A simple pressure-probe method for the determination of volume in higher-plant cells

Planta ◽  
1990 ◽  
Vol 182 (2) ◽  
Author(s):  
M. Malone ◽  
A.D. Tomos
Keyword(s):  
Plant Cells ◽  
Probe Method ◽  
Pressure Probe ◽  
Higher Plant

Comparison Between Osmotic and Hydrostatic Water Flows in a Higher Plant Cell: Determination of Hydraulic Conductivities and Reflection Coefficients in Isolated Epidermis of Tradescantia virginiana

1982 ◽  
Vol 9 (4) ◽  
pp. 461 ◽  
Author(s):  
SD Tyerman ◽  
E Steudle
Keyword(s):  
Osmotic Pressure ◽  
Turgor Pressure ◽  
Water Volume ◽  
Pressure Probe ◽  
Reflection Coefficients ◽  
Higher Plant ◽  
Bathing Medium ◽  
Tradescantia Virginiana ◽  
Cell Turgor

Hydraulic conductivity (Lp), volumetric elastic modulus (ε) and reflection coefficients (δ) have been determined for cells from isolated strips of the lower epidermis of leaves of Tradescantia virginiana using the pressure probe. Lp was (6.4 � 4.5) × 10-8 ms-1 Mpa-1 [(6.4 � 4.5) × 10-7 cm s-1 bar-1; mean � s.d., n = 15 cells] and was independent of the cell turgor pressure (P) and of osmotic pressure of the bathing medium. P in Johnson's solution (π° = 0.09 MPa) was 0.42-0.67 MPa (4.2-6.7 bar), which was somewhat larger than in the intact tissue. ε increased linearly with increasing P in the pressure range from zero to full turgor. Reflection coefficients of some non-electrolytes were determined by measuring the ΔP in response to a change in external osmotic pressure (Δπ°) after the addition of the solutes. The data were corrected for solute flow. For sucrose, mannitol, urea, acetamide, formamide, glycerol and ethylene glycol, δ was close to unity and the cells behaved like ideal osmometers. For the monohydroxyalcohols n-propanol ( δ = -0.58), isopropanol (δ = 0.26), ethanol (δ = 0.25) and methanol (δ = 0.15), rather low reflection coefficients were found which were even negative for some solutes and cells. Values of δ obtained from measuring the inital water (volume) flow were in agreement with those determined from the ΔP/Δπ° ratios. For the rapidly permeating substances, the changes in turgor after the addition of solute were transient and the equilibration of solutes between cell and medium could be measured using the probe. Although unstirred layers may affect the equilibration of solute it should, in principle, be possible to use the technique for the determination of permeability coefficients of membranes of higher plant cells.

Mass-spectrometric determination of O2 and CO2 gas exchange in illuminated higher-plant cells

Planta ◽  
1991 ◽  
Vol 183 (2) ◽  
Author(s):  
Marie-H�l�ne Avelange ◽  
JeanM. Thi�ry ◽  
Fr�d�ric Sarrey ◽  
Pierre Gans ◽  
Fabrice R�beill�
Keyword(s):  
Gas Exchange ◽  
Plant Cells ◽  
Mass Spectrometric ◽  
Higher Plant ◽  
Co2 Gas ◽  
Co2 Gas Exchange ◽  
Mass Spectrometric Determination

Inhibition of carbon fixation as a function of zinc uptake in natural phytoplankton assemblages

1979 ◽  
Vol 59 (4) ◽  
pp. 937-949 ◽  
Author(s):  
Anthony G. Davies ◽  
Jillian A. Sleep
Keyword(s):  
Carbon Fixation ◽  
Natural Populations ◽  
Plant Cells ◽  
Toxic Metal ◽  
Vitamin B ◽  
Phytoplankton Assemblages ◽  
Metal Contents ◽  
Rate Limiting ◽  
Natural Phytoplankton

There is now a substantial body of evidence that the growth rates of phytoplankton in culture are more closely related to the cellular levels of the rate-limiting constituent, be it a nutrient, micronutrient or toxic metal, than to the concentrations in the supporting medium; nitrate, Caperon (1968); phosphate, Fuhs (1969); silicate, Paasche (1973); vitamin B12, Droop (1968); iron, Davies (1970); mercury, Davies (1974); cadmium, Davies (1978a). This has suggested the requirement for a technique which would allow the determination of comparable relationships for natural populations of phytoplankton - how, for instance, their carbon fixation rates depend upon the metal contents of the plant cells. Although the effects of metals upon carbon fixation in phytoplankton assemblages from several different sea areas have already been examined (Knauer & Martin, 1972; Patin et al. 1974; Zingmark & Miller, 1975; Ibragim & Patin, 1976) no data seem to have been obtained on the levels of the metals present in the phytoplankton at the time of the measurements.

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