Can changes in leaf water potential be assessed spectrally?

2011 ◽  
Vol 38 (6) ◽  
pp. 523 ◽  
Author(s):  
Salah Elsayed ◽  
Bodo Mistele ◽  
Urs Schmidhalter
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Plant Development ◽  
Water Status ◽  
Leaf Water ◽  
Plant Water Status ◽  
Plant Water ◽  
Development Stages ◽  
Spectrometric Measurements ◽  
Chamber Measurements

Leaf water potential (LWP) is an important indicator of plant water status. However, its determination via classical pressure-chamber measurements is tedious and time-consuming. Moreover, such methods cannot easily account for rapid changes in this parameter arising from changes in environmental conditions. Spectrometric measurements, by contrast, have the potential for fast and non-destructive measurements of plant water status, but are not unproblematic. Spectral characteristics of plants vary across plant development stages and are also influenced by environmental factors. Thus, it remains unclear whether changes in leaf water potential per se can reliably be detected spectrometrically or whether such measurements also reflect autocorrelated changes in the leaf water content (LWC) or the aerial plant biomass. We tested the accuracy of spectrometric measurements in this context under controlled climate chamber conditions in series of six experiments that minimised perturbing influences but allowed for significant changes in the LWP. Short-term exposure of dense stands of plants to increasing or decreasing artificial light intensities in a growth chamber more markedly decreased LWP than LWC in both wheat and maize. Significant relationships (R2-values 0.74–0.92) between LWP and new spectral indices ((R940/R960)/NDVI; R940/R960) were detected with or without significant changes in LWC of both crop species. The exact relationships found, however, were influenced strongly by the date of measurement or water stress induced. Thus, global spectral relationships measuring LWP probably cannot be established across plant development stages. Even so, spectrometric measurements supplemented by a reduced calibration dataset from pressure chamber measurements might still prove to be a fast and accurate method for screening large numbers of diverse lines.

scholarly journals A minimally disruptive method for measuring water potential in planta using hydrogel nanoreporters

2021 ◽  
Vol 118 (23) ◽  
pp. e2008276118
Author(s):  
Piyush Jain ◽  
Weizhen Liu ◽  
Siyu Zhu ◽  
Christine Yao-Yun Chang ◽  
Jeff Melkonian ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Resonance Energy ◽  
Field Measurements ◽  
Leaf Water ◽  
Plant Water Status ◽  
Plant Water ◽  
In Planta

Leaf water potential is a critical indicator of plant water status, integrating soil moisture status, plant physiology, and environmental conditions. There are few tools for measuring plant water status (water potential) in situ, presenting a critical barrier for developing appropriate phenotyping (measurement) methods for crop development and modeling efforts aimed at understanding water transport in plants. Here, we present the development of an in situ, minimally disruptive hydrogel nanoreporter (AquaDust) for measuring leaf water potential. The gel matrix responds to changes in water potential in its local environment by swelling; the distance between covalently linked dyes changes with the reconfiguration of the polymer, leading to changes in the emission spectrum via Förster Resonance Energy Transfer (FRET). Upon infiltration into leaves, the nanoparticles localize within the apoplastic space in the mesophyll; they do not enter the cytoplasm or the xylem. We characterize the physical basis for AquaDust’s response and demonstrate its function in intact maize (Zea mays L.) leaves as a reporter of leaf water potential. We use AquaDust to measure gradients of water potential along intact, actively transpiring leaves as a function of water status; the localized nature of the reporters allows us to define a hydraulic model that distinguishes resistances inside and outside the xylem. We also present field measurements with AquaDust through a full diurnal cycle to confirm the robustness of the technique and of our model. We conclude that AquaDust offers potential opportunities for high-throughput field measurements and spatially resolved studies of water relations within plant tissues.

scholarly journals A minimally disruptive method for measuring water potential in-planta using hydrogel nanoreporters

