Errors Arising From Rapid Water Loss in the Measurement of Leaf Water Potential by the Pressure Chamber Technique

1980 ◽  
Vol 7 (5) ◽  
pp. 527 ◽  
Author(s):  
NC Turner ◽  
MJ Long
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Loss ◽  
Water Retention ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Diurnal Changes ◽  
Water Potentials ◽  
Retention Characteristics ◽  
Flow Through

In rapidly transpiring leaves, the water potentials of uncovered leaves measured in a pressure chamber were 0.2-0.7 MPa lower than the water potentials of leaves that were covered with a plastic sheath from just prior to their excision to the completion of the measurement. The error in the water potential of uncovered leaves arose from rapid water loss in the first 30 s after excision. The degree to which the water potentials were lowered depended on the rate of transpiration, the leaf water potential at the time of excision, the species, and whether the plants were grown in the glasshouse or field. It is suggested that the variation between species and between glasshouse-grown and field-grown plants arises from differences in water retention characteristics of plant tissue as well as to differences in the rates of transpiration at excision. The size of the error induced by the rapid water loss on diurnal changes in leaf water potential is demonstrated and the effect of the error in the calculation of turgor potentials and in the resistances to water flow through the plant is discussed.

Evaluation of the hydraulic press for measurement of leaf water potentials in cassava

1983 ◽  
Vol 101 (2) ◽  
pp. 407-410 ◽  
Author(s):  
J. A. Palta
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Hydraulic Press ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Moisture Loss ◽  
Total Leaf Area ◽  
Water Potentials ◽  
Wide Range ◽  
Poor Relationship

SUMMARYIn the application of the Scholander pressure chamber technique to cassava water relations studies, the leaf water potential measured on central lobules was initially compared with that measured on entire leaves (including petiole). Measurements made using both a Campbell-Brewster hydraulic press and a pressure chamber of the leaf water potential in six different cassava clones were also compared. Although the central lobules showed a greater sensitivity to moisture loss after sampling than entire leaves, their leaf water potential was in close agreement with those measured on the entire leaves (r3 = 0·96). Therefore, for routine and field estimates in cassava, measurements made on the central lobules may be used to avoid the large reduction in total leaf area. The Campbell-Brewster hydraulic press satisfactorily estimated leaf water potential in M.Col. 1684 clone, which had the longest and narrowest lobules, but in other clones the leaf water potential was overestimated at high leaf potential (> -12·5) and underestimated at low water potentials (< -12·5). Over a wide range of leaf water potentials, a poor relationship between leaf water potentials estimated with hydraulic press and with the pressure chamber was observed for cassava because press estimates are influenced by lobule length and lobule width.

scholarly journals Comparisons of Leaf Water Potential and Xylem Water Potential in tomato Plants

1970 ◽  
Vol 23 (2) ◽  
pp. 485 ◽  
Author(s):  
HD Barrs ◽  
B Freeman ◽  
J Blackwell ◽  
RD Ceccato
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Present Communication ◽  
Pressure Potential ◽  
Xylem Water Potential ◽  
Tomato Plants ◽  
Water Potentials ◽  
Xylem Pressure Potential

The rapidity and convenience of the pressure chamber technique for estimating leaf water potentials, especially under field conditions, has been remarked (Boyer 1967; Kaufmann 1968a, 1968b) and demonstrated (Klepper and Ceccato 1969). However, Kaufmann (1968a) showed that it is necessary to exercise caution .in using measurements made with the pressure chamber as direct estimates of leaf water potential. Instead, he recommended that calibration curves should be drawn up for each species, relating measurements of xylem pressure potential obtained with this technique to corresponding known leaf water potentials. The present communication reports such a relation for tomato leaves, which have not previously been studied in this way. Plant age is shown to affect the relation.

