scholarly journals Water Use, Leaf Cooling and Carbon Assimilation Efficiency of Heat Resistant Common Beans Evaluated in Western Amazonia

2021 ◽  
Vol 12 ◽  
Author(s):  
Juan Carlos Suárez ◽  
Milan O. Urban ◽  
Amara Tatiana Contreras ◽  
Jhon Eduar Noriega ◽  
Chetan Deva ◽  
...  

In our study, we analyzed 30years of climatological data revealing the bean production risks for Western Amazonia. Climatological profiling showed high daytime and nighttime temperatures combined with high relative humidity and low vapor pressure deficit. Our understanding of the target environment allows us to select trait combinations for reaching higher yields in Amazonian acid soils. Our research was conducted using 64 bean lines with different genetic backgrounds. In high temperatures, we identified three water use efficiency typologies in beans based on detailed data analysis on gasometric exchange. Profligate water spenders and not water conservative accessions showed leaf cooling, and effective photosynthate partitioning to seeds, and these attributes were found to be related to higher photosynthetic efficiency. Thus, water spenders and not savers were recognized as heat resistant in acid soil conditions in Western Amazonia. Genotypes such as BFS 10, SEN 52, SER 323, different SEFs (SEF 73, SEF 10, SEF 40, SEF 70), SCR 56, SMR 173, and SMN 99 presented less negative effects of heat stress on yield. These genotypes could be suitable as parental lines for improving dry seed production. The improved knowledge on water-use efficiency typologies can be used for bean crop improvement efforts as well as further studies aimed at a better understanding of the intrinsic mechanisms of heat resistance in legumes.

2021 ◽  
Author(s):  
Pablo Affortit ◽  
Branly Effa Effa ◽  
Mame Sokhatil Ndoye ◽  
Daniel Moukouanga ◽  
Nathalie Luchaire ◽  
...  

Because water availability is the most important environmental factor limiting crop production, improving water use efficiency, the amount of carbon fixed per water used, is a major target for crop improvement. In rice, the genetic bases of transpiration efficiency, the derivation of water use efficiency at the whole-plant scale, and its putative component trait transpiration restriction under high evaporative demand, remain unknown. These traits were measured in a panel of 147 African rice Oryza glaberrima genotypes, known as potential sources of tolerance genes to biotic and abiotic stresses. Our results reveal that higher transpiration efficiency is associated with transpiration restriction in African rice. Detailed measurements in a subset of highly differentiated genotypes confirmed these associations and suggested that the root to shoot ratio played an important role in transpiration restriction. Genome wide association studies identified marker-trait associations for transpiration response to evaporative demand, transpiration efficiency and its residuals, that links to genes involved in water transport and cell wall patterning. Our data suggest that root shoot partitioning is an important component of transpiration restriction that has a positive effect on transpiration efficiency in African rice. Both traits are heritable and define targets for breeding rice with improved water use strategies.


2019 ◽  
Vol 70 (1) ◽  
pp. 781-808 ◽  
Author(s):  
Andrew D.B. Leakey ◽  
John N. Ferguson ◽  
Charles P. Pignon ◽  
Alex Wu ◽  
Zhenong Jin ◽  
...  

The ratio of plant carbon gain to water use, known as water use efficiency (WUE), has long been recognized as a key constraint on crop production and an important target for crop improvement. WUE is a physiologically and genetically complex trait that can be defined at a range of scales. Many component traits directly influence WUE, including photosynthesis, stomatal and mesophyll conductances, and canopy structure. Interactions of carbon and water relations with diverse aspects of the environment and crop development also modulate WUE. As a consequence, enhancing WUE by breeding or biotechnology has proven challenging but not impossible. This review aims to synthesize new knowledge of WUE arising from advances in phenotyping, modeling, physiology, genetics, and molecular biology in the context of classical theoretical principles. In addition, we discuss how rising atmospheric CO2concentration has created and will continue to create opportunities for enhancing WUE by modifying the trade-off between photosynthesis and transpiration.


