Plant density modifies root system architecture in spring barley (Hordeum vulgare L.) through a change in nodal root number

• Published in: Plant and soil Vol. 439; no. 1/2; pp. 179 - 200
• Main Authors: Hecht, V. L., Temperton, V. M., Nagel, K. A., Rascher, U., Pude, R., Postma, Johannes A.
• Format: Journal Article
• Language: English
• Published: Cham Springer Science + Business Media 01.06.2019; Springer International Publishing; Springer; Springer Nature B.V
• Subjects: Architecture; Barley; Biomedical and Life Sciences; branching; Cultivars; Ecology; field experimentation; fine roots; Growth rate; Hordeum vulgare; ideotypes; Life Sciences; plant density; Plant growth; Plant Physiology; Plant Sciences; Planting density; REGULAR ARTICLE; root crown; root growth; root systems; Roots; Soil Science & Conservation; sowing; spring barley; Topsoil; Germany; Tiller counts; Plant competition; Branching angle; Lab to field; Nodal & seminal roots; Lateral branching frequency
• ISSN: 0032-079X; 1573-5036
• DOI: 10.1007/s11104-018-3764-9

Aim Previously, we showed that sowing density influences root length density (RLD), specific root length (SRL) especially in the topsoil, and shallowness of fine roots of field grown spring barley ( Hordeum vulagre L.). Here, we ask which trait components may explain these observed changes. Method We grew two spring barley cultivars at contrasting sowing densities in both field trials and rhizotrons, and excavated root crowns and imaged root growth. Results In the field, tiller and nodal root numbers per plant decreased with increasing sowing density, however, nodal roots per tiller, seminal roots per plant, and lateral branching frequencies were not affected. Branching angle did not or only slightly declined with increasing sowing density. In rhizotrons, aboveground only tiller number was affected by sowing density. Root growth rates and counts were not (or only slightly) affected. Conclusion Greater RLD at high sowing densities is largely explained by greater main root number per area. The altered seminal to nodal root ratio might explain observed increases in SRL. We conclude that sowing density is a modifier of root system architecture with probable functional consequences, and thereby an important factor to be considered in root studies or the development of root ideotypes for agriculture.