Measurement of porosity in very small samples of plant tissue

• Published in: Plant and soil Vol. 253; no. 1; pp. 81 - 90
• Main Authors: Visser, Eric J.W., Bögemann, Gerard M.
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01.06.2003; Springer Nature B.V
• Subjects: Adventitious roots; Body tissues; Buoyancy; Floods; Microbalances; Plant roots; Plant species; Plant tissues; Plants; Porosity; Root tips; Roots; Salinity tolerance; Tissue samples; Waterlogging
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1023/a:1024560322835

The relative volume of internal gas spaces (i.e., porosity) of the shoot and roots of a plant largely determines its resistance to flooding, as oxygen may diffuse through these cavities from non-flooded parts of the plant into the submerged tissues. The current techniques to measure porosity either need relatively large amounts of plant tissue (200 mg per sample), or are time-consuming and not sufficiently accurate for specific types of plant material. These limitations were the reason to develop a new method of porosity measurement. Small segments of roots were taken from freshly harvested plants, placed in a two-piece hard gelatin capsule and weighed on a microbalance. The root segments were subsequently infiltrated with water under vacuum, blotted carefully and weighed again. Using the increase in weight and the specific weight of infiltrated tissue, derived from a larger sample of roots, it was possible to calculate the porosity of individual root segments as small as 3–5 mg with a length of 5 mm. The new method combines this use of small samples with a high accuracy, and proved useful for a variety of plant species. Porosity data obtained with this method will improve our knowledge of small-scale processes such as aerenchyma development in root tips.