A comparison of systematic errors between the Richards and Hammel methods of measuring tissue – water relations parameters

1978 ◽  
Vol 56 (17) ◽  
pp. 2153-2161 ◽  
Author(s):  
M. T. Tyree ◽  
M. E. MacGregor ◽  
A. Petrov ◽  
M. I. Upenieks

The pressure bomb is being used to a much greater extent to measure some tissue – water relations parameters such as osmotic pressure, turgor pressure, and cell wall elasticity. Recently, Richards has developed a faster pressure-bomb method of obtaining these and other parameters than the method used by Hammel and modified by us. In this paper, we compare the two methods and conclude that Richards’ method should not be used when accuracy is deemed important. The Richards method usually overestimates osmotic pressure by 0.2 MPa (= 2 bars) and sometimes by 0.8 MPa (= 8 bars).

1975 ◽  
Vol 53 (13) ◽  
pp. 1342-1346 ◽  
Author(s):  
Y. N. S. Cheung ◽  
M. T. Tyree ◽  
J. Dainty

The physical implications of the various parameters obtained from a pressure-bomb study are explored and related to their possible ecological significance. Our analysis suggests that the original bulk osmotic pressure, the bulk osmotic pressure at incipient plasmolysis, and cell wall elasticity are closely associated with the extent to which a leaf can osmoregulate or conserve water within a certain range of water potential change in the environment and might therefore have certain adaptive value. The pressure–volume relation could be applied to predict changes in leaf water potential at various degrees of water loss in the field. The values of these various parameters were obtained from a pressure-bomb study on single leaves from a wide variety of species. The use of data from single leaves as compared with whole shoots is discussed.


1974 ◽  
Vol 52 (5) ◽  
pp. 973-978 ◽  
Author(s):  
M. T. Tyree ◽  
J. Dainty ◽  
D. M. Hunter

The temperature dependence of the balance pressure is reported for shoots of Tsuga canadensis at constant volume, i.e., when water is neither added to nor removed from the shoot. Since the balance pressure closely equals minus the water potential, the temperature dependence of the balance pressure should reflect the combined temperature dependence of the osmotic and turgor pressures. Both the osmotic and the turgor pressures decline with decreasing temperature; frequently the turgor pressure declines 2 to 3 times more rapidly than the osmotic pressure, causing the balance pressure to rise with decreasing temperature. Only when the turgor pressure is zero (only beyond incipient plasmolysis) does the temperature dependence of the balance pressure closely follow the temperature dependence of the osmotic pressure; this occurs when the balance pressure equals or exceeds 24 bars.


1978 ◽  
Vol 56 (6) ◽  
pp. 635-647 ◽  
Author(s):  
M. T. Tyree ◽  
Y. N. S. Cheung ◽  
M. E. MacGregor ◽  
A. J. B. Talbot

The Scholander–Hammel pressure bomb has been used to measure ontogenetic and seasonal changes in π0 (the osmotic pressure of the symplasm at zero water potential), πp (the osmotic pressure of the symplasm at ‘incipient plasmolysis’), εmax (the bulk elastic modulus near maximum turgor), and a number of other water relations parameters in single leaves of Acer saccharum and several species of Populus and in shoots of Tsuga canadensis and Picea abies. In newly emerged leaves of Acer, Populus, and Picea, π0, πp, and εmax are all small but rise rapidly with leaf development. These parameters stabilize at a maximum value or slowly increase with progress in season. In Acer, εmax declines shortly before senescence. In developing leaves, the water content reaches a maximum before the soluble solutes; this accounts for the low values of π0 and πp.In Tsuga π0 cycles through an annual maximum in winter and a minimum in summer. These changes may correlate with frost hardiness.


