Incontinence in aging leaves: deteriorating water relations with leaf age in Agastachys odorata (Proteaceae), a shrub with very long-lived leaves

2007 ◽  
Vol 34 (10) ◽  
pp. 918 ◽  
Author(s):  
Gregory J. Jordan ◽  
Timothy J. Brodribb
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Leaf Age ◽  
Carbon Assimilation ◽  
Leaf Damage ◽  
Evergreen Species ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Cuticle Thickness

This paper examines physiological characteristics of the leaves of Agastachys odorata R.Br., a wet-climate sclerophyllous shrub with very long-lived leaves. It addresses the hypothesis that cuticles become leakier to water vapour as leaves age. Astomatous cuticular conductance, whole-leaf minimum epidermal conductance, leaf damage and accumulation of epiphylls all increased several-fold with leaf age from first year growth to 10 years of age. Maximum carbon assimilation peaked 1 year after full leaf expansion, then declined. Intrinsic water use efficiency was highest in mid-aged leaves and declined markedly in the oldest leaves. Stomatal density, stomatal size and cuticle thickness did not vary significantly among ages. The older leaves were less effective at controlling water loss, resulting in decreases in water use efficiency. A differential increase in the conductance of the stomatal surface of the leaves relative to astomatous surface suggested that stomatal leakiness was significant in leaves over five years old. Although data for other species is ambiguous, the deterioration in A. odorata appears to be consistent with changes in the oldest leaves of other species. Thus, decreasing ability to use water efficiently appears to be a consequence of accumulated damage and may contribute to the need for leaf senescence in evergreen species with little self shading.

Variation in mesophyll conductance among Australian wheat genotypes

2014 ◽  
Vol 41 (6) ◽  
pp. 568 ◽  
Author(s):  
Eisrat Jahan ◽  
Jeffrey S. Amthor ◽  
Graham D. Farquhar ◽  
Richard Trethowan ◽  
Margaret M. Barbour
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Photosynthetic Rate ◽  
Genotypic Variation ◽  
Leaf Age ◽  
Triticum Aestivum L ◽  
Mesophyll Conductance ◽  
Wheat Genotypes ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

CO2 diffusion from substomatal intercellular cavities to sites of carboxylation in chloroplasts (mesophyll conductance; gm) limits photosynthetic rate and influences leaf intrinsic water-use efficiency (A/gsw). We investigated genotypic variability of gm and effects of gm on A/gsw among eleven wheat (Triticum aestivum L.) genotypes under light-saturated conditions and at either 2 or 21% O2. Significant variation in gm and A/gsw was found between genotypes at both O2 concentrations, but there was no significant effect of O2 concentration on gm. Further, gm was correlated with photosynthetic rate among the 11 genotypes, but was unrelated to stomatal conductance. The effect of leaf age differed between genotypes, with gm being lower in older leaves for one genotype but not another. This study demonstrates a high level of variation in gm between wheat genotypes; 0.5 to 1.0 μmol m−2 s−1 bar−1. Further, leaf age effects indicate that great care must be taken to choose suitable leaves in studies of genotypic variation in gm and water-use efficiency.

scholarly journals Overlapping Water and Nutrient Use Efficiencies and Carbon Assimilation between Coexisting Simple- and Compound-Leaved Trees from a Valley Savanna

Water ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 3037
Author(s):  
Yang-Si-Ding Wang ◽  
Da Yang ◽  
Huai-Dong Wu ◽  
Yun-Bing Zhang ◽  
Shu-Bin Zhang ◽  
...  
Keyword(s):  
Climate Change ◽  
Water Use Efficiency ◽  
Water Use ◽  
Functional Traits ◽  
Tree Species ◽  
Carbon Assimilation ◽  
Similar Response ◽  
Nutrient Use ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Identifying differences in ecophysiology between simple and compound leaves can help understand the adaptive significance of the compound leaf form and its response to climate change. However, we still know surprisingly little about differences in water and nutrient use, and photosynthetic capacity between co-occurring compound-leaved and simple-leaved tree species, especially in savanna ecosystems with dry-hot climate conditions. From July to September in 2015, we investigated 16 functional traits associated with water use, nutrients, and photosynthesis of six deciduous tree species (three simple-leaved and three compound-leaved species) coexisting in a valley-savanna in Southwest China. Our major objective was to test the variation in these functional traits between these two leaf forms. Overall, overlapping leaf mass per area (LMA), photosynthesis, as well as leaf nitrogen and phosphorus concentrations were found between these coexisting valley-savanna simple- and compound-leaved tree species. We didn’t find significant differences in water and photosynthetic nitrogen or phosphorus use efficiency between simple and compound leaves. Across these simple- and compound-leaved tree species, photosynthetic phosphorus use efficiencies were positively related to LMA and negatively correlated with phosphorus concentration per mass or area. Water use efficiency (intrinsic water use efficiency or stable carbon isotopic composition) was independent of all leaf traits. Similar ecophysiology strategies among these coexisting valley-savanna simple- and compound-leaved species suggested a convergence in ecological adaptation to the hot and dry environment. The overlap in traits related to water use, carbon assimilation, and stress tolerance (e.g., LMA) also suggests a similar response of these two leaf forms to a hotter and drier future due to the climate change.

