Root morphology and its contribution to a large root system for phosphorus uptake by Rytidosperma species (wallaby grass)

• Published in: Plant and soil Vol. 412; no. 1/2; pp. 7 - 19
• Main Authors: Waddell, Heidi A., Simpson, Richard J., Ryan, Megan H., Lambers, Hans, Garden, Denys L., Richardson, Alan E.
• Format: Journal Article
• Language: English
• Published: Cham Springer 01.03.2017; Springer International Publishing; Springer Nature B.V
• Subjects: Bioaccumulation; Biomedical and Life Sciences; Botanical research; Bromus hordeaceus; Ecology; Environmental aspects; Grasses; greenhouses; Indigenous species; Life Sciences; Lolium perenne; Phosphorus; Phosphorus (Chemical element); Physiological aspects; Plant growth; Plant morphology; Plant Physiology; Plant Sciences; Regular Article; root hairs; root systems; Roots; Roots (Botany); soil; Soil Science & Conservation; Studies; Australia; Root hairs; Root length; Root mass
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-016-2933-y

Aims: Rytidosperma species are native Australian grasses which have different growth rates and phosphorus (P) requirements. This study examined the role of root morphology traits in response to P supply. Methods: Nine Rytidosperma species ranging from slowto fast-growth were examined along with Lolium perenne and Bromus hordeaceus. Plants were grown in a glasshouse for 47 days in soil supplied with six levels of P between 0 and 60 mg P per pot. Root mass, length and diameter, root hair length and density, and extent of mycorrhizal colonisation were measured. Results: Across all species there was a positive correlation (P < 0.001) between P uptake and root mass, length and root hair cylinder volume (RHCV; estimated using root diameter, root hair length and root length) at all levels of P supply. An exception was the RHCV of B. hordeaceus, where expected P uptake was not achieved due to a markedly reduced root length at low-P supply. For the Rytidosperma species, morphological plasticity for specific root length, root mass fraction and root hair length ranged from 1.5-fold to 2.7-fold between high-and low-P supply. However, across all species and P levels no single root morphological trait was identified for universally increasing the size of the root system and P uptake. Conclusions: Fast-growing species took up more P as a result of an overall larger root mass, greater root length and larger RHCV.