Photosynthesis Response of Sunlit and Shade Pepper (Capsicum annuum) Leaves at Different Positions in the Canopy Under Two Water Regimes

1994 ◽  
Vol 21 (3) ◽  
pp. 377 ◽  
Author(s):  
A Alvino ◽  
M Centritto ◽  
FD Lorenzi
Keyword(s):  
Water Potential ◽  
Capsicum Annuum ◽  
Leaf Water Potential ◽  
Co2 Exchange ◽  
Leaf Water ◽  
Predawn Leaf Water Potential ◽  
Water Regimes ◽  
Water Potentials ◽  
Sun And Shade ◽  
Shade Leaves

Pepper (Capsicum annuum L.) plants were grown in 1 m2 lysimeters under two different water regimes in order to investigate differences in the spatial arrangements of the leaves and to relate this to daily assimilation rates of leaves of the canopy. The control regime (well-watered (W) treatment) was irrigated whenever the accumulated 'A' pan evaporation reached 4 cm, whereas the water-stressed (S) treatment was watered whenever the predawn leaf water potential fell below -1 MPa. During the growing cycle, equal numbers of sun and shade leaves were chosen from the apical, middle and basal parts of the canopy, corresponding to groups of leaves of increasing age. The CO2 exchange rate (CER) was measured at 0830, 1230 and 1530 hours on 8 days along the crop cycle, on leaves in their natural inclination and orientation. Leaf water potentials were measured on apical leaves before dawn and concurrently with gas exchange measurements. Control plants maintained predawn leaf water potential at -0.3 MPa, but S plants reached values lower than -1.2 MPa. Midday leaf water potentials were about twice as low in the S plants as in the controls. Water stress reduced LA1 during the period of crop growth, and dry matter production at harvest. Stressed apical leaves appeared to reduce stress by changing their inclination. They were paraheliotropic around midday and diaheliotropic at 0830 and 1530 hours. The CER values of the S treatment were significantly lower than those of the W treatment in apical and middle leaves, whereas the CER of basal leaves did not differ in either treatments. In the S treatment, reduction in the CER values of sunlit apical leaves was more evident in the afternoon than at midday or early in the morning, whereas basal leaves were less affected by water than basal stress leaves if sunlit, and negligibly in shaded conditions.

Does predawn water potential discern between irrigation treatments in Galician white grapevine cultivars?

OENO One ◽  
2014 ◽  
Vol 48 (2) ◽  
pp. 123 ◽  
Author(s):  
José Manuel Mirás-Avalos ◽  
Emiliano Trigo-Córdoba ◽  
Yolanda Bouzas-Cid
Keyword(s):  
Water Potential ◽  
Leaf Water Potential ◽  
Water Status ◽  
Irrigation Management ◽  
Growing Season ◽  
Climatic Conditions ◽  
Leaf Water ◽  
Diurnal Changes ◽  
Stem Water Potential ◽  
Stem Water

<p style="text-align: justify;"><strong>Aims</strong>: To evaluate the usefulness of predawn water potential (<strong>Ψ</strong><sub>pd</sub>) to assess the water status of Galician grapevine cultivars for irrigation purposes.</p><p style="text-align: justify;"><strong>Methods and results</strong>: Three Galician white grapevine cultivars (Albariño, Godello and Treixadura) were subjected to rain-fed and irrigation conditions during the 2013 growing season. Diurnal changes in leaf water potential (<strong>Ψ</strong><sub>l</sub>) were measured using a pressure chamber on days with high evapotranspiration demand. Stem water potential (<strong>Ψ</strong><sub>s</sub>) was measured at midday. <strong>Ψ</strong><sub>pd</sub> was not able to discriminate between treatments, whereas <strong>Ψ</strong><sub>l</sub> and <strong>Ψ</strong><sub>s</sub> at midday were able to detect significant differences in water status among plants.</p><p style="text-align: justify;"><strong>Conclusion</strong>: <strong>Ψ</strong><sub>pd</sub> was not useful to evaluate vine water status under the Galician climatic conditions. In contrast, both <strong>Ψ</strong><sub>l</sub> and <strong>Ψ</strong><sub>s</sub> were effective for detecting differences between treatments and can thus be used for irrigation management purposes.</p><p style="text-align: justify;"><strong>Significance and impact of the study</strong>: This is the first study evaluating water status of Galician grapevine cultivars. It also provides useful information about the strategy for its control through measurements of midday <strong>Ψ</strong>l or <strong>Ψ</strong>s.</p>

scholarly journals Vine water deficit : among the 3 applications of pressure chamber, stem water potential is the most sensitive indicator