scholarly journals Intrinsic water use efficiency depends on stomatal aperture rather than stomatal density in C3 and C4 grasses grown at glacial CO2 and low light

2021 ◽  
Author(s):  
Walter K Israel ◽  
Alex Watson-Lazowski ◽  
Zhong-Hua Chen ◽  
Oula Ghannoum
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Stomatal Aperture ◽  
C4 Grasses ◽  
Low Light ◽  
Influx Rate ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

We investigated how stomatal morphology and physiology control intrinsic leaf water use efficiency (iWUE) in grasses. Two C3 and six C4 grasses were grown at ambient (400 μl L-1) or glacial CO2 (180 μl L-1) and high (1000 μmol m-2 s-1) or low light intensity (200 μmol m-2 s-1). C4 grasses tended to have higher iWUE and CO2 assimilation rates, and lower stomatal conductance (gs), operational stomatal aperture (aop) and guard cell K+ influx rate relative to C3 grasses, while stomatal size (SS) and stomatal density (SD) did not vary according to the photosynthetic type. Overall, iWUE and gs depended most on aop and density of open stomata. In turn, aop correlated with K+ influx, stomatal opening speed on transition to high light and SS. Species with higher SD had smaller and faster-opening stomata. Although C4 grasses operated with lower gs and aop at ambient CO2, they showed a greater potential to open stomata relative to maximal stomatal conductance (gmax), indicating heightened stomatal sensitivity and control. We uncover novel links between aop, gs, iWUE and K+ influx amongst grasses and differential K+ influx responses of C4 guard cells to low light, revealing molecular targets for breeding crops with high iWUE.

scholarly journals Coordination of stomata and vein patterns with leaf width underpins water use efficiency in a C4 crop

2021 ◽  
Author(s):  
Ling Pan ◽  
Barbara George-Jaeggli ◽  
Andrew Borrell ◽  
David Jordan ◽  
Fiona Koller ◽  
...  
Keyword(s):  
Energy Balance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Crop Productivity ◽  
Stomatal Aperture ◽  
Leaf Width ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Despite its importance for crop productivity in drought-affected environments, the underlying mechanisms of variation in intrinsic water use efficiency (iWUE) are not well understood, especially in C4 plants. Recently, Cano et al. (2019) discovered that leaf width (LW) correlated negatively with iWUE and positively with stomatal conductance for water vapour (gsw) across several C4 grasses. Here, we analysed these relationships within 48 field-grown genotypes that cover a broad range of variation in LW in Sorghum bicolor, a well-adapted C4 crop to xeric and hot conditions, by measuring and modelling leaf gas exchange and leaf energy balance three times a day, using anatomical traits as potential drivers for iWUE. LW correlated negatively with iWUE and stomatal density, but positively with gsw, interveinal distance of longitudinal veins (IVDL) and the percentage of stomatal aperture relative to maximum. Energy balance modelling showed that wider leaves opened the stomata more to generate a more negative leaf-to-air temperature difference especially at midday, when air temperatures exceeded 40ºC. These results highlight the important role that LW plays in shaping iWUE through modification of vein and stomatal traits and by regulating stomatal aperture. Therefore, LW could be used as a predictor for higher iWUE among sorghum genotypes.

scholarly journals Simultaneous stimulation of RuBP regeneration and electron transport increases productivity and water use efficiency under field conditions

2020 ◽  
Author(s):  
Patricia E. López-Calcagno ◽  
Kenny L. Brown ◽  
Andrew J. Simkin ◽  
Stuart J. Fisk ◽  
Tracy Lawson ◽  
...  
Keyword(s):  
Electron Transport ◽  
Water Use Efficiency ◽  
Water Use ◽  
Plant Biomass ◽  
Carbon Assimilation ◽  
Field Conditions ◽  
Simultaneous Stimulation ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Stimulation Of

