Conservative water use under high evaporative demand associated with smaller root metaxylem and limited trans-membrane water transport in wheat

2014 ◽  
Vol 41 (3) ◽  
pp. 257 ◽  
Author(s):  
Rémy Schoppach ◽  
Diego Wauthelet ◽  
Linda Jeanguenin ◽  
Walid Sadok
Keyword(s):  
Water Use ◽  
Cross Sections ◽  
Water Conservation ◽  
Vapour Pressure Deficit ◽  
Differential Sensitivity ◽  
Mercury Chloride ◽  
Evaporative Demand ◽  
Physiological Basis ◽  
Drought Tolerant ◽  
Efficient Breeding

Efficient breeding of drought-tolerant wheat (Triticum spp.) genotypes requires identifying mechanisms underlying exceptional performances. Evidence indicates that the drought-tolerant breeding line RAC875 is water-use conservative, limiting its transpiration rate (TR) sensitivity to increasing vapour pressure deficit (VPD), thereby saving soil water moisture for later use. However, the physiological basis of the response remains unknown. The involvement of leaf and root developmental, anatomical and hydraulic features in regulating high-VPD, whole-plant TR was investigated on RAC875 and a drought-sensitive cultivar (Kukri) in 12 independent hydroponic and pot experiments. Leaf areas and stomatal densities were found to be identical between lines and de-rooted plants didn’t exhibit differential TR responses to VPD or TR sensitivity to four aquaporin (AQP) inhibitors that included mercury chloride (HgCl2). However, intact plants exhibited a differential sensitivity to HgCl2 that was partially reversed by β-mercaptoethanol. Further, root hydraulic conductivity of RAC875 was found to be lower than Kukri’s and root cross-sections of RAC875 had significantly smaller stele and central metaxylem diameters. These findings indicate that the water-conservation of RAC875 results from a root-based hydraulic restriction that requires potentially heritable functional and anatomical features. The study revealed links between anatomical and AQP-based processes in regulating TR under increasing evaporative demand.

A Physiological Comparison of Leaves and Phyllodes in Acacia melanoxylon

1993 ◽  
Vol 41 (3) ◽  
pp. 293 ◽  
Author(s):  
T Brodribb ◽  
RS Hill
Keyword(s):  
Water Stress ◽  
Water Use Efficiency ◽  
Water Use ◽  
Vapour Pressure Deficit ◽  
High Irradiance ◽  
Short Term ◽  
Evaporative Demand ◽  
Wide Range ◽  
Use Efficiency ◽  
Stomatal Sensitivity

Leaves and phyllodes of A. melanoxylon were compared in several aspects of their physiology. Changes in gas exchange and water use efficiency (WUE) under controlled conditions of vapour pressure deficit (vpd) and foliar water potential were examined. Water use efficiency in phyllodes remained constant under a wide range of evaporative demand due to high stomatal sensitivity to vpd. Leaf stomata were less sensitive to changes in vpd causing decreased WUE with increased vpd. Under water stress phyllodes survived longer and produced higher WUE than leaves. Maximum photosynthetic rates per unit foliar area were higher in phyllodes than leaves. Thus, phyllodes have a number of advantages over leaves under conditions of long and short term water stress and high irradiance. Leaves had a higher photosynthetic rate per unit of photosynthetic investment than phyllodes, suggesting that their function is to maximise growth during the seedling phase.

scholarly journals Estimation of Daily Water Requirements for Potted Ornamental Crops

1992 ◽  
Vol 2 (4) ◽  
pp. 454-456
Author(s):  
C.D. Stanley ◽  
B.K. Harbaugh
Keyword(s):  
Plant Species ◽  
Water Use ◽  
Water Conservation ◽  
Growth Habit ◽  
Prediction Equations ◽  
Evaporative Demand ◽  
Water Requirements ◽  
Daily Water ◽  
Input Variables ◽  
Growing Conditions

Methodology was developed to estimate water requirements for production of 20 different potted ornamental plant species with practical application for water conservation in commercial operations. Water requirement prediction equations were generated using pan evaporation to estimate evaporative demand along with plant canopy height and width and flower height as input variables. Coefficients of determination (R2) for the prediction equations among plant species ranged from 0.51 to 0.91, with the lower values mostly associated with plant species with an open or less-uniform growth habit. Variation in water use among different cultivars of marigold also was associated with differences in cultivar growth habit. Estimation of the daily water requirements of potted Reiger begonia and Ficus benjamina using their developed prediction equations was compared to actual water use under common growing conditions to demonstrate the implementation of the method for plant species differing in growth habit.

