scholarly journals Determining Factors of Ranges of Water-use Efficiency, Net Assimilation Rate and Transpiration Rate. An Analysis Using .ALPHA.-.BETA. Method.

1997 ◽  
Vol 10 (1) ◽  
pp. 32-43
Author(s):  
Yoshiko KOSUGI ◽  
Sumiji KOBASHI
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Net Assimilation Rate ◽  
Assimilation Rate ◽  
Determining Factors ◽  
Use Efficiency ◽  
Alpha Beta ◽  
Net Assimilation

Leaf gas exchange of 11 species of fruit crops with reference to sun-tracking/non-sun-tracking responses

1991 ◽  
Vol 71 (4) ◽  
pp. 1183-1193 ◽  
Author(s):  
Peter C. Andersen
Keyword(s):  
Water Vapor ◽  
Gas Exchange ◽  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Leaf Gas Exchange ◽  
Assimilation Rate ◽  
Fruit Crops ◽  
Use Efficiency ◽  
Ambient Levels

Leaf gas exchange of 11 species of fruit crops supplied with nonlimiting soil moisture was measured under varying levels of irradiance. In full sunlight net CO2 assimilation (A) and stomatal conductance to water vapor (gs) were highest (A = 16.4 μmol m−2 s−1, gs = 455 mmol m−2 s−1) for pecan, intermediate to high (A = 12.1 to 14.6 μmol m−2 s−1, gs = 230 to 370 mmol m−2 s−1) for peach, apple, pear, grape, blackberry and fig, and low (A = 5.7 to 10.2 μmol m−2 s−1, gs < 220 mmol m−2 s−1) for Satsuma, persimmon, blueberry and kiwi. Shadecloth was used to apply 80-s reductions in irradiance in the sequence 100, 66, 33, and 10% full sun. For all species A declined rapidly, yet gs was not altered. Transpiration rate (E) declined slightly, and water use efficiency (WUE) was often near zero at 10% sun. Intercellular CO2 concentration (Ci) was 199 to 237 μmol mol−1 in full sun, but rose to near ambient levels with increased shading. Upon re-exposure to full sun A, gs, E, WUE, and Ci returned to pretreatment levels within 1 min for all species. Interior canopy leaves of pecan, peach, apple, and grape exposed to prolonged periods of low irradiance manifested greater reductions in A than gs or E, hence, WUE was lower and Ci was higher than for sun-exposed leaves. In addition, pecan leaves shaded (33% full sun) for 54 min manifested 50 and 25% reductions in A and gs, respectively. These data indicate that the 11 species under well-watered conditions may be classified as "non-sun tracking". Key words: Intercellular CO2 concentration, leaf conductance, net CO2 assimilation rate, transpiration rate, water use efficiency

Potential yield and water-use efficiency benefits in sorghum from limited maximum transpiration rate

2005 ◽  
Vol 32 (10) ◽  
pp. 945 ◽  
Author(s):  
Thomas R. Sinclair ◽  
Graeme L. Hammer ◽  
Erik J. van Oosterom
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Simulation Analysis ◽  
Stomatal Closure ◽  
Risk Attitude ◽  
Potential Yield ◽  
Yield Increase ◽  
Use Efficiency ◽  
Yield Responses

Limitations on maximum transpiration rates, which are commonly observed as midday stomatal closure, have been observed even under well-watered conditions. Such limitations may be caused by restricted hydraulic conductance in the plant or by limited supply of water to the plant from uptake by the roots. This behaviour would have the consequences of limiting photosynthetic rate, increasing transpiration efficiency, and conserving soil water. A key question is whether the conservation of water will be rewarded by sustained growth during seed fill and increased grain yield. This simulation analysis was undertaken to examine consequences on sorghum yield over several years when maximum transpiration rate was imposed in a model. Yields were simulated at four locations in the sorghum-growing area of Australia for 115 seasons at each location. Mean yield was increased slightly (5–7%) by setting maximum transpiration rate at 0.4 mm h–1. However, the yield increase was mainly in the dry, low-yielding years in which growers may be more economically vulnerable. In years with yield less than ∼450 g m–2, the maximum transpiration rate trait resulted in yield increases of 9–13%. At higher yield levels, decreased yields were simulated. The yield responses to restricted maximum transpiration rate were associated with an increase in efficiency of water use. This arose because transpiration was reduced at times of the day when atmospheric demand was greatest. Depending on the risk attitude of growers, incorporation of a maximum transpiration rate trait in sorghum cultivars could be desirable to increase yields in dry years and improve water use efficiency and crop yield stability.