AbstractPrevious studies have demonstrated that independent stimulation of either electron transport or RuBP regeneration can increase the rate of photosynthetic carbon assimilation and plant biomass. In this paper, we present evidence that a multi-gene approach to simultaneously manipulate these two processes provides a further stimulation of photosynthesis. We report on the introduction of the cyanobacterial bifunctional enzyme fructose-1,6-bisphosphatase/sedoheptulose-1,7-bisphosphatase or overexpression of the plant enzyme sedoheptulose-1,7-bisphosphatase, together with expression of the red algal protein cytochrome c6, and show that a further increase in biomass accumulation under both glasshouse and field conditions can be achieved. Furthermore, we provide evidence that the simultaneous stimulation of electron transport and RuBP regeneration can lead to enhanced intrinsic water use efficiency under field conditions.One sentence summarySimultaneous stimulation of RuBP regeneration and electron transport results in improvements in biomass yield in glasshouse and field grown tobacco.

The effects of sodium sulphate and sodium chloride on growth, morphology, photosynthesis, and water use efficiency of Chenopodium rubrum

1990 ◽  
Vol 68 (5) ◽  
pp. 999-1006 ◽  
Author(s):  
Patricia Warne ◽  
R. D. Guy ◽  
Lorna Rollins ◽  
D. M. Reid
Keyword(s):  
Sodium Chloride ◽  
Water Use Efficiency ◽  
Water Use ◽  
Stomatal Density ◽  
Stable Carbon Isotope ◽  
Dry Weight ◽  
Sodium Sulphate ◽  
Chenopodium Rubrum ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

The effects of sodium sulphate and sodium chloride salinity on the anatomy, water relations, and photosynthesis of Chenopodium rubrum L. were compared. Low concentrations of either salt stimulated growth, but higher concentrations resulted in large decreases in dry weight and leaf area. Leaf succulence and the number of layers of palisade cells were increased, but these effects were more pronounced with NaCl than with Na2SO4. Stomatal density was reduced at low to moderate salinities, but then increased again at high salinity. Stomatal size was reduced at all salinities. Increasing salinity had no great effect on photosynthetic rates except with older plants grown at the highest level of Na2SO4. Stomatal conductance decreased at all salinities. This reduced transpiration and led to increased intrinsic water use efficiency. Total tissue stable carbon isotope ratios also indicated that water use efficiency was improved. Chenopodium rubrum adjusted osmotically by accumulating electrolytes from the nutrient solution and by synthesizing glycinebetaine. Plants in NaCl limited osmotic adjustment more than those growing in Na2SO4. Despite this, Na2SO4 was more damaging than NaCl and caused earlier leaf senescence at high concentrations.

scholarly journals Directional change in leaf dry matter δ 13C during leaf development is widespread in C3 plants

2020 ◽  
Vol 126 (6) ◽  
pp. 981-990
Author(s):  
Nara O Vogado ◽  
Klaus Winter ◽  
Nerea Ubierna ◽  
Graham D Farquhar ◽  
Lucas A Cernusak
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Developmental Change ◽  
Leaf Expansion ◽  
C3 Plants ◽  
Evergreen Species ◽  
Mature Leaves ◽  
Intrinsic Water Use Efficiency ◽  
Young Leaves ◽  
Use Efficiency

Abstract Background and aims The stable carbon isotope ratio of leaf dry matter (δ 13Cp) is generally a reliable recorder of intrinsic water-use efficiency in C3 plants. Here, we investigated a previously reported pattern of developmental change in leaf δ 13Cp during leaf expansion, whereby emerging leaves are initially 13C-enriched compared to mature leaves on the same plant, with their δ 13Cp decreasing during leaf expansion until they eventually take on the δ 13Cp of other mature leaves. Methods We compiled data to test whether the difference between mature and young leaf δ 13Cp differs between temperate and tropical species, or between deciduous and evergreen species. We also tested whether the developmental change in δ 13Cp is indicative of a concomitant change in intrinsic water-use efficiency. To gain further insight, we made online measurements of 13C discrimination (∆ 13C) in young and mature leaves. Key Results We found that the δ 13Cp difference between mature and young leaves was significantly larger for deciduous than for evergreen species (−2.1 ‰ vs. −1.4 ‰, respectively). Counter to expectation based on the change in δ 13Cp, intrinsic water-use efficiency did not decrease between young and mature leaves; rather, it did the opposite. The ratio of intercellular to ambient CO2 concentrations (ci/ca) was significantly higher in young than in mature leaves (0.86 vs. 0.72, respectively), corresponding to lower intrinsic water-use efficiency. Accordingly, instantaneous ∆ 13C was also higher in young than in mature leaves. Elevated ci/ca and ∆ 13C in young leaves resulted from a combination of low photosynthetic capacity and high day respiration rates. Conclusion The decline in leaf δ 13Cp during leaf expansion appears to reflect the addition of the expanding leaf’s own 13C-depleted photosynthetic carbon to that imported from outside the leaf as the leaf develops. This mixing of carbon sources results in an unusual case of isotopic deception: less negative δ 13Cp in young leaves belies their low intrinsic water-use efficiency.

