Radial Turgor Pressure Profiles in Growing and Mature Zones of Wheat Roots—A Modification of the Pressure Probe

• Published in: Journal of experimental botany Vol. 40; no. 5; pp. 567 - 571
• Main Authors: PRITCHARD, J., WILLIAMS, G., JONES, R G. WYN, TOMOS, A. D.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-05-1989
• Subjects: Biological and medical sciences; Cell growth; Corn; Fundamental and applied biological sciences. Psychology; Plant growth; Plant growth. Development of the storage organs; Plant physiology; Plant physiology and development; Plant roots; Plant tissues; Pressure probe; Pressure sensors; Root cap; Root growth; salt solution; Turgor pressure; Vegetative apparatus, growth and morphogenesis. Senescence; wheat roots; Monocotyledones; Root; Turgor; Growth; Nutrient solution; Instrumentation; Ion distribution; Gramineae; Angiospermae; Spermatophyta; Measurement method; Osmotic pressure; Triticum aestivum
• ISSN: 0022-0957; 1460-2431
• DOI: 10.1093/jxb/40.5.567

A modification of the pressure probe is described which allows accurate routine recording of the turgor pressure of single cells at measured depth within a tissue. Measurements of radial profiles of turgor pressure in wheat roots grown in some simple salt solutions (0.5 mol m−3 CaCl2, 0.5 mol m−3 CaCI2 plus 10 mol m−3 NaCl, and 0.5 mol m−3 CaCl2 plus 10 mol m−3 KCI), are described. Turgor pressure was constant (approximately, 0.65 MPa) along a radius within the elongation zone irrespective of the nature of the bathing solution. In mature root tissue turgor pressure in the cortex was lower than that of the growing zone in all treatments and the pressure of the stele was on average 0.22 MPa higher than that of the cortex. Potassium in the medium bathing the root increased the turgor pressure in mature root (both cortex and stele) relative to low salt and sodium treatments. The results are discussed in relation to both root growth and ion accumulation.