Table 3.
Data providing estimates of cytoplasmic ion concentrations in cells of halophytes and in a salt-adapted cell culture of tobacco
| Species | Tissue | External NaCl (mm) | Estimated cytoplasmic ion concentration (mm) |
Na/K ratio | Original units | Method of analysis | Comment | Reference | ||
|---|---|---|---|---|---|---|---|---|---|---|
| Na | K | Cl | ||||||||
| Suaeda maritima | Mature leaf mesophyll cytoplasm-cell wall | 340 | 101–209 | 0–40 | 30–191 | 5·2–8·8 | mol m–3 analysed volume | X-ray microanalysis using transmission microscopy following freeze-substitution; cytosol | Calibrated X-ray microscopy. The values are calculated from mol m–3 analysed volume assuming a water content of 70 %. The area analysed included some cell wall. | Harvey et al. (1981) |
| Suaeda maritima | Leaf cells | 340 | 165 | – | – | – | Counts per unit tissue | Flux analysis using 22Na | Cell and cytoplasmic volumes estimated from electron micrographs. | Yeo (1981) |
| Zostera marina | Leaf mesophyll | Sea water | ND | ND | ND | 0·11 | Counts s–1 | X-ray microanalysis after freeze drying and dry sectioning | Data not calibrated, but vacuolar counts for Na in the leaf mesophyll were 4·7 times those in the cytoplasm. Leaf Na+ concentrations ranged from 245 to 317 mm based on plant water concentration. | Ye and Zhao (2003) |
| Atriplex spongiosa | Mature leaf | 600 | See comments | – | 0·29 | Counts s–1 | X-ray microanalysis of frozen hydrated specimens using scanning microscopy | The authors calculated Na + K to be 107 mm, a much lower value than the tissue concentration of about 800 mm (270 mm Na+ + 128 mm K+). | Storey et al. (1983a) | |
| Atriplex spongiosa | Bundle sheath mature leaf | 200 | See comments | 0·53 | Counts s–1 | Cells with little vacuolation X-ray microanalysis of frozen hydrated specimens using scanning microscopy | The authors calculated (K + Na) in the cytoplasm to be 30, 20 and 14 % of that in the vacuole in 200, 400 and 200 mm NaCl, respectively. | Storey et al. (1983a) | ||
| 400 | 0·44 | |||||||||
| 600 | 0·47 | |||||||||
| Suaeda maritima | Root mature cortical cells 10–20 mm behind tip | 200 | 168 | 78 | 128 | 2·1 | mol m–3 analysed volume | X-ray microanalysis using transmission microscopy following freeze-substitution | The tabulated values are calculated from mol m–3 analysed volume assuming a water content of 70 %. Standards were used for calibration. | Hajibagheri and Flowers (1989) |
| Suaeda maritima | Root cells | 340 | 150 | – | – | – | Counts per unit tissue | Flux analysis using 22Na | Cell and cytoplasmic volumes estimated from electron micrographs. | Yeo (1981) |
| Atriplex spongiosa | Root meristematic cells | 200 | 0·20 | Counts s–1 | Cells with little vacuolation. X-ray microanalysis of frozen hydrated specimens using scanning microscopy | Calculated from counts using a value of 8·2 μmol g–1 water). Na/K ratios are for counts data. Uncalibrated X-ray data. | Storey et al. (1983b) | |||
| 400 | 0·38 | |||||||||
| 600 | 80 | 120 | 70 | 0·79 | ||||||
| Suaeda maritima | Root tip 60-day-old plants | 340 | 105 | 227 | – | 0·49 | mol m–3 tissue volume | Cells with little vacuolation. Atomic absorption spectroscopy | Concentrations are for apical mm as quoted in table 4 of the paper. | Hajibagheri et al. (1985) |
| Atriplex amnicola | Root tip (12 mm) | 200 | 66 | 225 | – | 0·27 | mm | Cells with little vacuolation. Atomic absorption spectroscopy and coulometric titration | Based on protoplast water for apical 12 mm sections of roots. | Jeschke et al. (1986) |
| 400 | 161 | 225 | 181 | 0·72 | ||||||
| Atriplex nummularia | Roots | 50 | 198 | 143 | – | 1·4 | Counts per unit tissue | Flux analysis using 22Na and 86Rb | Using sections, to estimate volumes; cytoplasmic volume of 5 %. | Mills et al. (1985) |
| Triglochin maritimum | Root cells | 100 | 104 | – | Counts per unit tissue | Flux analysis using 24Na or 42K as NaCl and KCl | Cell sizes estimated from sections and light microscopy. | Jefferies (1973) | ||
| 500 | 71 | 2·1 | ||||||||
| (8 K+) | 148 | |||||||||
| Eleocharis uniglumis | Root cells | 74 | 192 | – | – | Counts / unit tissue | Flux analysis using 22Na | The concentration was estimated by dividing the quantity in the compartment by its estimated volume determined from sections. | Shepherd and Bowling (1979) | |
| Puccinellia peisonis | Root rhizodermis | 40 | 70 | 2 | – | 0·02 | Counts | X-ray microanalysis of frozen hydrated specimens using scanning microscopy | Used aqueous standards containing BSA that slightly underestimated concentrations. | Koyro and Stelzer (1988) |
| Spartina townsendii | Root rhizodermis | 40 | 5 | 32 | – | 0·16 | Counts | X-ray microanalysis of frozen hydrated specimens using scanning microscopy | Used aqueous standards containing BSA that slightly underestimated concentrations. | Koyro and Stelzer (1988) |
| Nicotiana tabaccum cell culture | Adapted cells in early stationary phase | 428 | 96 | – | 96 | – | Counts (plus morphometry and whole cell concentration data) | Cells with little vacuolation. X-ray microanalysis | Cytoplasm was 45 % of cell volume. Vacuolar concentration was 780 mm Na+ and 624 mm Cl–. | Binzel et al. (1988) |
BSA, bovine serum albumin; ND, not determined.