scholarly journals North America’s oldest boreal trees are more efficient water users due to increased [CO2], but do not grow faster

2019 ◽  
Vol 116 (7) ◽  
pp. 2749-2754 ◽  
Author(s):  
Claudie Giguère-Croteau ◽  
Étienne Boucher ◽  
Yves Bergeron ◽  
Martin P. Girardin ◽  
Igor Drobyshev ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Carbon Allocation ◽  
Stomatal Density ◽  
Anthropogenic Emissions ◽  
Atmospheric Conditions ◽  
Dual Isotope ◽  
Water Users ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency

Due to anthropogenic emissions and changes in land use, trees are now exposed to atmospheric levels of [CO2] that are unprecedented for 650,000 y [Lüthi et al. (2008) Nature 453:379–382] (thousands of tree generations). Trees are expected to acclimate by modulating leaf–gas exchanges and alter water use efficiency which may result in forest productivity changes. Here, we present evidence of one of the strongest, nonlinear, and unequivocal postindustrial increases in intrinsic water use efficiency (iWUE) ever documented (+59%). A dual-isotope tree-ring analysis (δ13C and δ18O) covering 715 y of growth of North America’s oldest boreal trees (Thuja occidentalis L.) revealed an unprecedented increase in iWUE that was directly linked to elevated assimilation rates of CO2 (A). However, limited nutrient availability, changes in carbon allocation strategies, and changes in stomatal density may have offset stem growth benefits awarded by the increased iWUE. Our results demonstrate that even in scenarios where a positive CO2 fertilization effect is observed, other mechanisms may prevent trees from assimilating and storing supplementary anthropogenic emissions as above-ground biomass. In such cases, the sink capacity of forests in response to changing atmospheric conditions might be overestimated.

scholarly journals The use of physiological, biochemical and morpho-anatomical traits in tree breeding for improved water-use efficiency of Quercus robur L.

2019 ◽  
Vol 28 (3) ◽  
pp. e017
Author(s):  
Srđan Stojnić ◽  
Branislav Kovačević ◽  
Marko Kebert ◽  
Erna Vaštag ◽  
Mirjana Bojović ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Stepwise Regression ◽  
Stomatal Density ◽  
Common Garden ◽  
Path Coefficient ◽  
Common Garden Experiment ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
One Year

Aim of study: In the present paper we studied the nature and level of co-dependence between leaf functional traits and intrinsic water-use efficiency (WUEi)in one-year-old Quercus roburL. seedlings, grown in a common garden experiment under moderate drought conditions. The study aimed to identify those traits that might be potentially utilized to improve leaf-level WUEi, and therefore be used in breeding programmes to enhance drought adaptation of Q. roburtree species.Area of study: The study was carried out at the common garden experiment established within UNESCO Biosphere Reserve Mura-Drava-Danube.Material and methods: The study involved one-year-old seedlings of eight half-sib lines of Q. robur. We analyzed 18 leaf parameters; i.e. physiological, biochemical, morphological and anatomical. Data were processed using multivariate statistical methods: a) principal component analysis, b) stepwise regression analysis, and c) path coefficient analysis.Main results: The results evidenced that leaf stomatal traits, particularly stomatal density (SD),and leaf dry mass per unit leaf area (LMA) were the most important traits associated closely with WUEi.Stomatal density achieved the highest score on PC1 (0.825), in which WUEihad the highest loading (0.920), as well. SDwas also included first in stepwise regression model. Research highlights: The results demonstrated that under moderate water stressWUEiin Q. robur half-sib lines were mainly the result of the plants’ structural acclimation to surrounding environmental conditions.

Sign in / Sign up

Export Citation Format

Share Document