Stomatal conductance and CO2 assimilation as screening tools for drought resistance in sorghum

1991 ◽  
Vol 71 (3) ◽  
pp. 689-694 ◽  
Author(s):  
Safaa H. Al-Hamdani ◽  
Jennifer M. Murphy ◽  
Glenn W. Todd
Keyword(s):  
Survival Rate ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Soil Water ◽  
Water Use ◽  
Drought Resistance ◽  
Water Availability ◽  
Soil Water Availability ◽  
Use Efficiency ◽  
Sorghum Bicolor L

Stomatal conductance and CO2 assimilation were evaluated at three different levels of soil water availability as tools for estimating relative drought resistance in sorghum (Sorghum bicolor (L.) Moench) at vegetative stage (preanthesis). Four genotypes differing in drought resistance in the field (A Texas line TX 622; Oklahoma lines, BOK 11 and BOK 111; and IN-15, a line from the Sudan of Africa) were investigated. Plants were grown in a growth chamber at 27 °C, (day/night) day length of 14 h and photosynthetic photon flux density of 350 μmol m−2 S−1. Three weeks after germination, plants were divided into control, 50% and 25% soil water saturation groups. At the end of the second week of treatment, simultaneous measurements were made of stomatal conductance, CO2 assimilation, leaf water potential and transpiration, on the youngest most mature leaf. After gas exchange measurements were taken, leaf water potential was measured. In a separate experiment, survival rate under water stress conditions was also determined on plants grown under the same conditions as above. Four weeks after germination, the plants were subjected to two cycles of drought and the survival rate and growth of each genotype determined. Survival rate and growth throughout dought cycles I and II was, in the decreasing order of, IN-15, BOK 111, TX 622 and BOK 11. Water potential, stomatal conductance and CO2 assimilation of each genotype declined with decreased soil water availability; the smallest decrease was observed in IN-15 and the largest decreases in BOK 111, followed by TX 622 and BOK 11. Water use efficiency of each genotype was increased, in the same order as above, with decreased soil water availability. This correlates with the ranking obtained in the artificial drought test. In conclusion, stomatal conductance and CO2 assimilation appear to be useful tools for screening sorghum genotypes at vegetative stage (preanthesis) of growth for drought resistance. Key words: Water potential, water use efficiency (WUE), Sorghum bicolor (L.) Moench

scholarly journals Carbon–water flux coupling under progressive drought

2019 ◽  
Vol 16 (13) ◽  
pp. 2557-2572 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Adriaan J. Teuling ◽  
Markus Reichstein
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Carbon Assimilation ◽  
Soil Water Availability ◽  
Natural Experiments ◽  
Water Limitation ◽  
Dry Down ◽  
Use Efficiency

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.

scholarly journals Carbon–Water Flux Coupling Under Progressive Drought

2018 ◽  
Author(s):  
Sven Boese ◽  
Martin Jung ◽  
Nuno Carvalhais ◽  
Adriaan J. Teuling ◽  
Markus Reichstein
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Water Flux ◽  
Carbon Assimilation ◽  
Soil Water Availability ◽  
Natural Experiments ◽  
Dry Down ◽  
Use Efficiency

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.

Maize water use efficiency and evapotranspiration response to N supply under contrasting soil water availability

2015 ◽  
Vol 178 ◽  
pp. 8-15 ◽  
Author(s):  
M. Hernández ◽  
L. Echarte ◽  
A. Della Maggiora ◽  
M. Cambareri ◽  
P. Barbieri ◽  
...  
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Soil Water Availability ◽  
N Supply ◽  
Use Efficiency

scholarly journals Clonal Behavior in Response to Soil Water Availability in Tempranillo Grapevine cv: From Plant Growth to Water Use Efficiency

Agronomy ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 862
Author(s):  
Ignacio Tortosa ◽  
Jose M. Escalona ◽  
Guillermo Toro ◽  
Cyril Douthe ◽  
Hipolito Medrano
Keyword(s):  
Plant Growth ◽  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Growth Parameters ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Soil Water Availability ◽  
Use Efficiency

Climate change threatens worldwide grapevine production, especially in Mediterranean areas. To assume this challenge, the replacement of plant material to choose one more adapted to the new environmental conditions has been proposed as one of the possible solutions. Thus, the study of genetic variability in water-use efficiency (WUE) is needed to guarantee the survival of viticulture in those critical areas. In this study, the variability of WUE in 23 Tempranillo clones growth in pots and submitted to well-watered conditions and moderate water stress was studied along two consecutive years. Leaf net photosynthesis (AN), stomatal conductance (gs), and plant growth parameters were measured, in addition the instrisic WUE (AN/gs), biomass production, and water consumed were calculated. Results show a clear genotype effect for most of the studied parameters, but, with an important year by year variability. We identified different clonal behavior in response to soil water availability, that permits to classify them as water-savers vs water-spenders. In general, there was no found relationship between leaf and plant WUE, even some genotypes as 232 or 1048 were coincident in higher leaf WUE showed highly productive in terms of biomass accumulation per unit of water applied.