2019 ◽  
Vol 16 (13) ◽  
pp. 2557-2572 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Adriaan J. Teuling ◽  
Markus Reichstein

Abstract. Water-use efficiency (WUE), defined as the ratio of carbon assimilation over evapotranspiration (ET), is a key metric to assess ecosystem functioning in response to environmental conditions. It remains unclear which factors control this ratio during periods of extended water limitation. Here, we used dry-down events occurring at eddy-covariance flux tower sites in the FLUXNET database as natural experiments to assess if and how decreasing soil-water availability modifies WUE at ecosystem scale. WUE models were evaluated by their performance to predict ET from both the gross primary productivity (GPP), which characterizes carbon assimilation at ecosystem scale, and environmental variables. We first compared two water-use efficiency models: the first was based on the concept of a constant underlying water-use efficiency, and the second augmented the first with a previously detected direct influence of radiation on transpiration. Both models predicting ET strictly from atmospheric covariates failed to reproduce observed ET dynamics for these periods, as they did not explicitly account for the effect of soil-water limitation. We demonstrate that an ET-attenuating soil-water-availability factor in junction with the additional radiation term was necessary to accurately predict ET flux magnitudes and dry-down lengths of these water-limited periods. In an analysis of the attenuation of ET for the 31 included FLUXNET sites, up to 50 % of the observed decline in ET was due to the soil-water-availability effect we identified in this study. We conclude by noting that the rates of ET decline differ significantly between sites with different vegetation and climate types and discuss the dependency of this rate on the variability of seasonal dryness.


2003 ◽  
Vol 128 (3) ◽  
pp. 356-362 ◽  
Author(s):  
D. Michael Glenn ◽  
Amnon Erez ◽  
Gary J. Puterka ◽  
Patricia Gundrum

Processed-kaolin particle films (PKPFs) are used commercially in large quantities on horticultural crops to repel insects, and reduce heat stress and solar injury of fruit. Our studies determined the effect of two processed-mineral particle film materials (kaolin and calcium carbonate), on whole plant carbon assimilation, water use efficiency, yield, mean fruit weight and quality in `Empire' apple [(Malus ×sylvestris (L.) Mill var. domestica (Borkh Mansf.))] over a four-year period. The application of a PKPF reduced canopy temperature, and probably reduced environmental stress, resulting in increased mean fruit weight and red color in two of the four years of the study. Whole canopy carbon assimilation studies indicated increased carbon assimilation only under conditions of high air temperature. The PKPF sprayed leaves also had reduced water use efficiency; likely due to increased stomatal conductance associated with reduced leaf temperature. Calcium carbonate had none of the positive effects of PKPF and reflected more photosynthetically active radiation (PAR) than the PKPF.


2007 ◽  
Vol 34 (10) ◽  
pp. 918 ◽  
Author(s):  
Gregory J. Jordan ◽  
Timothy J. Brodribb

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.


2018 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Adriaan J. Teuling ◽  
Markus Reichstein

Abstract. Water-use efficiency, defined as the ratio of carbon assimilation over evapotranspiration (ET), is a key metric to assess ecosystem functioning in response to environmental conditions. It remains unclear which factors control this ratio during periods of extended water-limitation, and current semi-empirical water-use efficiency models fail to reproduce observed ET dynamics for these periods. Here, we use dry-down events occurring at eddy-covariance flux tower sites in the FLUXNET database as natural experiments to assess if and how decreasing soil-water availability modifies water-use efficiency on ecosystem scale. We demonstrate that an attenuating soil-water availability factor in junction with a previously discovered additive radiation term is necessary to accurately predict ET flux magnitudes and dry-down lengths of these water-limited periods. In an analysis of the attenuation, 20–33 % of the observed decline in ET was due to the previously unconsidered soil-water availability effect. We conclude by noting the rates of ET decline differ significantly between FLUXNET sites with tall and short vegetation types and discuss the dependency of this rate on the variability of seasonal dryness.


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