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.

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 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.

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.

scholarly journals Indicators of the water regime of some varieties of chrysanthemums in the conditions of the South Ural

2021 ◽  
Vol 10 (1) ◽  
pp. 57-64
Author(s):  
Svetlana Galimullovna Denisova ◽  
Antonina Anatolyevna Reut
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Water Regime ◽  
Water Holding Capacity ◽  
Research Centre ◽  
Total Water Content ◽  
Total Water ◽  
The South ◽  
Irreversible Damage ◽  
Water Holding

In introduction studies, it is of great importance to determine how favorable the water balance of the studied species is under given environmental conditions. The aim of the research was to study the water regime of some varieties of chrysanthemums in the conditions of the Southern Ural. The study was conducted in 20182020 on the basis of the South-Ural Botanical Garden-Institute of the Ufa Federal Research Centre of Russian Academy of Sciences. The objects of the study were 23 varieties of Chrysanthemum hortorum Bailey. In the course of the research, the total water content, water-holding capacity, the content of mobile moisture, water deficit, and sublethal water deficit were determined. The analysis of water regime indicators is based on the method of artificial wilting (V.N. Tarenkov, L.N. Ivanova) and the method of saturation of plant samples (V.P. Moiseev, N.P. Reshetsky). Sublethal water deficit was determined by the method of T.K. Goryshina, L.I. Samsonova, modified by N.I. Bobrovskaya. The calculations were carried out by standard methods using statistical packages of the Microsoft Excel 2003 and the Agros 2.13 program. The studies made it possible to determine the value of the sublethal water deficit (28,4%) for the varieties of chrysanthemums in the conditions of the Bashkir Ural. It was found that the studied varieties during the growing season did not experience such a moisture deficit in the tissues that could lead to irreversible damage to the assimilating organs. Our experiments showed that chrysanthemum varieties in the Bashkir Cis-Ural under the same soil-climatic and agrotechnical conditions had the following range of indicators of total water content 70,090,4% and water-holding capacity 19,0064,6%. The analysis of variance revealed significant differences between water-holding capacity and the content of mobile moisture by varieties, the share of influence was 27,8531,71%. As a result of the correlation-regression analysis, the authors revealed a direct dependence of the indicators of mobile moisture content on the total water content, and an inverse one on the indicators of the content of mobile moisture and water-holding capacity.

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