The characteristics of seasonal and ontogenetic changes in the tissue – water relations of Acer, Populus, Tsuga, and Picea

1978 ◽  
Vol 56 (6) ◽  
pp. 635-647 ◽  
Author(s):  
M. T. Tyree ◽  
Y. N. S. Cheung ◽  
M. E. MacGregor ◽  
A. J. B. Talbot
Keyword(s):  
Osmotic Pressure ◽  
Water Relations ◽  
Acer Saccharum ◽  
Tsuga Canadensis ◽  
Annual Maximum ◽  
Ontogenetic Changes ◽  
Tissue Water ◽  
Maximum Value ◽  
Pressure Bomb ◽  
Bulk Elastic Modulus

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.

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
Keyword(s):  
Cell Wall ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Turgor Pressure ◽  
Systematic Errors ◽  
Tissue Water ◽  
Cell Wall Elasticity ◽  
Pressure Bomb ◽  
Bomb Method

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).

The water relations of hemlock (Tsuga canadensis). IV. The dependence of the balance pressure on temperature as measured by the pressure-bomb technique

1974 ◽  
Vol 52 (5) ◽  
pp. 973-978 ◽  
Author(s):  
M. T. Tyree ◽  
J. Dainty ◽  
D. M. Hunter
Keyword(s):  
Temperature Dependence ◽  
Water Potential ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Turgor Pressure ◽  
Tsuga Canadensis ◽  
Constant Volume ◽  
Pressure Bomb

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.

The water relations of hemlock (Tsuga canadensis). I. Some equilibrium water relations as measured by the pressure-bomb technique

1973 ◽  
Vol 51 (8) ◽  
pp. 1471-1480 ◽  
Author(s):  
M. T. Tyree ◽  
J. Dainty ◽  
M. Benis
Keyword(s):  
Water Content ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Tsuga Canadensis ◽  
Living Cells ◽  
Total Water Content ◽  
Total Water ◽  
Fresh Weight ◽  
Volume Changes ◽  
Pressure Bomb

Theoretical and experimental aspects of the equilibrium water relations of excised hemlock (Tsuga canadensis) shoots are examined. The equilibrium water relations of hemlock were determined by using the pressure-bomb technique on shoots 15 to 40 g in fresh weight. At or near full turgor the osmotic pressure of the cells averages 16.5 + 0.4 bars. The fraction of the total water content of hemlock shoots residing in the living cells is 0.77 + 0.04. When hemlock shoots are near full turgor the balancing pressure will change linearly with the volume expressed provided the volume changes represent less than [Formula: see text] of the total shoot water content.

Relative Drought Resistance of Tristaniopsis laurina and Acmena smithii From Riparian Warm Temperate Rainforest in Victoria

1990 ◽  
Vol 38 (4) ◽  
pp. 361 ◽  
Author(s):  
DR Melick
Keyword(s):  
Drought Tolerance ◽  
Water Relations ◽  
Drought Resistance ◽  
Leaf Abscission ◽  
Tissue Water ◽  
Temperate Rainforest ◽  
Direct Observations ◽  
Pressure Bomb ◽  
Warm Temperate ◽  
Adult Plants

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.

Facing drought in a Mediterranean post-fire community: tissue water relations in species with different life traits

2004 ◽  
Vol 25 (1-2) ◽  
pp. 67-72 ◽  
Author(s):  
Marco Borghetti ◽  
F. Magnani ◽  
A. Fabrizio ◽  
A. Saracino
Keyword(s):  
Water Relations ◽  
Tissue Water ◽  
Life Traits

WATER RELATIONS OF ASEXUAL SPORES OF SPHAEROTHECA MACULARIS (WALLR. EX. FR.) COOKE AND ERYSIPHE POLYGONI DC.

1965 ◽  
Vol 11 (3) ◽  
pp. 531-538 ◽  
Author(s):  
J. S. Jhooty ◽  
W. E. McKeen
Keyword(s):  
Relative Humidity ◽  
Water Content ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Erysiphe Polygoni ◽  
Significant Change ◽  
Sphaerotheca Macularis ◽  
Glass Surfaces

The conidia of Sphaerotheca macularis germinate best at a relative humidity (R.H.) of 99 and 100% on glass surfaces, and germination does not occur if the R.H. is below 93%. Conidia of Erysiphe polygoni DC. germinate at 3% R.H. The water content of conidia of S. macularis and E. polygoni is 53 and 69% respectively. The osmotic pressure of S. macularis conidia is about 18 atm and their density varies from 1.10 to 1.11 g/ml. There is no significant change in the diameter and length of the conidia during germination.

Water Relations in Young Growing Wheat Leaves after Application of (2-Chloroethyl)trimethyl- ammoniumchloride (CCC) to the Roots of Wheat Seedlings

1985 ◽  
Vol 40 (9-10) ◽  
pp. 745-747
Author(s):  
Jutta Bode ◽  
Aloysius Wild
Keyword(s):  
Water Relations ◽  
Reducing Sugars ◽  
Triticum Aestivum L ◽  
Water Deficiency ◽  
Pressure Potential ◽  
Tissue Water ◽  
Wheat Seedlings ◽  
Diffusive Resistance ◽  
Wheat Leaves ◽  
Synthetic Growth

Abstract The influence on the water relations of the third developing leaf of (2-chloroethyl)trimethylammoniumchloride, a synthetic growth regulator, applied to the roots of young wheat plants (Triticum aestivum L.) has been investigated. The tissue water potential and the pressure potential were found to be reduced by several bars in comparison to the untreated controls, whereas the osmotic potential remained unchanged. The content of soluble reducing sugars was considerably increased in the cell sap of CCC-treated leaves. With this accumulation, however, the turgor was not maintained. Additionally, CCC-treated leaves showed considerably lower transpiration rates and higher diffusive resistance than the controls. Thus, the application of CCC to the roots causes alterations in the water relations of developing wheat leaves, which resemble those induced by water deficiency.

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