Effect of drought stress on residual transpiration and its relationship with water use of wheat

1991 ◽  
Vol 71 (3) ◽  
pp. 695-702 ◽  
Author(s):  
J. M. Clarke ◽  
R. A. Richards ◽  
A. G. Condon
Keyword(s):  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Osmotic Potential ◽  
Water Status ◽  
Yield Potential ◽  
Cuticular Transpiration ◽  
Stress Treatment ◽  
Use Efficiency ◽  
Residual Transpiration

Increasing the water use efficiency (WUE) of wheat (Triticum spp.) has long been a goal in semiarid areas. Low rates of residual (cuticular) transpiration are thought to improve yield potential of wheat under dry conditions, although the linkage is tenuous. The objective of this work was to investigate the association of residual transpiration with water use, WUE, and leaf water status in hexaploid (T. aestivum L.) and tetraploid (T. turgidum L. var. durum) genotypes grown under two watering regimes in two glasshouse experiments. Single plants were grown in 0.1-m × 1-m (0.1-m × 0.5-m in exp. 2 low-stress treatment) PVC tubes filled with soil. The watering regimes consisted of weekly replenishment of water used (low stress), or addition of sufficient water to ensure plant survival (high stress). At anthesis, flag leaf residual transpiration (rate of water loss from excised leaves), stomatal conductance, relative water content (RWC), and osmotic potential (exp. 1 only) were measured. Water use was not correlated with residual transpiration rate in either experiment. Residual transpiration rate did not differ for the two stress treatments in exp. 1, but there were significant (P < 0.01) genotype by stress treatment interactions. Residual transpiration rate was not related to plant water status (leaf RWC or osmotic potential) as had been reported in other studies. Key words: Cuticular transpiration, water use efficiency, Triticum aestivum L., Triticum turgidum L. var. durum

Influence of biochar and microorganisms co-application on the remediation and maize productivity in cadmium-contaminated soil.

2021 ◽  
Author(s):  
Fasih Ullah Haider ◽  
Muhammad Farooq ◽  
Muhammad Naveed ◽  
Sardar Alam Cheema ◽  
Noor ul Ain ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Synergistic Effects ◽  
Photosynthesis Rate ◽  
Cow Manure ◽  
Cd Uptake ◽  
Spad Value ◽  
Use Efficiency

Abstract The synergistic effects of biochar and microorganisms on the adsorption of Cd and on cereal plant physiology remained unclear. Therefore, this experiment was performed to evaluate the combined effects of biochar pyrolyzed from (maize-straw (BC1), cow-manure (BC2), and poultry-manure (BC3), and microorganisms including (T. harzianum L. and B. subtilis L.), to evaluate, how incorporation of biochar positively influences microorganisms growth and nutrients uptake in plant, and how it mitigates under various Cd-stress levels (0, 10, and 30ppm). Cd2 (30 ppm) had the highest reduction in the intercellular CO2, SPAD value, transpiration rate, water use efficiency, stomatal conductance, and photosynthesis rate, which were 22.36, 34.50, 40.45, 20.66, 29.07, and 22.41% respectively lower than control Cd0 (0 ppm). Sole application BC, resulted in enhanced intercellular CO2, SPAD value, transpiration rate, water use efficiency, stomatal conductance, and photosynthesis rate were recorded in BC2, which were 7.27, 20.54, 23.80, 5.96, 13.37, and 13.50% respectively greater as compared to control and decreased the Cd-concentration in root and shoot of maize by 34.07 and 32.53%, respectively as compared to control. Similarly, among sole microorganism’s inoculation, minimized the Cd-concentration in shoot, root, and soil by 23.77, 20.15, and 10.35% respectively than control. These results suggested that integrated application of cow manure biochar BC2 and inoculation of microorganisms MI3 as soil amendments had synergistic effects in improving the adsorption of nutrients and decreasing the Cd-uptake in maize, and enhancing the physiology of plant grown in Cd-polluted soils as opposed to using either biochar or inoculating microorganisms alone.

Diurnal Time Course of Leaf Gas Exchange Rates and Related Characters in Drought-Acclimated and Irrigated Trifolium Subterraneum.

1995 ◽  
Vol 22 (3) ◽  
pp. 461 ◽  
Author(s):  
J Vadell ◽  
C Cabot ◽  
H Medrano
Keyword(s):  
Gas Exchange ◽  
Exchange Rates ◽  
Water Use Efficiency ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Trifolium Subterraneum ◽  
Co2 Assimilation ◽  
Carbon Gain ◽  
Assimilation Rate ◽  
Use Efficiency

The effects of drought acclimation on the diurnal time courses of photosynthesis and related characters were studied in Trifolium subterraneum L. leaves during two consecutive late spring days. Leaf CO2 assimilation rate and transpiration rate followed irradiance variations in irrigated plants. Under drought, a bimodal pattern of leaf CO2 assimilation rate developed although stomatal conductance remained uniform and low. Instantaneous water-use efficiency was much higher in droughted plants during the early morning and late evening, while during the middle of the day it was close to the value of irrigated plants. Net carbon gain in plants under drought reached 40% of the carbon gain in irrigated plants with a significant saving of water (80%). Average data derived from midday values of leaf CO2 assimilation rates and instantaneous water-use efficiency did not provide good estimates of the daily carbon gain and water-use efficiency for droughted leaves. Coupled with the morphological changes as a result of acclimation to progressive drought, modifications of diurnal patterns of leaf gas exchange rates effectively contribute to a sustained carbon gain during drought. These modifications significantly improve water-use efficiency, mainly by enabling the plant to take advantage of morning and evening hours with high air humidity.