scholarly journals Soil water availability for drip-irrigated common bean crop

2020 ◽  
Vol 50 ◽  
Author(s):  
Edson Fagne dos Santos ◽  
Silvanio Rodrigues dos Santos ◽  
Abner José de Carvalho ◽  
Ignácio Aspiazu ◽  
Polyanna Mara de Oliveira
Keyword(s):  
Water Use Efficiency ◽  
Common Bean ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Block Design ◽  
Soil Water Availability ◽  
Maximum Water ◽  
Use Efficiency ◽  
Agronomic Yield

ABSTRACT Minimum limits of soil water storage should be established for the irrigation management of crops, in order to satisfactorily provide water to plants. This study aimed to define the soil water availability factor (f factor) that provides the maximum agronomic yield and maximum water-use efficiency for drip-irrigated common bean cultivars. The experiment was carried out in a randomized block design, with four replications. The treatments were arranged in split plots, with the plots consisting of f factors (0.20, 0.35, 0.50, 0.65 and 0.80) and subplots consisting of common bean cultivars (BRS Pérola and BRS Estilo). The use of f factors between 0.30 and 0.35 is recommended for common bean crops to obtain the maximum agronomic yield and maximum water-use efficiency. The BRS Estilo cultivar presents a water-use efficiency 16 % higher than the BRS Pérola.

Effects of soil water availability on water use efficiency of Eucalyptus cloeziana and Eucalyptus argophloia plants

2003 ◽  
Vol 51 (2) ◽  
pp. 159 ◽  
Author(s):  
Michael R. Ngugi ◽  
Mark A. Hunt ◽  
David Doley ◽  
Paul Ryan ◽  
Peter J. Dart
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Isotope Composition ◽  
Soil Water Availability ◽  
Δ13c Values ◽  
Use Efficiency ◽  
Collar Diameter ◽  
Eucalyptus Cloeziana

Effects of soil water availability on transpiration efficiency (WUET), instantaneous water use efficiency (WUEi) and carbon isotope composition (δ13C) were investigated in 7-month-old plants of humid coastal (Gympie) and dry inland (Hungry Hills) provenances of Eucalyptus cloeziana F.Muell. and in a dry inland provenance of E.�argophloia Blakely (Chinchilla), supplied with 100 (W100), 70 (W70) and 50% (W50) of their water requirements. At W100, WUET of the three provenances were not significantly different but as available soil moisture decreased, E. argophloia produced greater biomass and demonstrated significantly higher WUET than either E. cloeziana provenance. Midday WUEi was not significantly affected by watering regime within each provenance but was lowest in E. argophloia. A decrease in soil water availability caused a consistent increase in δ13C values in all three provenances; however, δ13C values of E. argophloia in all three water regimes were significantly lower than those of E. cloeziana provenances, which did not differ significantly from each other. For all three provenances, δ13C was not correlated with WUEi but height and root collar diameter were negatively correlated to δ13C. There was little evidence of differences in δ13C, WUET and WUEi between E. cloeziana provenances but clear differences between E. cloeziana and E. argophloia. The high WUET, low WUEi and low δ13C for E. argophloia may have implications in the selection of Eucalyptus provenances for commercial forestry in low-rainfall regions.

scholarly journals Yield and water use of cherry tomato under water availability and potassium doses

2018 ◽  
Vol 22 (5) ◽  
pp. 326-331 ◽  
Author(s):  
Adriano B. Pacheco ◽  
Tonny J. A. da Silva ◽  
Edna M. Bonfim-Silva ◽  
Hamilton A. W. Castro ◽  
Marcio Koetz
Keyword(s):  
Water Use Efficiency ◽  
Soil Water ◽  
Water Use ◽  
Water Availability ◽  
Soil Water Availability ◽  
Cherry Tomato ◽  
Soil Water Tension ◽  
Tomato Yield ◽  
Use Efficiency ◽  
Water Tension

ABSTRACT The objective of this study was to evaluate the yield and water use of cherry tomatoes under soil water availability and potassium (K) doses in a greenhouse. The experiment was conducted in randomized blocks in a 52 fractional factorial design, corresponding to five levels of water availability and five K doses, with 13 combinations (4-0; 4-250; 4-500; 14-125; 14-375; 24-0; 24-250; 24-500; 34-125; 34-375; 44-0; 44-250; 44-500) (kPa-mg dm-3) and four replicates. A drip irrigation system with semi-automated irrigation control was used. The analyzed variables were shoot dry matter, number of fruits, yield, water consumption and water use efficiency. Highest cherry tomato yield occurs at soil water tension of 24 kPa and K dose of 290 mg dm-3. Soil water tension of 44 kPa and K dose of 290 mg dm-3 allow for higher water use efficiency in cherry tomato. Cherry tomato yield and water use are influenced by soil water availability and K doses in greenhouse.

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