Special Issue "Photosynthetic Performance and Water-Use-Efficiency in Grasses"

A special issue of Agronomy (ISSN 2073-4395). This special issue belongs to the section "Water Use and Irrigation".

Deadline for manuscript submissions: 30 September 2020.

Special Issue Editors

Dr. Samuel Taylor
Guest Editor
Lancaster Environment Centre, Lancaster University, Lancaster, United Kingdom
Interests: Physiology and ecophysiology of grasses; photosynthesis; water relations; plant growth analysis; leaf gas exchange
Dr. Meisha Holloway-Phillips
Guest Editor
Department of Environmental Sciences - Botany, University of Basel, Basel, Switzerland
Interests: plant CO2 and H2O exchange; stable isotopes; mesophyll conductance; hydraulic conductance
Dr. Andrew Merchant
Guest Editor
Centre for Carbon Water and Food, The University of Sydney, 380 Werombi road, Camden, 2570 NSW, Australia
Interests: plant physiology; isotopes; food chemistry; plant water relations; mass spectrometry
Dr. Gemma Molero
Guest Editor
International Maize and Wheat Improvement Center (CIMMYT), Texcoco, Mexico
Interests: wheat physiology for yield enhancement; photosynthesis; genetic screening; field phenotyping

Special Issue Information

Dear Colleagues,

Grasses produce key staple grains, sugars, fodder, feedstocks, and materials that support manufacturing and construction, as well as being critical to land reclamation. Historical ecological impacts of agriculture have been tied to the introduction and improvement of agronomically important grasses, and the future development of grass crops will influence agricultural responses to climate change and the challenge of improving the sustainability of resources.

Grasses demonstrate both evolutionary and ecological flexibility, having repeatedly evolved novel photosynthetic systems and unique morphological and life-history strategies, allowing them to occupy almost every habitat on Earth. The success of grasses in agricultural production has been the result of intensive yield selection and improved agronomic practices, yet many aspects of physiology and phenology unique to grasses remain understudied.

Critical insights are sought into how photosynthetic performance and the efficiency of water use have impacted and may impact grass agronomic management. Reviews, experimental and/or modelling studies will quantitatively assess the impacts of physiology, allocation, and/or phenology, at tissue, organ, plant, canopy, and/or crop levels. Contexts include domestication and selection histories, genetic variation, novel strategies for crop improvement, interspecific comparisons, and cropping systems incorporating grasses.

Dr. Samuel Taylor
Dr. Meisha Holloway-Phillips
Dr. Andrew Merchant
Dr. Gemma Molero
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Agronomy is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.


  • grasses
  • photosynthesis
  • water use
  • agronomy
  • crop improvement
  • forage
  • fodder
  • grain
  • feedstock

Published Papers (2 papers)

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Jump to: Review

Open AccessArticle
Maintenance of Photosynthesis as Leaves Age Improves Whole Plant Water Use Efficiency in an Australian Wheat Cultivar
Agronomy 2020, 10(8), 1102; https://doi.org/10.3390/agronomy10081102 - 30 Jul 2020
Leaf-level water use efficiency (WUEi) is often used to predict whole plant water use efficiency (WUEwp), however these measures rarely correlate. A better understanding of the underlying physiological relationship between WUEi and WUEwp would enable [...] Read more.
Leaf-level water use efficiency (WUEi) is often used to predict whole plant water use efficiency (WUEwp), however these measures rarely correlate. A better understanding of the underlying physiological relationship between WUEi and WUEwp would enable efficient phenotyping of this important plant trait to inform future crop breeding efforts. Although WUEi varies across leaf age and position, less is understood about the regulatory mechanisms. WUEi and WUEwp were determined in Australian (cv. Krichauff) and UK (cv. Gatsby) wheat cultivars. Leaf gas exchange was measured as leaves aged and evaluated in relation to foliar abscisic acid (ABA) and 1-aminocyclopropane-1-carboxylic acid (ACC) concentration, chlorophyll content and Rubisco activity. Carbon dioxide (CO2) assimilation (A) declined more rapidly as leaves aged in the lower WUEwp genotype Gatsby. Both ACC concentration and Rubisco activity declined as leaves aged, but neither explained the variation in A. Further, stomatal conductance (gs) and stomatal sensitivity to ABA were unchanged as leaves aged, therefore WUEi was lowest in Gatsby. Maintenance of A as the leaves aged in the Australian cultivar Krichauff enabled greater biomass production even as water loss continued similarly in both genotypes, resulting in higher WUEwp. Full article
(This article belongs to the Special Issue Photosynthetic Performance and Water-Use-Efficiency in Grasses)
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Jump to: Research