2020 ◽  
Author(s):  
Piyush Jain ◽  
Weizhen Liu ◽  
Siyu Zhu ◽  
Jeff Melkonian ◽  
Duke Pauli ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Resonance Energy ◽  
Field Measurements ◽  
Leaf Water ◽  
Plant Water Status ◽  
Plant Water ◽  
In Planta

AbstractLeaf water potential is a critical indicator of plant water status, integrating soil moisture status, plant physiology, and environmental conditions. There are few tools for measuring plant water status (water potential) in situ, presenting a critical barrier for the development of appropriate phenotyping (measurement) methods for crop development and modeling efforts aimed at understanding water transport in plants. Here, we present the development of an in situ, minimally-disruptive hydrogel nanoreporter (AquaDust) for measuring leaf water potential. The gel matrix responds to changes in water potential in its local environment by swelling; the distance between covalently linked dyes changes with the reconfiguration of the polymer, leading to changes in the emission spectrum via Fluorescence Resonance Energy Transfer (FRET). Upon infiltration into leaves, the nanoparticles localize within the apoplastic space in the mesophyll; they do not enter the cytoplast or the xylem. We characterize the physical basis for AquaDust’s response and demonstrate its function in intact maize (Zea mays L.) leaves as a reporter of leaf water potential. We use AquaDust to measure gradients of water potential along intact, actively transpiring leaves as a function of water status; the localized nature of the reporters allows us to define a hydraulic model that distinguishes resistances inside and outside the xylem. We also present field measurements with AquaDust through a full diurnal cycle to confirm the robustness of the technique and of our model. We conclude that AquaDust offers potential opportunities for high-throughput, field measurements and spatially resolved studies of water relations within plant tissues.

scholarly journals Arbuscular Mycorrhiza Symbiosis Enhances Water Status and Soil-Plant Hydraulic Conductance Under Drought

2021 ◽  
Vol 12 ◽  
Author(s):  
Mohanned Abdalla ◽  
Mutez Ali Ahmed
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Hydraulic Conductance ◽  
Leaf Water ◽  
Plant Water Status ◽  
Soil Drying ◽  
Plant Water ◽  
Matric Potential ◽  
Soil Interface

Recent studies have identified soil drying as a dominant driver of transpiration reduction at the global scale. Although Arbuscular Mycorrhiza Fungi (AMF) are assumed to play a pivotal role in plant response to soil drying, studies investigating the impact of AMF on plant water status and soil-plant hydraulic conductance are lacking. Thus, the main objective of this study was to investigate the influence of AMF on soil-plant conductance and plant water status of tomato under drought. We hypothesized that AMF limit the drop in matric potential across the rhizosphere, especially in drying soil. The underlying mechanism is that AMF extend the effective root radius and hence reduce the water fluxes at the root-soil interface. The follow-up hypothesis is that AMF enhance soil-plant hydraulic conductance and plant water status during soil drying. To test these hypotheses, we measured the relation between transpiration rate, soil and leaf water potential of tomato with reduced mycorrhiza colonization (RMC) and the corresponding wild type (WT). We inoculated the soil of the WT with Rhizophagus irregularis spores to potentially upsurge symbiosis initiation. During soil drying, leaf water potential of the WT did not drop below −0.8MPa during the first 6days after withholding irrigation, while leaf water potential of RMC dropped below −1MPa already after 4days. Furthermore, AMF enhanced the soil-plant hydraulic conductance of the WT during soil drying. In contrast, soil-plant hydraulic conductance of the RMC declined more abruptly as soil dried. We conclude that AMF maintained the hydraulic continuity between root and soil in drying soils, hereby reducing the drop in matric potential at the root-soil interface and enhancing soil-plant hydraulic conductance of tomato under edaphic stress. Future studies will investigate the role of AMF on soil-plant hydraulic conductance and plant water status among diverse plant species growing in contrasting soil textures.

scholarly journals Evaluation of Alnus subcordata for urban environments through assessment of drought and flooding tolerance

