Affiliation:
1. State Key Laboratory of Earth Surface Processes and Resource Ecology, MOE Engineering Research Center of Desertification and Blown‐Sand Control, Faculty of Geographical Science Beijing Normal University Beijing 100875 China
2. School of Biological Sciences and Institute of Agriculture University of Western Australia Crawley Perth WA 6009 Australia
Abstract
Summary
Phosphorus (P) fertilization can alleviate a soil P deficiency in grassland ecosystems. Understanding plant functional traits that enhance P uptake can improve grassland management.
We measured impacts of P addition on soil chemical and microbial properties, net photosynthetic rate (Pn) and nonstructural carbohydrate concentrations ([NSC]), and root P‐uptake rate (PUR), morphology, anatomy, and exudation of two dominant grass species: Leymus chinensis (C3) and Cleistogenes squarrosa (C4).
For L. chinensis, PUR and Pn showed a nonlinear correlation. Growing more adventitious roots compensated for the decrease in P transport per unit root length, so that it maintained a high PUR. For C. squarrosa, PUR and Pn presented a linear correlation. Increased Pn was associated with modifications in root morphology, which further enhanced its PUR and a greater surplus of photosynthate and significantly stimulated root exudation (proxied by leaf [Mn]), which had a greater impact on rhizosheath micro‐environment and microbial PLFAs.
Our results present correlations between the PUR and the Pn of L. chinensis and C. squarrosa and reveal that NSC appeared to drive the modifications of root morphology and exudation; they provide more objective basis for more efficient P‐input in grasslands to address the urgent problem of P deficiency.
Funder
National Basic Research Program of China
National Natural Science Foundation of China