Summary
Tomato plants were treated for one hour in nutrient solutions at-10.4 atm. Roots were excised, transferred to solutions at-0.4 atm and put into a pressure chamber to induce rates of water flow similar to those in transpiring plants.
For roots continuously at-0.4 atm, the xylem sap had much higher phosphorus concentrations than the external solution, which contained 6 p.p.m. phosphorus.
Roots previously treated at-10.4 atm had much lower concentrations in the sylem sap than in the external solution and the amount of phosphorus transported and the water flow were linearly related. This phosphorus transport was due to passive movement as shown by measuring transport of both 32P and 14C mannitol. Thus transport to the xylem mediated by active processes was abolished even though uptake by the roots remained substantial. These results obtained after plasmolysis support the view that radial transport to the xylem includes uptake into and movement through the symplast.
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References
Greenway, H.: Plant responses to saline substrates. IV. Chloride uptake by Hordeum vulgare as affected by inhibitors, transpiration, and nutrients in the medium. Aust. J. biol. Sci. 18, 249–268 (1965).
—: Effects of exudation on ion relationships of excised roots. Physiol. Plantarum (Copenh.) 20, 903–910 (1967).
Greenway, H., P. G. Hughes, and Betty Klepper: Effects of water stress on phosphorus nutrition of tomato plants. J. exp. Bot., submitted for review.
—, Betty Klepper, and P. G. Hughes: Effects of low water potential on ion uptake and loss for excised roots. Planta (Berl.) 80, 129–141 (1968).
Ingelsten, B.: Absorption and transport of sulfate by wheat at varying mannitol concentration-in the medium. Physiol. Plantarum (Copenh.) 19, 563–579 (1966).
Jackson, J. E., and P. E. Weatherley: The effect of hydrostatic pressure gradients on the movement of sodium and calcium across the root cortex. J. exp. Bot. 13, 403–413 (1962).
Linser, H., H. H. Mayr u. C. Chwala: Der Einfluß des osmotischen Drucks einer Nährlösung auf die Phosphoraufnahme durch Wurzeln von Lycopersicon esculentum. Atompraxis 8, 4–6 (1962).
Torii, K., and G. G. Latles: Dual mechanism of ion uptake in relation to vacuolation of corn roots. Plant Physiol. 41, 863–870 (1966).
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Klepper, B., Greenway, H. Effects of water stress on phosphorus transport to the xylem. Planta 80, 142–146 (1968). https://doi.org/10.1007/BF00385589
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DOI: https://doi.org/10.1007/BF00385589