OENO One ◽  
2000 ◽  
Vol 34 (4) ◽  
pp. 169
Author(s):  
Xavier Choné ◽  
Olivier Trégoat ◽  
Cornelis Van Leeuwen ◽  
Denis Dubourdieu
Keyword(s):  
Water Potential ◽  
Water Deficit ◽  
Leaf Water Potential ◽  
Water Status ◽  
Pressure Chamber ◽  
Leaf Water ◽  
Sensitive Indicator ◽  
Stem Water Potential ◽  
Water Deficits ◽  
Stem Water

<p style="text-align: justify;">Vine water status is an important factor in grape quality. High tannin and anthocyanin content in red grape berries are related to moderate vine water deficits. Hence, a simple and sensitive indicator is required to determine vine water status and especially water constraint. Pressure chamber allows a quick and easy to practice determination of water status in the vineyard. Three applications of pressure chamber are known: predawn leaf water potential (ΨB), leaf water potential (ΨF) and stem water potential (ΨT). Only ΨB and ΨF are widely used on vines. In this survey ΨB, ΨF, ΨT and transpiration flow were measured on mature leaves to determine non-irrigated vine water status in field grown vines during the growing season. In California as well as in France, stem Ψ was the most discriminating indicator for both moderate and severe water deficits. In every plot surveyed ΨT was much better correlated to leaf transpiration than ΨF. Moreover, ΨT revealed nascent water deficit earlier than ΨB did. Among the three application of pressure chamber, ΨT was the only one to indicate short term water deficit after a rainfall. Hence, ΨT appears to be a useful indicator for grapevine management in both non-irrigated and irrigated vineyards.</p>

The leaf miner Phyllocnistis populiella negatively impacts water relations in aspen

2019 ◽  
Vol 40 (5) ◽  
pp. 580-590 ◽  
Author(s):  
Diane Wagner ◽  
Jenifer M Wheeler ◽  
Stephen J Burr
Keyword(s):  
Water Vapor ◽  
Water Potential ◽  
Water Content ◽  
Water Relations ◽  
Leaf Water Potential ◽  
Water Loss ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Leaf Miner ◽  
Phyllocnistis Populiella

Abstract Within the North American boreal forest, a widespread outbreak of the epidermal leaf miner Phyllocnistis populiella Cham. has damaged quaking aspen (Populus tremuloides Michx.) for nearly 20 years. In a series of experiments, we tested the effects of feeding damage by P. populiella on leaf water relations and gas exchange. Relative to insecticide-treated trees, the leaves of naturally mined trees had lower photosynthesis, stomatal conductance to water vapor, transpiration, water-use efficiency, predawn water potential and water content, as well as more enriched foliar δ13C. The magnitude of the difference between naturally mined and insecticide-treated trees did not change significantly throughout the growing season, suggesting that the effect is not caused by accumulation of incidental damage to mined portions of the epidermis over time. The contributions of mining-related stomatal malfunction and cuticular transpiration to these overall effects were investigated by restricting mining damage to stomatous abaxial and astomatous adaxial leaf surfaces. Mining of the abaxial epidermis decreased photosynthesis and enriched leaf δ13C, while increasing leaf water potential and water content relative to unmined leaves, effects consistent with stomatal closure due to disfunction of mined guard cells. Mining of the adaxial epidermis also reduced photosynthesis but had different effects on water relations, reducing midday leaf water potential and water content relative to unmined leaves, and did not affect δ13C. In the laboratory, extent of mining damage to the adaxial surface was positively related to the rate of water loss by leaves treated to prevent water loss through stomata. We conclude that overall, despite water savings due to closure of mined stomata, natural levels of damage by P. populiella negatively impact water relations due to increased cuticular permeability to water vapor across the mined portions of the epidermis. Leaf mining by P. populiella could exacerbate the negative effects of climate warming and water deficit in interior Alaska.

