis to stomatal conductance, is a key variable in plant physiology and ecology. Yet, how rising atmospheric CO2 concentration affects iWUE at broad species and ecosystem scales is poorly understood. In a field-based study of 244 woody angiosperm species across eight biomes over the past 25 years of increasing atmospheric CO2 (~45 ppm), we show that iWUE in evergreen species has increased more rapidly than in deciduous species. Specifically, the difference in iWUE gain between evergreen and deciduous taxa diverges along a mean annual temperature gradient from tropical to boreal forests and follows similar observed trends in leaf functional traits such as leaf mass per area. Synthesis of multiple lines of evidence supports our findings. This study provides timely insights into the impact of Anthropocene climate change on forest ecosystems and will aid the development of next-generation trait-based vegetation models.

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