Effect of localized phosphorus supply on root morphological traits and their contribution to phosphorus uptake in wild soybean

A soil column experiment simulating the localized supplies of phosphorus (P) was conducted to quantitatively evaluate the effect of localized P supply on root morphological parameters and the contribution of root morphological parameters to P uptake in wild soybean (Glycine soja Sieb. et Zucc). The results showed that localized P supply significantly modified the root morphological parameters in wild soybean. Total root length, specific root length and root surface area increased by 80.5%, 32.6% and 70.7%, respectively, while average root diameter decreased by 27.6%. Adjustment of root morphology resulted in the 43.2% increase in shoot P uptake and 72.0% increase in aboveground dry weight, respectively. In all of the root morphological parameters, total root length, root surface and specific root length had significantly greater contribution to shoot P uptake, and specific root length showed the largest contribution to shoot P uptake, indicating that simultaneous increase of total root length and decrease of average root diameter can obviously improve the P uptake of wild soybean. In conclusion, wild soybean exhibited highly plastic responses of root morphology to P localized supply, and enhanced the acquisition of heterogeneous soil P by optimizing root spatial distribution and changing the root morphological traits as an effective strategy of root management.