Response of wheat growth and CO2 assimilation to altering root-zone temperature

1990 ◽  
Vol 68 (12) ◽  
pp. 2698-2702 ◽  
Author(s):  
S. H. Al-Hamdani ◽  
G. W. Todd ◽  
D. A. Francko
Keyword(s):  
Water Use Efficiency ◽  
Water Potential ◽  
Water Use ◽  
Root Zone ◽  
Soluble Sugar ◽  
Leaf Conductance ◽  
Assimilation Rate ◽  
Root Zone Temperature ◽  
Use Efficiency ◽  
Zone Temperature

Wheat plants (Triticum aestivum L. var. Chisholm) grown at an air temperature of 23 °C and a root-zone temperature of 3 °C exhibited a significant reduction in shoot and root dry weight and leaf area compared with plants grown at a root-zone temperature of 23 °C. This reduction was correlated with a significantly lower CO2 assimilation rate that was associated with lower leaf conductance, lower internal CO2 concentration, and more negative water potential. Low CO2 assimilation rate was also associated with high starch and total soluble sugar levels in the shoot, less translocation of photosynthate, and possibly less sink demand. Leaf chlorophyll concentration was not affected by altering the root-zone temperature, whereas water use efficiency of plants grown at a root-zone temperature of 3 °C was as much as 1.5 times higher as those grown at 23 °C. Key words: carbohydrate, chlorophyll, photosynthate partitioning, leaf conductance, water potential, water use efficiency.

EFFICIENCY OF THE USE OF WATER BY THE LEAVES OF SOY PLANTS: TRADITIONS AND NEW CRITERIA

2018 ◽  
Vol 1 (11(56)) ◽  
pp. 42-46
Author(s):  
O.A. Harchuk ◽  
A.F. Kirillov ◽  
A.B. Budak
Keyword(s):  
Water Supply ◽  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Field Level ◽  
Photosyn Thesis ◽  
Use Efficiency ◽  
Soybean Plants ◽  
Soybean Leaves ◽  
New Criteria

The aim of the study was to assess the traditional and new criteria for evaluating water use efficiency (WUE) of soybean leaves by comparing different parameters from instantaneous measurements (WUEi) with the WUE at the field level, as well as studying WUEi-parametres in daily dynamics. Studies were performed using photosyn-thesis and transpiration rate monitor PTM-48A to soybean plants (variety Amelina) in pots with sufficient water supply. It was concluded that as close as possible to WUE field value (0,80 g seeds per kg H2O) is the evaluation of the WUEias a ratio of respiration per unit of water transpired. Estimation of leaf WUEiaccording to previously known parameters does not correspond to field level WUE

scholarly journals Brachiaria physiological parameters in agroforestry systems

2017 ◽  
Vol 47 (5) ◽  
Author(s):  
Márcia Vitória Santos ◽  
Evander Alves Ferreira ◽  
Daniel Valadão ◽  
Fabiana Lopes Ramos de Oliveira ◽  
Vitor Diniz Machado ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Water Use Efficiency ◽  
Water Use ◽  
Transpiration Rate ◽  
Agroforestry Systems ◽  
Physiological Parameters ◽  
Tree Crowns ◽  
Full Sunlight ◽  
Use Efficiency ◽  
Plot Design

ABSTRACT: This study aimed to assess the effects of Eucalyptus and maize shading on characteristics related to water use by Brachiaria in agroforestry systems. Treatments were arranged in a split-split-plot design, with plots consisting of different spacing between Eucalyptus plants (12.0×2.0m and 12.0×4.0m), split-plots of different distances between Brachiaria and Eucalyptus (6.0, 4.0, and 2.0m), and split-split-plots of Brachiaria sowing sites (maize row and inter-row). One treatment with Brachiaria under full sunlight was included. Bread grass intercropping in maize inter-rows associated with the densest Eucalyptus spacing and bread grass proximity to Eucalyptus tree crowns adversely affected the stomatal conductance, internal carbon, and transpiration rate of bread grass. Water use efficiency of bread grass intercropped in maize rows decreased, regardless of the Eucalyptus plot design and distance between forages and trees.

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