Key points are not available for this paper at this time.
Soil compaction often imposes stress on root development and plant survival. However, root anatomical responses that enable persistent root growth and functioning under soil compaction remain unclear. We grew 10 herbaceous species differing substantially in lateral root diameter, in soils with low (1.0 g cm −3 ) and high (1.4 g cm −3 ) bulk density, and assessed root traits including root biomass, anatomical structures, and respiration rates. Greater root thickening upon soil compaction was found in species with thicker first-order lateral roots, mainly due to larger cortical cell size. Both xylem vessel diameter and wall thickness increased more in compacted soils in these species. Despite these anatomical shifts, root respiration rate responded little to soil compaction across most species, likely due to the opposite investment in cortical cells and xylem vessels. Notably, root biomass, independent of root respiration rate and anatomical structures, determined whole-plant growth under soil compaction. Our study reveals two independent strategies of root response to soil compaction: anatomical remodeling for mechanical and metabolic maintenance, and root biomass investment for resource acquisition. These findings offer new insights for breeding and selecting species tolerant to soil compaction and highlight multidimensional strategies of plant adaptation to physical stress. • Species with thicker lateral roots exhibit greater root diameter increase in compacted soil due to larger cortical cell size. • Most species’ root respiration rate remains constant in compacted soil due to opposing investment in the cortex and vessels. • Root biomass, independent of root anatomical responses to soil compaction, determines whole-plant growth in compacted soil.
Han et al. (Thu,) studied this question.