Open AccessReview
A Review of Modeled Water Use Efficiency of Highly Productive Perennial Grasses Useful for Bioenergy
Agronomy 2020, 10(3), 328; https://doi.org/10.3390/agronomy10030328 - 01 Mar 2020
Whole plant productivity is obviously the ultimate product of leaf photosynthesis and this has led to numerous efforts to relate the two. However, often with perennial grasses, plant productivity is more sink-limited than source-limited, causing the linkage between the photosynthetic rate and productivity [...] Read more.
Whole plant productivity is obviously the ultimate product of leaf photosynthesis and this has led to numerous efforts to relate the two. However, often with perennial grasses, plant productivity is more sink-limited than source-limited, causing the linkage between the photosynthetic rate and productivity to be weak or nonexistent. This has led to a different approach, characterizing plant productivity in terms of the efficiency of intercepted light use in producing biomass, also called radiation use efficiency. Likewise, the efficiency of the use of water to produce plant biomass, or water use efficiency, has been the object of much interest. The use of a simulation model to quantify biomass, using radiation use efficiency in parallel with a daily water balance simulation, allows for the effective calculation of water use efficiency. In this project, the process of determining radiation use efficiency with field data is described, as well as example values for highly productive perennial grasses useful for feedstock for bioenergy. In addition, values of water use efficiency for these grasses are reported and compared with other perennial grasses and common cultivated crops. Full article
(This article belongs to the Special Issue Photosynthetic Performance and Water-Use-Efficiency in Grasses)
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Planned Papers

The below list represents only planned manuscripts. Some of these manuscripts have not been received by the Editorial Office yet. Papers submitted to MDPI journals are subject to peer-review.

Carbon isotope composition as phenotyping approach for drought adaptation in durum wheat

Rut Sanchez-Bragado1, Maria Newcomb2, Fadia Chairi3, Giuseppe E. Condorelli4, Rick Ward2, Roberto Tuberosa4, Jose L. Araus3, Maria D. Serret3*

1Department of Crop and Forest Sciences, Universtity of Lleida, Lleida, Spain and AGROTECNIO (Center of Research in Agrotechnology), Lleida, Spain

2Maricopa Agricultural Center, University of Arizona, Tucson, AZ, United States

3Section of Plant Physiology, University of Barcelona, Barcelona and AGROTECNIO (Center of Research in Agrotechnology), Lleida, Spain

4Department of Agricultural Sciences, University of Bologna, Bologna, Italy

3US Arid Land Agricultural Research Center, USDA-ARS, Maricopa, AZ, United States

*To whom the correspondence should be addressed.

Abstract: Carbon isotope composition (δ13C) in plant matter is not just a well-accepted proxy for water use efficiency in C3 plants but in many cases it may also inform in a broad sense on the water status of the crop, with higher δ13C values reflecting more water stress conditions. A panel of 248 elite durum wheat (Triticum turgidum L. ssp. durum Desf.) accessions were grown at the Maricopa Phenotyping platform (AZ, US) under well-watered conditions until early post anthesis and then irrigation was stopped and plots were harvested (for final biomass) about three weeks after. For each plot shoots were sampled at these two moments and then δ13C was analyzed. Globally δ13C values increased from the first to the second sampling date, in agreement with the occurrence of a progressive water stress. Nevertheless, genotypic differences existed in the extend of changes in δ13C, with some accessions showing not changes, which suggest they have suffered less water stress. In addition, δ13C was negatively related with total final biomass, suggesting accessions exhibiting lower water use efficiency were keeping better water status and then performing better.


Estimating source capacity and photosynthesis up-regulation in lines with contrasting grain partitioning and source-sink balance

Carolina Rivera-Amado1, Gemma Molero1, Eliseo Trujillo-Negrellos2, Matthew Reynolds1 and John Foulkes2

1CIMMYT, Mexico; 2University of Nottingham, UK.