scholarly journals Water Conservation in the Urban Landscape

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 549E-549
Author(s):  
Roger Kjelgren ◽  
Larry Rupp
Keyword(s):  
Water Use ◽  
Water Conservation ◽  
Woody Plants ◽  
Urban Landscape ◽  
Reference Evapotranspiration ◽  
Stomatal Closure ◽  
Pressure Gradients ◽  
Evaporative Demand ◽  
Landscape Water ◽  
Peak Summer

As populations become increasingly urbanized, landscape water conservation becomes more important. Landscape water consumption can increase municipal water use up to 4-fold during the growing season, and account for half the total yearly water use. Landscape water conservation is important in decreasing peak summer water demand to reduce the strain on delivery systems, and to reduce total demand so that development of new sources can be forestalled. Potential water savings from existing landscapes can be estimated by comparing historical usage gleaned from water meter readings to plant water needs estimated from reference evapotranspiration. Estimating water needs for turf is straightforward because of the few species involved and the uniformity of turf landscapes. Estimating water needs of woody plants is more difficult because of the heterogeneity of woody plants and how they are used, and woody plants respond to evaporative demand differently than turfgrass. Many woody plants will actually use less water as reference evapotranspiration increases due to stomatal closure induced by high leaf-air vapor pressure gradients. Landscape water is then conserved by either applying water more effectively in scheduling when and how long to irrigate based on estimating water use again from reference evapotranspiration, or by replacing areas in turfgrass with plants more-adapted to the existing conditions. Encouraging water conservation by end users is the final and largest challenge. Automated irrigation systems makes wasting water easy, while conserving water takes more effort. Education is the key to successful landscape water conservation.

The implications of climate change on residential water use: a micro-scale analysis of Portland (OR), USA

2012 ◽  
Vol 3 (3) ◽  
pp. 225-238 ◽  
Author(s):  
Vivek Shandas ◽  
Meenakshi Rao ◽  
Moriah McSharry McGrath
Keyword(s):  
Climate Change ◽  
Water Use ◽  
Environmental Sustainability ◽  
Water Conservation ◽  
Urban Areas ◽  
Future Climate ◽  
Metropolitan Region ◽  
Study Region ◽  
Residential Water Use ◽  
Residential Water

Social and behavioral research is crucial for securing environmental sustainability and improving human living environments. Although the majority of people now live in urban areas, we have limited empirical evidence of the anticipated behavioral response to climate change. Using empirical data on daily household residential water use and temperature, our research examines the implications of future climate conditions on water conservation behavior in 501 households within the Portland (OR) metropolitan region. We ask whether and how much change in ambient temperatures impact residential household water use, while controlling for taxlot characteristics. Based on our results, we develop a spatially explicit description about the changes in future water use for the study region using a downscaled future climate scenario. The results suggest that behavioral responses are mediated by an interaction of household structural attributes, and magnitude and temporal variability of weather parameters. These findings have implications for the way natural resource managers and planning bureaus prepare for and adapt to future consequences of climate change.

Water Requirements and Conservation Alternatives for Northern Communities

1983 ◽  
Vol 15 (S2) ◽  
pp. 65-93 ◽  
Author(s):  
B C Armstrong ◽  
D W Smith ◽  
J J Cameron
Keyword(s):  
Water Use ◽  
Water Conservation ◽  
Basic Needs ◽  
Economic Aspects ◽  
Water Requirements ◽  
Rate Structure ◽  
Individual Household

This paper reviews water requirements and the alternatives for water conservation in small, relatively remote northern communities. Requirements are examined in terms of basic needs and desires for sanitation from an individual household and a community perspective. Presented are factors which influence water use such as the method of delivery, household plumbing, socio-economic aspects, rate structure, climate and plumbing codes. Similarly, factors which influence water conservation are identified. Outlined in detail are current methods of reducing water use within the northern household.

scholarly journals The contribution of PIP2-type aquaporins to photosynthetic response to increased vapour pressure deficit

2021 ◽  
Author(s):  
D Israel ◽  
S Khan ◽  
C R Warren ◽  
J J Zwiazek ◽  
T M Robson
Keyword(s):  
Vapour Pressure Deficit ◽  
Air Humidity ◽  
Wild Type ◽  
Knockout Mutant ◽  
Evaporative Demand ◽  
Co2 Transport ◽  
Whole Plant ◽  
Knockout Mutants ◽  
Leaf Level ◽  
Low Humidity

