Measurement of fine root tissue density: a comparison of three methods reveals the potential of root dry matter content

• Published in: Plant and soil 2014-01, Vol.374 (1/2), p.299-313
• Main Authors: Birouste, Marine, Zamora-Ledezma, Ezequiel, Bossard, Carine, Pérez-Ramos, Ignacio M., Roumet, Catherine
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Animal, plant and microbial ecology; Average linear density; Biological and medical sciences; Biomedical and Life Sciences; Cell growth; Datasets; Density; Dry matter; Ecology; Fundamental and applied biological sciences. Psychology; General agronomy. Plant production; Image analysis; Imaging systems; Life Sciences; Methods; Physiological aspects; Plant biology; Plant ecology; Plant growth; Plant Physiology; Plant roots; Plant Sciences; Plant species; Plant tissues; Plants; Rangeland soils; Regular Article; Roots (Botany); Soil ecology; Soil Science & Conservation; Soil-plant relationships. Soil fertility; Soil-plant relationships. Soil fertility. Fertilization. Amendments; Species; Studies
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-013-1874-y

Aims Root tissue density (RTD, the ratio of root dry mass to root volume) is a fundamental trait in comparative root ecology, being increasingly used as an indicator of plant species' resource use strategy. However, the lack of standardized method to measure this trait makes comparisons tricky. This study aims to compare three methods commonly used for determining fine RTD and to test whether root dry matter content (RDMC, the ratio between root dry mass and root fresh mass) could be used as a surrogate of fine root tissue density. Methods RTD of 163 fine root samples was determined using (i) Archimedes' method, (ii) image analysis (WinRHIZO software), and (iii) using the root dry matter content as a proxy. Root samples belonged to different herbaceous species grown in different conditions. Results RTD measured with Archimedes' method was positively correlated with RTD estimated with image analysis and with RDMC. However we demonstrated that RTD measured with Archimedes' method was better predicted by RDMC (R²=0.90) than by RTD measured with image analysis (R²=0.56). The performance and limitations of each method were discussed. Conclusion RDMC is a quick, cheap and relatively easy measurable root attribute; we thus recommended its measurement as a proxy of fine root tissue density.