Causes of decreased photosynthetic rate and metabolic capacity in water-deficient leaf cells: a critical evaluation of mechanisms and integration of processes.

By D. Lawlor, W. Tezara. Annals of Botany, 2009

821 citations recorded by the source corpus.

BACKGROUND Water deficit (WD) decreases photosynthetic rate (A) via decreased stomatal conductance to CO(2) (g(s)) and photosynthetic metabolic potential (A(pot)). The relative importance of g(s) and A(pot), and how they are affected by WD, are reviewed with respect to light intensity and to experimental approaches. SCOPE AND CONCLUSIONS With progressive WD, A decreases as g(s) falls. Under low light during growth and WD, A is stimulated by elevated CO(2), showing that metabolism (A(pot)) is not impaired, but at high light A is not stimulated, showing inhibition. At a given intercellular CO(2) concentration (C(i)) A decreases, showing impaired metabolism (A(pot)). The C(i) and probably chloroplast CO(2) concentration (C(c)), decreases and then increases, together with the equilibrium CO(2) concentration, with greater WD. Estimation of C(c) and internal (mesophyll) conductance (g(i)) is considered uncertain. Photosystem activity is unaffected until very severe WD, maintaining electron (e(-)) transport (ET) and reductant content. Low A, together with photorespiration (PR), which is maintained or decreased, provides a smaller sink for e(-)(,) causing over-energization of energy transduction. Despite increased non-photochemical quenching (NPQ), excess energy and e(-) result in generation of reactive oxygen species (ROS). Evidence is considered that ROS damages ATP synthase so that ATP content decreases progressively with WD. Decreased ATP limits RuBP production by the Calvin cycle and thus A(pot). Rubisco activity is unlikely to determine A(pot). Sucrose synthesis is limited by lack of substrate and impaired enzyme regulation. With WD, PR decreases relative to light respiration (R(L)), and mitochondria consume reductant and synthesise ATP. With progressing WD at low A, R(L) increases C(i) and C(c). This review emphasises the effects of light intensity, considers techniques, and develops a qualitative model of photosynthetic metabolism under WD that explains many observations: testable hypotheses are suggested.

Subfields: Global and Planetary Change, Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/75ffe595f663df64fa9626b5fe8ae607319359b4

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Citations in the corpus

Alternative Oxidase: A Mitochondrial Respiratory Pathway to Maintain Metabolic and Signaling Homeostasis during Abiotic and Biotic Stress in Plants (2013, background): “balance since photosynthetic rate is typically strongly impacted by drought, due to both stomatal and biochemical limitations, while respiratory rates are much less impacted [162–164].”
Response of Mediterranean Ornamental Plants to Drought Stress (2019, background): “Reacting with proteins and lipids, they modify structure, cellular metabolism, and, in particular, those that are linked to the photosynthetic process [79].”
Exogenous proline induces soluble sugar accumulation and alleviates drought stress effects on photosystem II functioning of Arabidopsis thaliana leaves (2011, background): “For this reason, photosynthesis responses to drought stress (DS) have been the subject of study and debate for decades, in particular, concerning which are the most limiting factors for photosynthesis under DS (Massacci and Loreto 2001; Galmés et al. 2007; Chaves et al. 2009; Flexas et al. 2009; Law”
Impact of Drought, Heat, and Their Combination on Chlorophyll Fluorescence and Yield of Wild Barley (Hordeum spontaneum) (2015, background): “, reduced activities of Calvin Benson cycle enzymes) occur under more severe drought stress conditions [9].”
Optimizing stomatal conductance for maximum carbon gain under water stress: a meta-analysis across plant functional types and climates (2011, neutral): “These so-called internal (met- abolic and diffusive) limitations become predominant rela- tive to stomatal limitation as water stress further increases (Du et al. 1996; Galmes, Medrano & Flexas 2007; Tezara, Driscoll & Lawlor 2008; Ghannoum 2009; Lawlor & Tezara 2009).”
Recent Advances in Photosynthesis Under Drought and Salinity (2011, background): “These physical characteristics change as a function of the shrinking response of tissues to drought (Lawlor and Tezara, 2009).”
Photosynthesis and drought: can we make metabolic connections from available data? (2011, background): “The magnitude of the latter is still under debate, with criticisms arising over methodological issues related to the estimation of the intercellular or the chloroplastic CO2 concentration (Bunce, 2009; Lawlor and Tezara, 2009).”
Growth enhancement and drought tolerance of hybrid poplar upon inoculation with endophyte consortia (2016, background): “[95] that the drought-adapted ecotypes nd cultivars of Andropogon gerardii had higher SPAD values in the rier habitats.”
Effect of corm size, water stress and cultivation conditions on photosynthesis and biomass partitioning during the vegetative growth of saffron (Crocus sativus L.) (2012, result): “Our results show a linear decrease in the photosynthetic rate with decreasing soil water potential, which is due to both stomatal and non-stomatal factors (Lawlor and Tezara, 2009).”