1989 ◽  
Vol 16 (6) ◽  
pp. 517 ◽  
Author(s):  
SD Tyerman ◽  
P Oats ◽  
J Gibbs ◽  
M Dracup ◽  
H Greenway

Nicotiana tabacum plants were grown in solution culture with salinity treatments of 1, 100 and 200 mol m-3 [NaCl], in Hoagland solution. After several weeks, solute concentrations and osmotic pressure of cell sap from the roots were measured. Increases in cellular [Na+] and [Cl-] and a smaller reduction in [K+] accounted for the difference in sap osmotic pressure between the 200 mol m-3 and 1 mol m-3 treatments. Turgor pressure (P) of fully expanded cortex cells measured with the pressure probe were 0.48 MPa in 1 mol m-3, 0.24 MPa in 100 mol m-3, 0.20 MPa in 200 mol m-3, and these values agreed with those calculated by difference between internal and external osmotic pressure. Low values of volumetric elastic modulus (ε), ranging from 1.2 MPa to 3.0 MPa at P = 0.42 MPa were obtained, which accounted for long equilibration times to changes in water potential. There was no effect of high salinities on ε after accounting for the fact that ε was a function of P and neither was there an effect on hydraulic conductivity (Lp), which ranged between 1.9 × 10-8 and 24.1 × 10-8 m s-1 Mpa-1. At 200 mol m-3 [NaCl]o, and to a lesser degree at 100 mol m-3 [NaCl]o, root hairs became deformed to resemble spherical bladders (mean diameter = 88 �m) which displayed similar P and water relations to other epidermal cells and cortex cells. In other experiments the response to a sudden reduction in [NaCl], from 200 to 1 mol m-3 was studied. P of cortex cells first rapidly increased from about 0.15 MPa to 0.53 MPa and then slowly declined with a half time of about 35 min to a new steady state of 0.3 MPa. This level was maintained in intact roots for at least 48 h. The rate of the initial increase in P is limited by water flow into the cells while the slow decline is limited by solute efflux from the cells with water following osmotically. The efflux was mainly in response to reduced external osmotic pressure rather than [NaCl]o. Efflux of Na+, K+ and Cl- accounted for the decrease in internal osmotic pressure but it is possible that the membrane also became more permeable to sugars. With the exception of bladder hairs, the overall integrity of the cell membrane was maintained since Lp did not increase and P declined smoothly to the new level with no evidence of rupture and resealing of the membrane. It is argued that the loss of solutes after the step down in external osmotic pressure consists of turgor or volume regulation in which solute permeability increases steeply as turgor or volume goes above a threshold.


1984 ◽  
Vol 35 (6) ◽  
pp. 841-858 ◽  
Author(s):  
JOON HO KIM ◽  
OK YOUNG LEE-STADELMANN

1990 ◽  
Vol 38 (4) ◽  
pp. 361 ◽  
Author(s):  
DR Melick

The drought tolerances of the warm temperate rainforest species Tristaniopsis laurina and Acmena smithii were examined. Using pressure bomb techniques the tissue water relations of hardened juvenile and adult material were measured. T. laurina showed relatively little physiological drought tolerance in either the juvenile or adult plants, whereas A. smithii showed an increase in physiological drought tolerance in adult plants. Direct observations of droughted hardened 9-month-old seedlings revealed a relatively high leaf conductance in T. laurina seedlings with wilting becoming generalised after 9 days of droughting. All T. laurina plants rehydrated after 15 days of drought survived albeit with significant leaf abscission, but only 2 of the 5 plants rehydrated after 20 days of drought recovered and these were defoliated. Stomatal resistances were higher in droughted A. smithii seedlings and wilting did not become generalised until after 14 days of droughting. All A. smithii plants recovered when rehydrated after 20 days of droughting with little or no sign of leaf abscission. Leaves of T. laurina and A. smithii became scorched when subjected to temperatures of 50°C and 60°C respectively. The extent to which these differences delimit the distribution of these species in the relatively dry warm temperate rainforest communities of Gippsland in Victoria is discussed.


2019 ◽  
Vol 4 (2) ◽  
pp. 641-646 ◽  
Author(s):  
Jan T. Burri ◽  
Hannes Vogler ◽  
Gautam Munglani ◽  
Nino F. Laubli ◽  
Ueli Grossniklaus ◽  
...  

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