Dendrobiology ◽  
2021 ◽  
Vol 85 ◽  
pp. 39-50
Author(s):  
Henrik Sjöman ◽  
Anna Levinsson ◽  
Tobias Emilsson ◽  
Aida Ibrahimova ◽  
Valida Alizade ◽  
...  
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Urban Environments ◽  
Leaf Water ◽  
Plant Water Status ◽  
Plant Water ◽  
Drought Treatment ◽  
Significant Difference ◽  
Alnus Subcordata

The urban environment is stressful and trees experience multiple stresses, including drought, flooding, and extreme heat, all of which are likely to increase under future climate warming and increasing urbanisation. In the selection of tree species to maximise ecosystem services, tolerance to site characteristics such as flooding and severe drought is of critical importance. This study evaluated the suitability of a rare species, Alnus subcordata C.A. Mey (Caucasian alder) from the Hyrcanian forests of southern Azerbaijan,for its functionality as an urban tree. A total of 48 pot-grown, two-year-old saplings of A. subcordata were tested in a greenhouse experiment using a complete randomised block design. Each block contained four replicates of three treatments (waterlogging, drought, control), with 16 plants per treatment. Height differences between treatments were measured, and water status was estimated by determination of midday leaf water potential (ΨL) and stomatal conductance (gs). To estimate drought tolerance reaction in the treatments, leaf water potential at turgor loss (ΨP0) was used together with broken-stick modelling of water status over time. There was a significant difference in tree height between the different treatments. In the drought treatment, A. subcordata plants showed no height increase, while plants in both the waterlogged and control treatments increased in height during the nine-week experiment. Over 63 days of flooding, plant water status was slightly more negative in the waterlogging treatment, but did not deviate essentially from the control. In the drought treatment, plant water status rapidly deviated from the control. There was a significant differencein ΨP0 between treatments, with drought-treated plants showing the lowest value (−2.31 MPa).This study demonstrated that A. subcordata has limited tolerance to drought and seems to rely more on waterloss-avoiding strategies. However, the species may be usable at periodically waterlogged sites, due to its high tolerance to flooding. It could therefore be recommended for wet urban environments and stormwater management facilities, for which reliable guidance on suitable trees is currently lacking.

Branch water potential; a useful indicator of plant water potential in comparison to leaf water potential in canola

2000 ◽  
Vol 40 (5) ◽  
pp. 687 ◽  
Author(s):  
A. L. Bernardi
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Source Material ◽  
Leaf Water ◽  
Moisture Loss ◽  
Plant Water ◽  
Portable Equipment ◽  
Plant Water Potential ◽  
Main Growth

The water potentials of canola branches and leaves were compared using a pressure chamber to determine whether they produced similar results. This study also investigated the magnitude of errors in the water status of canola resulting from re-cutting the branches, and the effects of delaying readings. The use of branches containing pods or pods and flowers/buds gave very good correlation with leaves. As this is the area of greatest photosynthesis and transpiration from mid-flowering, it provides an easily obtainable source material close to the main growth areas to measure plant water potential. Storage of both leaves and stems before measurement is an acceptable procedure if a large number of samples are required to be completed or portable equipment is not available provided precautions are taken to prevent moisture loss. Re-cutting the branch leads to lower water potential and should be avoided.

Photosynthesis in Coffea arabica. II. Effects of Water Stress

1980 ◽  
Vol 16 (1) ◽  
pp. 21-27 ◽  
Author(s):  
D. Kumar ◽  
Larry L. Tieszen
Keyword(s):  
Soil Moisture ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Coffea Arabica ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Plant Water

SUMMARYExperiments were carried out to relate soil moisture to leaf water potential (Ψ1), and to determine the effects of varying Ψ1, on leaf conductances and photosynthesis in coffee. Stomatal conductance was maximum at 0900 h, but plants growing in drier soil showed marked mid-day stomatal closure. After 1500 h, stomata began closing although plant water status improved. Photosynthesis in relation to changing Ψ1 appeared to exhibit roughly three different rates. At the fixed experimental temperature (25°C) low Ψ1 reduced photosynthesis throughits influence on stomata, but under field conditions low Ψ1 and an accompanying rise in temperature could lower the rate by lowering both mesophyll and stomatal conductances.

