A Special Role of the Rhizodermis in Nutrient Uptake by Plant Roots
Abstract
Summary. Using the possibility of selective killing the rhizodermis by means of osmotic shock further evidence is produced for the hypothesis of a restricted diffusion into the free space of a higher plants root cortex and of a special role of the rhizodermis in uptake processes of plant roots.
Osmotic shock causes a strong decrease of phosphate uptake from low-concentrated solutions due to an osmotic rupture of rhizodermal cells. Phosphate uptake from higher concentrated solutions is only slightly influenced. It is concluded that phosphate uptake from low-concentrated solutions takes place at the shock-sensitive tissue surface only whereas higher concentrations permit the diffusion of the solute into the free space and, therefore, allow the shock-insensitive cortical cells to take part in the uptake process. This view is supported by a second line of evidence coming from the investigation of the time course and the temperature dependence of phosphate uptake and from measurements of the trans-membrane potential difference.- Publication:
-
Biochemie und Physiologie der Pflanzen
- Pub Date:
- 1979
- DOI:
- 10.1016/S0015-3796(17)30649-2
- Bibcode:
- 1979BioPP.174..831G
- Keywords:
-
- osmotic shock;
- rhizodermis;
- phosphate uptake;
- uptake isotherms;
- Zea mays