Abstract: The optimization of dry matter (DM) partitioning among plant organs towards increases in grain number and harvest index should consider effects on post-anthesis photosynthetic capacity. Moreover, potential differences in source-sink balance - response to changes in sink demand - should also be taken into consideration.  In this study, we estimated source-sink balance and organ post-anthesis contribution to grain growth by comparing grain weight (GW) responses to manipulation treatments in a set of 26 spring elite wheat cultivars across different years. The treatments were applied 10 days after anthesis and consisted on i) de-graining (removing half of the spikelets, DEG), ii) spike covering (SPKCOV), iii) top three leaves defoliation (DEF), iv) leaf-sheath covering (LSCOV), v) defoliation+leaf-sheath covering (DEF+LSCOV) and vi) defoliation by area (DEFarea). Additionally, the contribution of pre-anthesis assimilates (CPA) were estimated and photosynthesis measurements were carried out. Results showed a wide and significant variation (P <0.001) in responses to de-graining from 1% to 27.9%. Spike photosynthesis contribution varied from 30 to 52% (P <0.001). Overall decreases in GW in response to DEF ranged from 6.5 to 16% (P <0.05) across two years. Surprisingly, decreases in final GW in response to LSCOV (laminae untouched) were as high as 11.2% (P <0.01) in the same experiments.  There was a tendency for spike photosynthesis up-regulation as a response to defoliation and leaf-sheath covering treatments among a subset of four cultivars evaluated. Our results indicate that the grain yield of the 26 elite spring wheat cultivars is co-limited by source and sink, therefore, breeding efforts should focus in parallel on both source and sink related traits. Leaf lamina contribution to final GW during grain filling was lower than expected and on the contrary leaf-sheath contribution to grain filling proved to be an important trait to exploit under environments limited by source and also crucial to consider in the optimization of DM partitioning among plant organs.


Photosynthetic capacity and efficiency as a selection criterion in wheat breeding

Gemma Molero1 and Matthew Reynolds1

1International Maize and Wheat Improvement Center (CIMMYT), El Batán, Texcoco, CP 56130, Mexico.

Abstract: The potential of genetic diversity in leaf photosynthesis has received attention in the last years but it is still largely ignored in crop improvement. Total crop photosynthesis is dependent on the ability of the canopy to intercept and capture light and the photosynthetic capacity and efficiency of the canopy. Different traits were evaluated on a set of 60 elite genotypes on raised beds and basin, under potential conditions. Data of biomass and cumulative radiation interception were pooled to observe Radiation Use Efficiency (RUE) dynamics along the crop cycle and to compare the two planting systems. Results showed better RUE in basin than raised beds explaining higher biomass and yield in basin compared to beds. RUE is determined by canopy architecture during crop development. In order to identify optimal canopy architecture for increased crop photosynthesis, four different genotypes with contrasting leaf angle and canopy aperture were selected and different traits were evaluated. More erect leaf angles and open canopies presented greater light penetration deeper into the canopy and showed a higher photosynthetic rate. This higher photosynthetic rate was translated into higher yield and biomass compared with other canopy architectures. In addition, chlorophyll distribution along the canopy demonstrated associations with RUE. At the canopy level, modification of leaf architecture may improve RUE by permitting a light distribution profile that reduces the number of leaves experiencing wasteful and potentially destructive supersaturated light levels, while increasing light penetration to canopy levels where photosynthesis responds linearly to light.


Warming diminishes net carbon gain and leads to significant reduction in the productivity in two key pasture species

 Vinod Jacob, Haiyang Zhang, Amy Churchill, Belinda Medlyn, Sally Power, Brendan Choat, Jinyan Yang and David Tissue

Abstract: High temperature stress imposes major limitations on the productivity of agricultural systems such as pastures, and climate change mediated increases in global temperatures are set to exacerbate these limitations. A large proportion of Australian pastures are currently growing in areas that frequently experience temperatures near or above their thermal optimums for growth. Hence, a further increase in temperature may greatly reduce production of many pasture species in the future.

Here we sought to understand how warmer growth temperature influences gas exchange and net primary productivity in key pasture species; to do this, we measured photosynthetic capacity, dark respiration and WUE of plants exposed to different temperature regimes, reflecting the current maximum average temperature and the predicted average temperature for the region within this century. We grew two widely cultivated C3 pasture species, Medicago sativa (legume) and Festuca arundinacea (grass), in a climate-controlled facility exposed to two temperature treatments (ambient: 26C, aT; elevated: 30C, eT). We maintained soil water at non-limiting conditions in both temperature treatments to mitigate potential temperature-driven changes in evapotranspiration. Gas exchange parameters were measured throughout the experiment and concluded after 4 months of growth when all plants were destructively harvested.

M. sativa grown under warming exhibited reduced photosynthetic capacity, increased leaf dark respiration and decreased intrinsic (Asat/gs) and whole plant WUE (δ13C). F. arundinacea grown under warming showed little change in photosynthetic capacity, but had higher respiration and lower WUE. Growth temperature had no impact on the thermal optimum of photosynthesis (Topt) in F. arundinacea, while Topt increased in M. sativa. Warming generated significant reductions in above- and below-ground biomass despite some physiological adjustment, indicating the potential for significant declines in pasture productivity in a warmer future world.

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