Abstract The roles of different plasma membrane aquaporins (PIPs) in leaf-level gas exchange of Arabidopsis thaliana were examined using knockout mutants. Since multiple Arabidopsis PIPs are implicated in CO2 transport across cell membranes, we focused on identifying the effects of the knockout mutations on photosynthesis, and whether they are mediated through the control of stomatal conductance of water vapour (gs), mesophyll conductance of CO2 (gm) or both. We grew Arabidopsis plants in low and high humidity environments and found that the contribution of PIPs to gs was larger under low air humidity when the evaporative demand was high, whereas any effect of lacking PIP function was minimal under higher humidity. The pip2;4 knockout mutant had 44% higher gs than the wild type plants under low humidity, which in turn resulted in an increased net photosynthetic rate (Anet). We also observed a 23% increase in whole-plant transpiration (E) for this knockout mutant. The lack of functional AtPIP2;5 did not affect gs or E, but resulted in homeostasis of gm despite changes of humidity, indicating a possible role in regulating CO2 membrane permeability. CO2 transport measurements in yeast expressing AtPIP2;5 confirmed that this aquaporin is indeed permeable to CO2.

scholarly journals The physiological basis for genetic variation in water use efficiency and carbon isotope composition in Arabidopsis thaliana

2013 ◽  
Vol 119 (1-2) ◽  
pp. 119-129 ◽  
Author(s):  
Hsien Ming Easlon ◽  
Krishna S. Nemali ◽  
James H. Richards ◽  
David T. Hanson ◽  
Thomas E. Juenger ◽  
...  
Keyword(s):  
Arabidopsis Thaliana ◽  
Genetic Variation ◽  
Water Use Efficiency ◽  
Carbon Isotope ◽  
Water Use ◽  
Isotope Composition ◽  
Carbon Isotope Composition ◽  
Physiological Basis ◽  
Use Efficiency

Improving efficiency in water use and conservation in Spanish hotels

2005 ◽  
Vol 5 (3-4) ◽  
pp. 273-279 ◽  
Author(s):  
R. Cobacho ◽  
F. Arregui ◽  
J.C. Parra ◽  
E. Cabrera
Keyword(s):  
Water Management ◽  
Water Use ◽  
Water Conservation ◽  
Fundamental Component ◽  
Conservation Actions ◽  
Water Scarce

Hotels are a fundamental component within the tourist Spanish sector, and their role in water management turns out even more relevant taking into account the fact that tourist areas, in which they are generally located, are water scarce. Trying to go further from the standard ratios and estimations to plan water conservation, this work intends to really measure and quantify water use in rooms. Only by doing this, can subsequent conservation actions, now able to be reliably specified for each specific use, achieve a real success.

Impact assessment of climate change and human activities on GHG emissions and agricultural water use

2021 ◽  
Author(s):  
Shikun Sun ◽  
Yihe Tang
Keyword(s):  
Climate Change ◽  
Water Use ◽  
Water Conservation ◽  
Positive Impact ◽  
Ghg Emissions ◽  
Production Factor ◽  
Agricultural Water ◽  
Dndc Model ◽  
Agricultural Water Use ◽  
Means Of Production

<p>The agriculture sector is one of the largest users of water and a significant source of greenhouse gas (GHG) emissions. The development of low-GHG-emission and water-conserving agriculture will inevitably be the trend in the future. Because of the physiological differences among crops and their response efficiency to external changes, changes in planting structure, climate and input of production factors will have an impact on regional agricultural water use and GHG emissions. This paper systematically analyzed the spatial-temporal evolution characteristics of crop planting structure, climate, and production factor inputs in Heilongjiang Province, the main grain-producing region of China, from 2000 to 2015, and quantified the regional agricultural water use and GHG emissions characteristics under different scenarios by using the Penman-Monteith formula and the Denitrification-Decomposition (DNDC) model. The results showed that the global warming potential (GWP) increased by 15% due to the change in planting structure. A large increase in the proportion of rice and corn sown was the main reason. During the study period, regional climate change had a positive impact on the water- saving and emission reduction of the agricultural industry. The annual water demand per unit area decreased by 19%, and the GWP decreased by 12% compared with that in 2000. The input of fertilizer and other means of production will have a significant impact on GHG emissions from farmlands. The increase in N fertilizer input significantly increased N<sub>2</sub>O emissions, with a 5% increase in GWP. Agricultural water consumption and carbon emissions are affected by changes in climate, input of means of production, and planting structure. Therefore, multiple regulatory measures should be taken in combination with regional characteristics to realize a new layout of planting structure with low emissions, water conservation, and sustainability.</p>

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