Effect of Water Deficit on Carbon Dioxide Exchange and Leaf Elongation Rate of Panicum maximum Var. trichoglume

1976 ◽  
Vol 3 (3) ◽  
pp. 401 ◽  
Author(s):  
MM Ludlow ◽  
TT Ng
Keyword(s):  
Carbon Dioxide ◽  
Water Potential ◽  
Leaf Water Potential ◽  
Net Photosynthesis ◽  
Stomatal Resistance ◽  
Leaf Water ◽  
Carbon Dioxide Exchange ◽  
Leaf Elongation ◽  
Water Deficits ◽  
Water Potentials

The responses of carbon dioxide exchange and leaf elongation of potted P. maximum var. trichoglume plants to water deficits were investigated in controlled environments and outdoors during drying cycles down to -92 bars leaf water potential, The sensitivities of net photosynthesis and leaf elongation to water deficits were similar. The leaf water potentials at which net photosynthesis and elongation ceased (c. -12 bars), and stomatal resistance increased substantially (- 6 bars), were relatively unaffected by nitrogen supply, environmental conditions during growth, and whether plants had previously experienced stress. However, these factors influenced the rate of net photosynthesis, at high leaf water potentials by affecting stomatal resistance and at moderate water potentials by affecting both stomatal and intracellular resistances. Stomata1 resistance was more sensitive than intracellular resistance to water deficits. Dark respiration rate decreased with leaf water potential, and was higher in plants receiving additional nitrogen. At moderate leaf water potentials (-7 to -9 bars), net photosynthesis of this C4 grass exhibited light saturation and rates similar to C3 plants. We suggest that the difference in behaviour of controlled-environment-grown and field-grown plants to water deficits observed with some species is unlikely to be due to differences in the aerial environment, but may result from differences in the rate at which stress develops. The ecological significance and evolution of the C4 syndrome are discussed briefly.

Water Relations in Cowpea and Pearl Millet Under Soil Water Deficits. III. Extent of Predawn Equilibrium in Leaf Water Potential

1992 ◽  
Vol 19 (6) ◽  
pp. 601 ◽  
Author(s):  
CL Petrie ◽  
AE Hall
Keyword(s):  
Water Potential ◽  
Pearl Millet ◽  
Leaf Water Potential ◽  
Leaf Surface ◽  
Leaf Water ◽  
Soil Drying ◽  
Mannitol Solution ◽  
Water Potentials ◽  
Approximate Equilibrium ◽  
Significant Difference

Pearl millet [Penniseturn americanum (L.) Leeke] consistently develops lower predawn leaf water potentials than cowpea [Vigna unguiculata (L.) Walp.] when plants are subjected to progressive soil drying, even when they are grown as intercrops in the same pot. Lack of equilibrium in water potential during the predawn, within the plants and between plants and soil, was studied as a possible explanation for this difference. Experiments were conducted in a glasshouse in pots containing an artificial rooting medium which had a high water-holding capacity and was easy to separate from roots. Leaf and root predawn xylem water potentials were measured with a pressure chamber. In cowpea, leaf water potential (ΨL) values during the dry treatment were similar to values of root water potential (ΨR), indicating an approximate equilibrium within the plants. In millet, measurements were made on plants grown in both large and small pots. With large pots, ΨL and ΨR values in millet were similar, but with small pots, predawn ΨL was lower than ΨR. When the surfaces of these small pots were covered with evaporation barriers, however, no significant differences developed between ΨL and ΨR at predawn during soil drying, indicating an approximate equilibrium within millet. During the early stages of the dry treatment, leaf surface conductances measured at predawn indicated that significant water flux occurred at night from the leaves of both cowpea and millet. Leaf surface conductances declined to negligible levels as the dry treatment progressed, however, and night-time fluxes of water from leaves cannot explain the significant difference in predawn ΨL that developed between cowpea and millet. In order to determine whether the lower predawn ΨL in millet was due to a resistance to water uptake at the root surface, an osmoticum (- 0.5 MPa mannitol solution) was applied to pots of cowpea and millet intercrops after substantial differences in predawn ΨL had developed, and ΨL was measured. Measurements taken 9 h later indicated that predawn ΨL had recovered in millet, and the values of ΨL in millet and cowpea after mannitol treatment were similar to the osmotic potential of the mannitol solution. These results suggest that the lower predawn ΨL in millet than in cowpea under drought is due to the development of a substantial soil resistance to water movement to the root surfaces of millet.

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