Visual estimation of plant water status in cereals

1979 ◽  
Vol 92 (1) ◽  
pp. 83-89 ◽  
Author(s):  
H. G. Jones
Keyword(s):  
Spring Wheat ◽  
Water Status ◽  
Plant Morphology ◽  
Leaf Water ◽  
Plant Water Status ◽  
Plant Water ◽  
Visual Estimation ◽  
Leaf Water Status ◽  
Visual Scoring ◽  
Breeding Programmes

SummaryThe potential offered for plant breeding programmes by visual scoring techniques for plant water status was investigated in rice and spring wheat. It was found that differing plant morphology could seriously bias visual estimates of leaf water potential, particularly in spring wheat. In spite of this problem, it was found that at least for rice, this type of approach may have potential in future breeding programmes where an estimate of leaf water status is required, such as those for drought tolerance, so long as a high intensity of selection is not necessary.

THE WATER RELATIONS AND IRRIGATION REQUIREMENTS OF COCONUT (Cocos nucifera): A REVIEW

2011 ◽  
Vol 47 (1) ◽  
pp. 27-51 ◽  
Author(s):  
M. K. V. CARR
Keyword(s):  
Water Potential ◽  
Water Use ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Water Productivity ◽  
Chloride Ions ◽  
Leaf Water ◽  
Flower Initiation ◽  
Plant Water ◽  
Drought Mitigation

SUMMARYThe results of research on the water relations and irrigation needs of coconut are collated and summarized in an attempt to link fundamental studies on crop physiology to drought mitigation and irrigation practices. Background information on the centres of origin and production of coconut and on crop development processes is followed by reviews of plant water relations, crop water use and water productivity, including drought mitigation. The majority of the recent research published in the international literature has been conducted in Brazil, Kerala (South India) and Sri Lanka, and by CIRAD (France) in association with local research organizations in a number of countries, including the Ivory Coast. The unique vegetative structure of the palm (stem and leaves) together with the long interval between flower initiation and the harvesting of the mature fruit (44 months) mean that causal links between environmental factors (especially water) are difficult to establish. The stomata play an important role in controlling water loss, whilst the leaf water potential is a sensitive indicator of plant water status. Both stomatal conductance and leaf water potential are negatively correlated with the saturation deficit of the air. Although roots extend to depths >2 m and laterally >3 m, the density of roots is greatest in the top 0–1.0 m soil, and laterally within 1.0–1.5 m of the trunk. In general, dwarf cultivars are more susceptible to drought than tall ones. Methods of screening for drought tolerance based on physiological traits have been proposed. The best estimates of the actual water use (ETc) of mature palms indicate representative rates of about 3 mm d−1. Reported values for the crop coefficient (Kc) are variable but suggest that 0.7 is a reasonable estimate. Although the sensitivity of coconut to drought is well recognized, there is a limited amount of reliable data on actual yield responses to irrigation although annual yield increases (50%) of 20–40 nuts palm−1 (4–12 kg copra, cultivar dependent) have been reported. These are only realized in the third and subsequent years after the introduction of irrigation applied at a rate equivalent to about 2 mm d−1 (or 100 l palm−1 d−1) at intervals of up to one week. Irrigation increases female flower production and reduces premature nut fall. Basin irrigation, micro-sprinklers and drip irrigation are all suitable methods of applying water. Recommended methods of drought mitigation include the burial of husks in trenches adjacent to the plant, mulching and the application of common salt (chloride ions). An international approach to addressing the need for more information on water productivity is recommended.

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