Root plasticity, whole plant biomass, and nutrient accumulation of Neyraudia reynaudiana in response to heterogeneous phosphorus supply

Purpose The aims of this study were to examine the adaptive mechanisms of Neyraudia reynaudiana, a pioneer species rapidly colonizing degraded sites, to heterogeneous phosphorus (P) distribution, and how foraging P distributed in patches affects whole-plant biomass and nutrient accumulation.Materials and methods Plants were grown in equally divided sand-culture boxes using different concentrations of P applied either heterogeneously (0/5, 0/15, 5/15, 0/30, and 15/30 mg KH2PO4 solution/kg dry soil) or homogeneously (2.5/2.5, 7.5/ 7.5, 10/10, 15/15, and 22.5/22.5 mg kg-1) to each of the split boxes.Results and discussion After 4 months of treatment applications, a significant (p < 0.05) variation in specific root length plasticity was detected between patches of heterogeneous P availability. The largest patch strength difference (0/30 mg/kg) induced the greatest change in specific root length relative to the smallest patch strength difference (0/5 mg/kg). Root P content was not changed by the heterogeneous treatments. Although the whole plant biomass was unaffected by the P distribution pattern, the accumulation of P in the whole plant was slightly higher in the homogeneous treatment than in the heterogeneous treatment.Conclusions Plasticity of root morphological appears to be the main adaptation mechanism by which this species forages patchily distributed P. The benefit of this strategy is not reflected in increased whole-plant productivity or nutrient accumulation when P is heterogeneously distributed. The results are fundamental to understanding the mechanisms of foraging nutrient-patches and adapting to poor soil conditions.