Variation in mesophyll conductance among Australian wheat genotypes

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.

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

Functional Plant Biology ◽

10.1071/fp07166 ◽

2007 ◽

Vol 34 (10) ◽

pp. 918 ◽

Cited By ~ 12

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.

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Genetic Variability of Drought Adaptive Traits in Nepalese Wheat (Triticum aestivum L.) Germplasm

Hydro Nepal Journal of Water Energy and Environment ◽

10.3126/hn.v11i1.7208 ◽

2012 ◽

pp. 64-68

Author(s):

Dipendra Pokharel ◽

Madhav Pandey

Keyword(s):

Triticum Aestivum ◽

Genetic Variability ◽

Water Use Efficiency ◽

Water Content ◽

Water Use ◽

Triticum Aestivum L ◽

Leaf Water Content ◽

Adaptive Traits ◽

Wheat Genotypes ◽

Use Efficiency

Wheat (Triticum aestivum L.) is one of the major cereal crops vital for global food supply. Most of the wheat crop in developing world including that of Nepal is either grown with limited irrigation or under rainfed conditions and thus face moisture stress at one or more growth stages limiting grain yield. An experiment was carried out at the Institute of Agriculture and Animal Science, Rampur, Nepal, to evaluate the genetic variability of selected drought adaptive traits in Nepalese wheat germplasm. The wheat genotypes evaluated comprised of Nepalese landraces and commercial cultivars, CIMMYT (International Center for Maize and Wheat Improvement) derived advanced introduction lines and three checks with differential drought adaptability. The wheat genotypes were grown in pots (single plant) arranged in a replicated split plot design in greenhouse under two contrasting moisture regimes, optimum and moisture stressed. The genotypes were evaluated for water use, water use efficiency, relative leaf water content and biomass production. The ANOVA (Analysis of Variance) revealed significant variation between environments and among the wheat genotypes for most of the traits studied. A wide range of variability was observed for water use, water use efficiency, biomass yield and relative leaf water content in moisture stressed and non–stressed environments. Nepalese cultivar Gautam showed a number of favorable drought adaptive traits, whereas, Bhrikuti was average in this respect. Based on the scores of drought adaptive traits recently released Cultivar (cv). Vijay was characterized as drought sensitive. A number of landraces and advanced breeding lines showed high level of water use efficiency and other positive traits for drought adaptation. DOI: http://dx.doi.org/10.3126/hn.v11i1.7208 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.64-68

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Mesophyll conductance to CO2 and Rubisco as targets for improving intrinsic water use efficiency in C3 plants

Plant Cell & Environment ◽

10.1111/pce.12622 ◽

2015 ◽

Vol 39 (5) ◽

pp. 965-982 ◽

Cited By ~ 94

Author(s):

J. Flexas ◽

A. Díaz-Espejo ◽

M. A. Conesa ◽

R. E. Coopman ◽

C. Douthe ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

C3 Plants ◽

Mesophyll Conductance ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency

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Accounting for mesophyll conductance substantially improves 13 C‐based estimates of intrinsic water‐use efficiency

New Phytologist ◽

10.1111/nph.16958 ◽

2020 ◽

Vol 229 (3) ◽

pp. 1326-1338

Author(s):

Wei Ting Ma ◽

Guillaume Tcherkez ◽

Xu Ming Wang ◽

Rudi Schäufele ◽

Hans Schnyder ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Mesophyll Conductance ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency

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GAS EXCHANGE AND PHOTOCHEMICAL EFFICIENCY IN LIMA BEAN GENOTYPES GROWN IN COMPACTED SOILS

Revista Caatinga ◽

10.1590/1983-21252018v31n206rc ◽

2018 ◽

Vol 31 (2) ◽

pp. 306-314

Author(s):

RENATO FRANCISCO DA SILVA SOUZA ◽

DJAIL SANTOS ◽

WALTER ESFRAIN PEREIRA ◽

FABRÍCIO LOPES DE MACEDO ◽

JHONY VENDRUSCOLO

Keyword(s):

Gas Exchange ◽

Water Use Efficiency ◽

Water Use ◽

Photosynthetic Rate ◽

Soil Compaction ◽

Photochemical Efficiency ◽

Lima Bean ◽

Phaseolus Lunatus ◽

Intrinsic Water Use Efficiency ◽

Use Efficiency

ABSTRACT The effects of soil compaction on crop growth and productivity have been well studied in recent years, however, studies on the physiological responses of crops to compaction are scarce. The objective of this study was to evaluate the effect of soil compaction on gas exchange, and photochemical efficiency of lima bean (Phaseolus lunatus L.) genotypes of different growth habits. The experimental design was a randomized block in a 3×4 factorial arrangement, with three lima bean genotypes (Branca-Pequena, Orelha-de-Vó and Roxinha) and four compaction levels (soil densities of 1.1, 1.3, 1.5 and 1.7 g cm-3), with four replications. The following variables were evaluated at 38 days after sowing: photosynthetic rate (A), leaf transpiration (E), stomatal conductance (gs), internal CO2 concentration (Ci), instantaneous water use efficiency (WUE), intrinsic water use efficiency (iWUE), instantaneous carboxylation efficiency (iCE) and photochemical efficiency (Fo, Fm, Fv and Fv/Fm). The data were subjected to analysis of variance at 5% probability by the F test. The genotypes showed a reduction in the photosynthetic rate with increasing soil compaction. The soil compaction affected the photochemical efficiency of the genotype Orelha-de-Vó, with the Fm and Fv fitting to the linear model, and the Fv/Fm fitting to the quadratic model. The genotype Orelha-de-Vó had the highest rate of E and gs at the soil densities of 1.24 and 1.29 g cm-3, respectively. Regarding the photosynthetic rate, the genotype Roxinha is more efficient than Branca-Pequena at the soil density of 1.7 g cm -3.

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